1997 Glossary

Adequacy of Insulation: The respondent’s perception of the adequacy of the housing unit’s insulation.

Aggregate Ratio: The ratio of two population aggregates (totals). For example, the aggregate floorspace per household is the ratio of the total floorspace in each category to the total number of households in the category.

Air-Conditioning: One of the five major end-use categories in this report. Cooling and dehumidifying the air in a building by a refrigeration unit driven by electricity or natural gas. This definition excludes fans, blowers, or evaporative cooling systems (swamp coolers) that are not connected to a refrigeration unit. (See End Use and Refrigeration Unit.)

Air-Conditioning Equipment: Either a central system or window or wall units that cool the air in a housing unit by a refrigeration unit driven by electricity or natural gas. This definition excludes fans, blowers, or evaporative cooling systems (swamp coolers) that are not connected to a refrigeration unit. Air-conditioning units that were not in working condition or were not used are included if they are in place in the housing unit. If the household did not use its air-conditioning equipment during the summer of 1997, consumption and expenditures data were not imputed for air-conditioning. (See Room- Air Conditioner.)

Appliance Combination: Refers to the stub on the appliance end- use consumption table. Households are characterized as using or not using a particular combination of appliances.

Appliance Efficiency Standards: The National Appliance Energy Conservation Act of 1987 established minimum efficiency standards for major home appliances, including furnaces, central and room air- conditioners, refrigerators, freezers, water heaters, dishwashers, and heat pumps. Most of the standards were effective in 1990. The standards for clothes washers, dishwashers, and ranges were effective in 1988 because they required only minor changes in product design, such as eliminating pilot lights and requiring cold water rinse options. The standards for central airconditioners and furnaces were effective in 1992. The standards for refrigerators were effective in 1993; virtually no refrigerator models on the market in 1990 met the 1993 standards.

Appliances: One of the five major end-use categories in this report. This definition includes appliances and lights used in the home during the year, including those loaned to the householder for regular use. Appliances not currently being used are not counted unless they are temporarily out of working order and a repair person has been called or the appliance has been taken to a repair shop. Refrigerators are a separate end use. (See End Use.)

Authorization Form: The one-page form signed by respondents that gives their energy suppliers permission to release information about the energy used during a specified reporting period. The form contains the name of each energy supplier.

Automatic Set-Back or Clock Thermostat: A thermostat that can be set to turn the heating/ cooling system off and on at predetermined times.

Average: The simple arithmetic average for a population; that is, the sum of all the values in a population divided by the size of the population. Population means are estimated by computing the weighted sum of the sample values, then dividing by the sum of the sample weights. (See Weight.)

Average Age of Appliances: Respondents were provided five categories to determine the age of selected appliances (central and room air-conditioners, first and second refrigerators, freezers, water heaters and their main heating system). The midpoint of each category was used to estimate an average age of the appliances. The midpoints for each age category were as follows:

Backup Fuel: In a central heat pump system the fuel used in the furnace when the outdoor temperature drops below the level that is feasible to operate a heat pump. (See Heat Pump).

Basement: An enclosed space in which a person can walk upright under all or part of the building.

Bathroom: A full bathroom contains a sink with running water, a flush toilet, and a bathtub or shower. A half bathroom contains a toilet or bathtub or shower.

Bedroom: Room intended for sleeping, even if not presently used for sleeping. Number of bedrooms are those that would be listed as descriptive of the apartment or house if it were on the market for sale or rent. A one-room efficiency or studio apartment has no bedrooms.

Billing Period: The time between meter readings or fuel deliveries. It does not refer to the time when the bill was sent or when the payment was to have been received. In some cases, the billing period is the same as the billing cycle that corresponds closely (within several days) to meter-reading dates. For fuel oil and LPG, the billing period is the number of days between fuel deliveries.

Boiler: A type of space-heating equipment consisting of a vessel or tank where heat produced from the combustion of such fuels as natural gas, fuel oil, or coal is used to generate hot water or steam.

Btu (British thermal unit): A Btu is defined as the amount of energy required to increase the temperature of 1 pound of water by 1 degree Fahrenheit, at normal atmospheric pressure. Energy consumption is expressed in Btu in this report to allow for consumption comparisons among fuels that are measured in different units. (See Metric Conversion Factors.)

Btu Conversion Factors: The Btu conversion factors used in this report are as follows:

Built-In Electric Units: An individual-resistance electric- heating unit that is permanently installed in the floors, walls, ceilings, or baseboards and is part of the electrical installation of the building. Electric space-heating devices that are plugged into an electric socket or outlet are not considered built-in.

Cash and Carry: Kerosene, fuel oil, or bottled gas (tank or propane) purchased with cash, check, or credit card and taken home by the purchaser. The purchaser provides the container or pays for the container.

CDD: See Cooling Degree-Days (CDD).

Ceiling Fan: Fans permanently installed on the ceiling used to ventilate a room.

Census Region and Division: A geographic area consisting of several States defined by the U. S. Department of Commerce, Bureau of the Census. (See the map in Appendix F.) The States are grouped into four regions and nine divisions.

Region Division States
Northeast New England Connecticut, Maine, Massachusetts,
New Hampshire, Vermont, and Rhode Island

Middle Atlantic New Jersey, New York, and Pennsylvania

Midwest East North Central Illinois, Indiana, Michigan,
Ohio, and Wisconsin

West North Central Iowa, Kansas, Minnesota, Missouri,
Nebraska, North Dakota, and South Dakota

South South Atlantic Delaware, the District of Columbia,
Florida, Georgia, Maryland, North
Carolina, South Carolina, Virginia,
and West Virginia

East South Central Alabama, Kentucky, Mississippi,
and Tennessee

West South Central Arkansas, Louisiana, Oklahoma,
and Texas

West Mountain
Arizona, Colorado, Idaho, Montana,
Nevada, New Mexico, Utah, and Wyoming

Pacific Alaska, California, Hawaii, Oregon,
and Washington

Central Air-Conditioning: In the detailed tables, a category including households that use both room/ wall air-conditioners and central air-conditioning. (See Air-Conditioning Equipment.)

Central City: Usually one or more legally incorporated cities within the Metropolitan Statistical Area (MSA) that is significantly large by itself or large relative to the largest city in the MSA. Additional criteria for being classified "central city" include having at least 75 jobs for each 100 employed residents and having at least 40 percent of the resident workers employed within the city limits. Every MSA has at least one central city, which is usually the largest city. Central cities are commonly regarded as relatively large communities with a denser population and a higher concentration of economic activities than the outlying or suburban areas of the MSA. Suburban are those parts of the MSA that are not designated as central city. In this report, the central city and suburban areas are called urban; in previous RECS reports, these components were referred to as metropolitan areas. (See Metropolitan Statistical Area, Suburban, and Urban.)

Central Warm-Air Furnace: A type of space-heating equipment where a central combustor or resistance unit generally using natural gas, fuel oil, or electricity, providing warm air through ducts leading to the various rooms. Heat pumps are not included in this category. A forced-air furnace is one in which a fan forces air through the ducts. In a gravity furnace, air is circulated by gravity relying on the natural flow of warm air up and cold air down; the warm air rises through ducts and the cold air falls through ducts that return it to the furnace to be reheated, thus completing the circulation cycle.

City: A classification based on respondent’s judgment. (See Urban/ Rural Location.)

Climate Zone: One of five climatically distinct areas, defined by long-term weather conditions affecting the heating and cooling loads in buildings. The zones were developed by the Energy Consumption Division from seven distinct climate categories originally identified by the American Institute of Architects (AIA) for the U. S. Department of Energy and the U. S. Department of Housing and Urban Development. The zones were determined according to the 30-year average (1951- 1980) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). The zones are defined as follows:

Climate
Zone Average Annual Cooling
Degree-Days Average Annual Heating
Degree- Days
1 Under 2,000 Over 7,000
2 Under 2,000 5,500 to 7,000
3 Under 2,000 4,000 to 5,499
4 Under 2,000 Under 4,000
5 2,000 or More Under 4,000

An individual household was assigned to a climate zone according to the 30-year average annual degree-days for an appropriate nearby weather station. (See Cooling Degree-Days [CDD] ) and Heating Degree-Days [HDD].)

Clothes Dryer: An appliance that dries laundry through the application of heat and rapid air movement. The hot air used is typically heated by electricity or gas (either natural gas or LPG).

Clothes Washer: An appliance for automatically cleaning home laundry. It has an opening on its top or its front offering access to the washer tub. An agitator, located within the tub, moves the articles to be cleaned through the wash water. The machine is powered by an electric motor connected to the tub and agitator via a transmission, clutches, and linkages. In front- loading machines, the articles are moved by a rotating tube rather than an agitator.

Coal: A combustible mineral substance (carbonized vegetable matter). In this report, the term includes its derivative, coke, which is formed by destructive distillation or imperfect combustion. Data on the use of coal were collected but consumption and expenditure data were not collected .

Conditional End- Use Intensity (CEUI): A measure of how intensely energy is used that allows comparisons across housing units and households by adjusting either the end-use consumption or expenditures for the effects of certain characteristics, such as floorspace, degree-days, or household members for households that use an energy source for a particular end use. In the case of space-heating intensity, only the heated floorspace and heating degree-days are used. The air-conditioning intensity uses only the cooled floorspace and cooling degree-days. The water-heating intensity adjusts consumption and expenditures for the effects of the number of household members on water-heating consumption.

Conditional Energy Intensity: A measure of how intensely energy is used that allows comparisons across housing units and households by adjusting either energy consumption or expenditures for the effects of certain characteristics, such as weather, size of unit, and number of household members for households that use a particular energy source. (See Conditional End-Use Intensity and Intensity.)

Condo Fee: In condominiums, the fee paid to the homeowners’ association for maintenance, management, insurance, and, in some cases, utilities.

Condominium: An apartment or house owned in a project of similar units. The owner has his/her own deed and, most likely, his/her mortgage on the unit. The owner also holds a common or joint ownership on all common areas, such as hallways, entrances, and elevators. Ownership may cover single-family houses, including row houses and townhouses, as well as apartments.

Consumption: The amount of electricity or natural gas used by, or delivered to, a household during a 365-day period. For fuel oil, kerosene, and LPG, the quantity represents fuel purchased, not fuel consumed. If the level of fuel in the tank was the same at the beginning and end of the annual period, then the quantity consumed would be the same as the quantity purchased. Measurements or reports of the actual level of fuel in the tank were not included in the RECS data collection.

Control Total: The number of elements in the population or a subset of the population. The sample weights for the observed elements in a survey are adjusted so that they add up to the control total. The value of a control total is not obtained from the survey; it is obtained from an outside source. In this report, the control totals are obtained from the Current Population Survey. (See Appendix A, ”How the Survey was Conducted.”)

Conversion Factors: See Btu Conversion Factors and Metric Conversion Factors.

Cooking Stove: A stove built for preparing food. In this survey, it may be used as the main heating equipment. (See Heating Equipment.)

Cooling Degree-Days (CDD): A measure of how hot a location was over a period of time, relative to a base temperature. In this report, the base temperature is 65 degrees Fahrenheit, and the period of time is one year. The cooling degree-days for a single day is the difference between that day's average temperature and the base temperature if the daily average is greater than the base; it is zero if the daily average temperature is less than or equal to the base temperature. The number of cooling degree-days for a longer period of time is the sum of the daily cooling degree-days for the days in that period. Annual cooling degrees-days averaged over 30 years from 1961 to 1990 are called Normal Cooling Degree-days. Cooling degree-days can also be calculated by using a base temperature other than 65 degrees. The computation is performed in an analogous manner. (See Climate Zone.)

Cord of Wood: An amount of wood measuring 4 feet by 4 feet by 8 feet, or 128 cubic feet.

Crawl Space: Space between the ground and the floor of a house in which a person cannot walk upright. An enclosed crawl space is one not accessible from the outside of the house (except by a door or window) because the walls of the crawl space protect it from the weather. A crawl space "open to the outside" is accessible from outside the house, even though it may be covered by a trellis or lathwork or some kind of brickwork that leaves space for circulation of air.

Cubic Foot (cf): As a natural gas measure, the volume of gas contained in a cube with an edge that is 1 foot long at standard temperature and pressure (60 degrees Fahrenheit and 14.73 pounds standard per square inch). (See Btu Conversion Factors and Natural Gas.)

Current Dollars: Unless otherwise noted, all dollar values presented in this report are expressed in the current dollars at the time of data collection. The dollar amounts are not directly comparable across time periods since they have not been adjusted for the effects of inflation. In contrast, real dollars are current dollars that have been adjusted for the effects of inflation.

Dishwasher: A built-in or portable appliance used for automatically cleaning dishware, utensils, and cutlery. The national appliance efficiency standards required that, by 1988, dishwashers be equipped with an option to dry without heat.

Electric Air-Conditioning Intensity: In this report, the ratio of end- use electric air-conditioning consumption or expenditures to square footage of cooled floorspace and cooling degree-days (CDD) (base 65 degrees Fahrenheit). Only the CDD and square feet for households that have air-conditioning equipment are included in the ratio. The intensity provides a way of comparing different types of housing units and households by controlling for differences in housing unit size and weather conditions. The square footage of cooled floorspace is equal to the product of the total square footage times the ratio of the number of rooms that are cooled to the total number of rooms. If the entire housing unit is cooled, the cooled floorspace is the same as the total floorspace. The ratio is calculated on a weighted, aggregate basis.

Electric Pump for Well Water: A pump that forces the water from a well below ground level up into the water pipes that circulate through the house. When this pump is not working, there is a limited supply of running water in the house.

Electricity: Metered electric power delivered by a central utility company to a residence via power lines. Because there are no volumetric measures of electricity as with the fossil fuels, electricity is measured as the amount of power used at any instant (demand expressed in watts (W) or kilowatts (kW)) or as power used over a given time (consumption expressed in kWh). The heat equivalent for electricity is 3,412 Btu per kWh, but this is a derived form of energy and does not represent the amount of energy needed to generate the electricity and transmit it to the building. Generation and transmission requires about 3 times 3,412 Btu per kWh, or 11,620 Btu per kWh. Energy is used in preparing other fuels for consumption from their condition as mined and delivering them to a site for use, but these amounts of energy are relatively small compared to the Btu value of the fuel consumed. (See Primary Electricity and Btu Conversion Factors.)

Electricity Paid by Household: The household paid the electric utility company directly for all household uses of electricity (such as water heating, space heating, air-conditioning, cooking, lighting, and operating appliances.) Bills paid by a third party are not counted as paid by the household.

Eligible for Federal Assistance: Households are categorized as eligible for Federal energy assistance if their income is below the Federal standard. The Federal standard is 150 percent of the poverty line or 60 percent of statewide median income, whichever is the higher income. Individual States can set the standard at a lower level than the Federal one. (See Poverty Line.)

End Use: A function for which fuels (energy sources) are used in the household. Five major energy end-use categories were estimated: space heating, air-conditioning, water heating, refrigerators, and appliances. The amount of energy used for these end uses is estimated by means of a nonlinear regression technique, rather than by data that are actually measured. (See Space Heating, Air-Conditioning, Water Heating, Refrigerators, and Appliances.)

Energy Source: A type of energy or fuel used by the household. Electricity is included as a fuel. The energy sources identified for this report are electricity, natural gas, fuel oil, kerosene, liquefied petroleum gas (propane), wood, coal, and solar. The major fuels are electricity, natural gas, fuel oil, kerosene, and liquefied petroleum gas (LPG). (See Electricity, Natural Gas, Fuel Oil, Kerosene, Liquefied Petroleum Gas , Wood, Coal, and Solar Energy.)

Energy Supplier: A company that provides electricity, natural gas, fuel oil, kerosene, or LPG to the household. (See Authorization Form and Appendix A, "How the Survey Was Conducted.")

Estimated Bill: A set of charges for a fuel, calculated by the supplier when the meter is not read. The estimate may be based on one or more of the following factors: past usage, usage by similar households, and weather data.

Evaporative Cooler (Swamp Cooler): A type of cooling equipment using the evaporation of water to cool air. This type of equipment is commonly found in warm, dry climates. Evaporative cooling units do not cool air by use of a refrigeration unit, so for this report they are not considered air- conditioning equipment, and are listed with appliances.

Expenditures: Money spent for the energy used in, or delivered to, a housing unit during a given period of time. For this report, all expenditure statistics are presented on an annual basis for calendar year 1997. The total dollar amount includes State and local taxes but excludes merchandise, repairs, or special service charges. Electricity and natural gas expenditures are for the amount of those energy sources consumed. Fuel oil, kerosene, and LPG expenditures are for the amount of fuel purchased, which may differ from the amount of fuel consumed. For households that do not pay their fuel supplier directly, the expenditures for fuels are estimated and included in the tables. (See Consumption.)

Expenditures as a Percentage of Income: The annual household energy expenditures divided by the household’s annual income. The median percentage of income is the percentage spent on energy for the household, for the middle income value in the population when the households are ranked by the percentage they spend on energy. That is, 50 percent of the weighted households in the cell spend a lower percentage on energy than the median value.

Facsimile Machine (FAX): Equipment that transmits and receives printed material over telephone lines.

Fireplace: Usually a masonry unit which burns wood, is built into the wall of a house and has a permanent chimney. Fireplaces in mobile homes are included. Fireplaces may have glass doors or metal shields to cover the opening into the room. Included are fireplaces that use equipment fueled by natural gas or LPG. These gas fireplaces may or may not have a flue to the outside. Accessories, such as convective grates or radiant grates, may be present to increase the efficiency of the fireplace. A free-standing fireplace that can be detached from its chimney is a heating stove.

Floor, Wall, or Pipeless Furnace: Space-heating equipment consisting of a ductless combustor or resistance unit, having an enclosed chamber where fuel is burned or where electrical-resistance heat is generated to warm the rooms of a building. A floor furnace is located below the floor and delivers heated air to the room immediately above or (if under a partition) to the room on each side. A wall furnace is installed in a partition or in an outside wall and delivers heated air to the rooms on one or both sides of the wall. A pipeless furnace is installed in a basement and delivers heated air through a large register in the floor of the room or hallway immediately above.

Floorspace: The floor area of the housing unit that is enclosed from the weather. For this report, the following are included: basements, whether or not they contain finished space; finished and/or heated space in attics; and garages, if they have a wall in common with the house. Not included are: crawl spaces, even if they are enclosed from the weather; and sheds and other buildings that are not attached to the house. For this survey, floorspace was estimated using a regression equation developed with the 1993 RECS data. The 1997 RECS estimated square footage tends to be larger than the 1993 measured square footage.

Heated Floorspace: the area that is heated during most of the winter season as estimated by the respondent. Rooms that are shut off during the heating season to save fuel are not counted as heated square footage. Attached garages that are unheated and unheated areas in basements and attics are not counted as heated square feet.

Cooled Floorspace: the total floorspace times the percentage of rooms that are cooled over total rooms. This method for calculating cooled floorspace is different from the method used in Housing Characteristics 1993 that used heated floorspace rather than total floorspace.

Freezer: A cabinet designed as a unit for storing food at temperatures of about 0 degrees Fahrenheit and having a refrigeration unit driven by an electric motor. This is a separate appliance, not part of the refrigerator and can be an upright model (vertical cabinet with the door opening outward) or a chest model (horizontal cabinet with the door opening upward).

Frost-Free: A freezer, either separate from or within a refrigerator, that automatically defrosts usually on 12- or 24- hour cycles.

Fuel: A type of energy or fuel used by the household. Electricity is included as a fuel. The fuels identified for this report are electricity, natural gas, fuel oil, kerosene, LPG (propane), wood, coal, and solar. The major fuels are electricity, natural gas, fuel oil, kerosene, and LPG. (See Electricity, Natural Gas, Fuel Oil, Kerosene, Liquefied Petroleum Gas, Wood, Coal, and Solar Energy.)

Fuel Oil: A liquid petroleum product less volatile than gasoline that is burned for space- heating or water- heating purposes. No. 1 distillate fuel oil is used mostly as a blending stock to assure that heavier grades of fuel flow under severe cold weather conditions. No. 2 fuel oil is the most common form of heating oil. No. 2 distillate collectively refers to No. 2 heating oil and No. 2 diesel fuel. Although these products are not precisely identical, they are essentially interchangeable in most applications. No. 4 distillate is a blend of No. 2 and No. 5 or No. 6 residual fuel oil, used in large, stationary diesel engines and boilers equipped with fuel preheating equipment.

Fuel Oil Paid by Household: The household paid the supplier directly for all household uses of fuel oil or kerosene (such as space heating or water heating). Bills paid by a third party are not counted as paid by the household.

Furnace: Space-heating equipment consisting of an enclosed chamber where fuel is burned or electrical resistance is used to heat air directly, without using steam or hot water. The warm air is for heating, and is distributed throughout the house, typically by air ducts.

Furnace Fan: A fan that forces air through the ducts of a central warm-air furnace.

Garage: A space large enough to accommodate a car, with a door opening at least 6 feet wide and 7 feet high.

Gas Air-Conditioning: Cooling and dehumidifying the air in a building by a refrigeration unit using natural gas (either natural gas or LPG) to isolate the refrigerant. (See Refrigeration Unit.)

Gas Paid by Household: The household paid the utility company directly for all household uses of natural gas (such as water heating, space heating, air-conditioning, cooking, and operating appliances, including outdoor gas lights). Bills paid by a third party are not counted as being paid by the householder.

Group Quarters: Living arrangement for institutional groups containing 10 or more unrelated persons. Such quarters are excluded from the RECS. Group quarters are typically found in hospitals, nursing homes, military barracks, halfway houses, college dormitories, fraternity and sorority houses, convents, monasteries, shelters, jails, and correctional institutions. Group quarters may also be found in houses or apartments shared by 10 or more unrelated persons. Group quarters are often equipped with a dining area for residents. (See Housing Unit.)

HDD: See Heating Degree-Days (HDD).

Heat Pump (Reverse Cycle System): A year-round heating and air-conditioning system in which refrigeration equipment supplies both heating and cooling through ducts leading to individual rooms. A heat pump generally consists of a compressor, both indoor and outdoor coils, and a thermostat. In the RECS, all heat pumps are considered to be electric.

Heated Aquarium: A tank, usually made of glass, containing fish and holding 20 or more gallons of heated water. A 20- gallon tank measures approximately 30 inches by 2 inches by 12 inches.

Heated Floorspace (estimated): In this survey, the heated floorspace of the housing unit as estimated by the respondent. (See Floorspace.)

Heating Degree-Days (HDD): A measure of how cold a location was over a period of time, relative to a base temperature. In this report, the base temperature used is 65 degrees Fahrenheit and the period of time is one year. The heating degree-days for a single day is the difference between the base temperature and the day's average temperature if the daily average is less than the base, and zero if the daily average temperature is greater than or equal to the base temperature. The heating degree-days for a longer period of time is the sum of the daily heating degree-days for days in that period. Average daily temperature is the mean of the maximum and minimum temperature for a 24-hour period. Heating degree- days can also be calculated by using a base temperature other than 65 degrees. The computation is performed in an analogous manner. (See Climate Zone.)

Heating Equipment: The equipment used for heating ambient air in the housing unit, such as central warm-air furnace; heat pump; built-in electric units; steam or hot- water system; floor, wall or pipeless furnace; heating stove; room heater; fireplace; or portable heater. The main space-heating equipment is reported as such even if it was built for preparing food. (See: Central Warm-Air Furnace; Heat Pump; Built-In Electric Units; Steam or Hot-Water System; Floor, Wall or Pipeless Furnace; Heating Stove Burning Wood, Coal, and Coke; and Room Heater Burning Gas, Oil, and Kerosene.)

Heating Stove Burning Wood, Coal, and Coke: Any free-standing box or controlled-draft stove; or a stove installed in a fireplace opening, using the chimney of the fireplace. Stoves are made of cast iron, sheet metal, or plate steel. Free-standing fireplaces that can be detached from their chimneys are considered heating stoves.

Hispanic Descent: The question, "Is the householder of Spanish or Hispanic origin or descent," as well as the question on “origin” was determined by the respondent without any assistance from the interviewer. The interviewer was trained to record the respondent's answer.

Hot-Deck Imputation: A statistical procedure for deriving a probable response to a questionnaire item for which a response is missing. To perform the procedure, an analyst sorts the households by variables related to the missing item. Thus, a series of sort categories are formed, which are internally homogeneous with respect to the sort variables. Within each category, households for which the questionnaire item is not missing are randomly selected to serve as "donors" to supply values for the missing item of "recipient" households. (See Appendix A, ”How the Survey Was Conducted.”)

Hot Tub: A water-filled wood, plastic, or ceramic container in which up to 12 people can lounge. Normally equipped with a heater that heats the water from 80 to 106 degrees Fahrenheit. It may also have jets to bubble the water. The water is not drained after each use. An average- size hot tub holds 200 to 400 gallons of water. All reported hot tubs were assumed to include an electric pump. Hot Tubs are also called Spas or Jacuzzis.

Household: A family, an individual, or a group of up to nine unrelated persons, occupying the same housing unit. "Occupy" means that the housing unit was the person's usual or permanent place of residence at the time of the first field contact. Household members include babies, lodgers, boarders, employed persons who live in the housing unit, and persons who usually live in the household but are away traveling or in a hospital. Not included as household members are: (1) persons who are normally members of the household but who were away from home as college students or members of the armed forces at the time of the interview; (2) persons temporarily visiting with the household if they have a place of residence elsewhere; (3) persons who take their meals with the household but usually lodge or sleep elsewhere; (4) domestic employees or other persons employed by the household who do not sleep in the same housing unit; (5) or former members of the household who have become inmates of correctional, penal, or mental institutions, homes for the aged or needy, nursing homes, hospitals, hospices, convents or monasteries, or other places in which residents may remain for long periods of time. By definition, in this report, the number of households is the same as the number of occupied housing units. (See Primary Residence.)

Household Income Category: The income grouping for the total combined income from all sources (before taxes and deductions) of all household members during the 12 months prior to the interview, regardless of whether they were living there at the time of the interview. Sources of income include the following: wages, salaries, tips, commissions, interest, dividends, rental income, Social Security or railroad retirement, pensions, food stamps, Aid to Families with Dependent Children, unemployment compensation, Supplemental Security Income, General Assistance and other public assistance.

Household Member: See Household.

Householder: The person (or one of the people) in whose name the home is owned or rented. If there is no lease or similar agreement, or if the person who owns the home or pays the rent does not live in the housing unit, the householder is the person responsible for paying the household bills, or whoever is generally in charge.

Housing Unit: A house, an apartment, a group of rooms, or a single room if it is either occupied or intended for occupancy as separate living quarters by a family, an individual, or a group of one to nine unrelated persons. Separate living quarters means the occupants (1) live and eat separately from other persons in the house or apartment and (2) have direct access from the outside of the building or through a common hall--that is, they can get to it without going through someone else's living quarters. Housing units do not include group quarters where 10 or more unrelated persons live. Hotel and motel rooms are considered housing units if occupied as the usual or permanent place of residence. (See Primary Residence, Group Quarters, Year-Round Units, Seasonal Units, and Migratory Units.)

Housing Unit Record Sheet: A form (pink sheet) completed by interviewers for each housing unit assigned for contact. The type of housing unit is recorded, as well as information about each visit.

Intensity: This is a method used to make comparisons of how intensely energy is used across housing units, time, regions of the country, and/ or fuels by adjusting either the energy consumption or expenditures, for the effects of various housing unit and/or household characteristics, such as size of the housing unit, climate, and number of household members. (See Conditional End-Use Intensity, and Conditional Energy Intensity.)

Jacuzzi: See Hot Tub.

Kerosene: A distilled product of oil or coal with the generic name kerosene, having properties similar to those of No. 1 fuel oil. It is sometimes sold under names of "range oil," "stove oil," or "coal oil."

Kerosene Paid by Household: The household paid the fuel supplier directly for all household uses of kerosene (such as water heating and space heating). Bills paid by a third party are not counted as paid by the household.

Kilowatthour (kWh): A unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu. (See Btu and Btu Conversion Factors.)

Laser Printer for Computer (not dot matrix): A computer printer that uses toner, a black powder, for the printer’s ink and provides high quality printing.

Lighting: An electricity energy end use, sometimes reported separately, but more commonly combined with appliances end use in this report. Lighting is defined as the energy used to supply electricity to light bulbs inside and outside of the housing unit. All types of light bulbs are included: incandescent, fluorescent, compact fluorescent, halogen, and high-intensity-discharge (HID). (See Appliances and End Use.)

LIHEAP: See Low-Income Home Energy Assistance Program.

Liquefied Petroleum Gas (LPG): Any fuel gas, such as propane or butane, supplied to a residence in liquid form. It is usually delivered by tank trucks and stored near the residence in a tank or cylinder until used. Propane was the most common liquefied petroleum gas supplied to RECS households.

Low-Income Home Energy Assistance Program (LIHEAP): This program provides assistance to eligible low-income households in paying the costs for heating or cooling their housing unit. The States administer the program using funds provided by the Federal government.

LPG Paid by Household: The household paid the fuel supplier directly for all household uses of LPG (such as water heating, space heating, air-conditioning, operating appliances, and cooking (other than cooking on an outdoor grill, which is excluded). Bills paid by a third party are not counted as paid by the household.

Main: Used Most, as in "Main Heating Equipment," e. g., is the equipment used most for space heating.

Master-Metering: Measurement of electricity or natural gas consumption of several tenants or housing units using a single meter. That is, one meter measures the energy usage for several households collectively. RECS identifies households that pay their own fuel bills but does not specifically identify a building as "master metered."

Mean Indoor Temperature: The "usual" temperature inside the housing unit. If different sections of the house are kept at different temperatures, the reported temperature is for the section where the people are. A thermostat setting is accepted if the temperature is not known.

Metric Conversion Factors: Estimates are presented in customary U. S. units. Floorspace estimates may be converted to metric units by using this relationship: 1 square foot is approximately equal to .0929 square meters. Energy estimates may be converted to metric units by using this relationship: 1 Btu is approximately equal to 1,055 joules; 1 kWh equals 3,600,000 joules; and 278 kWh are approximately equal to 1 gigajoule.

Metropolitan: See Urban.

Metropolitan Statistical Area (MSA): As defined by the U. S. Office of Management and Budget in 1993: “a county or group of contiguous counties that contain (1) at least one city of 50,000 inhabitants or more, or (2) an urbanized area of at least 50,000 inhabitants and a total MSA population of at least 100,000 (75,000 in New England).” The contiguous counties are included in an MSA if, according to certain criteria, they are essentially metropolitan in character and are socially and economically integrated with the central city. In New England, MSAs consist of towns and cities, rather than counties.

Metropolitan Statistical Area Status: In the detailed tables, a category including housing units located in urban (central city and suburban) and rural areas as defined by the U. S. Office of Management and Budget in 1993. (See Metropolitan Statistical Area, Urban, and Rural.)

Microwave Oven: A household cooking appliance consisting of a compartment designed to cook or heat food by means of microwave energy. It may also have as additional features, browning coil and convection heating/cooking.

Migratory Units: Housing units intended for occupancy by migratory workers employed in farm work during the crop season. It is excluded from the RECS if it is not the primary residence for more than 6 months of the year. (See Primary Residence.)

Mobile Home: A housing unit built on a movable chassis and moved to the site. It may be placed on a permanent or temporary foundation and may contain one room or more. If rooms are added to the structure, it is considered a single- family housing unit. A manufactured house assembled on site is a single- family housing unit, not a mobile home.

Modem: A device connecting a personal computer to a telephone line that permits communication with computers or other devices outside the housing unit.

More Than One May Apply: This phrase indicates overlapping categories in a row stub. A particular household may be represented in more than one line. In general, row stubs without this phrase are exclusive.

Multifamily (2 to 4 units): A unit in a building with two to four housing units--a structure that is divided into living quarters for two, three, or four families or households in which one household lives above another. This category also includes houses originally intended for occupancy by one family (or for some other use) that have since been converted to separate dwellings for two to four families. Typical arrangements in these types of living quarters are separate apartments downstairs and upstairs or one apartment on each of three or four floors.

Multifamily (5 or more units): A unit in a building with five or more housing units--a structure that contains living quarters for five or more households or families and in which one household lives above another.

Multistage Area Probability Sample: A sample design executed in stages with geographic "clusters" of sampling units selected at each stage. This procedure reduces survey expense while maintaining representative national coverage.

Natural Gas: Hydrocarbon gas (mostly methane) delivered as an energy source to individual buildings by pipelines from a central utility company. Natural gas does not refer to LPG. A few households were supplied by a privatelyowned gas well.

Nonmetropolitan: See Rural.

Normal Degree-Days: Annual cooling or heating degree- days averaged over 30 years (from 1961 to 1990).

Occupied Housing Unit: A unit with someone living in it as his/her usual or permanent place of residence at the time of the interviewer’s first visit.

Origin: The householder’s primary racial background as determined by the respondent. For this question, as well as the Hispanic descent question, the interviewer just recorded the respondent’s answer. The word “race” was not used in either the questionnaire or the instructions, "Which of the groups on this exhibit best describes the householder?" The groups of origin included: white, black or Afro- American, Native American, Alaskan native, Asian, and Pacific Islander.

Oven: An appliance which is an enclosed compartment supplied with heat and used for cooking food. Toaster ovens are not considered ovens. The range stove top or burners and the oven are considered two separate appliances, although they are often purchased as one appliance.

Owned/Rented: The relationship of a housing unit's occupants to the structure itself, not the land on which the structure is located. A household is classified as "owned" when the owner or co-owner is a household member and the housing unit is either fully paid for or mortgaged. A household is classified as "rented" even if the rent is paid by someone not living in the unit. “Rent free” means the unit is not owned or being bought and no money is paid or contracted for rent. Such units are usually provided in exchange for services rendered or as an allowance or favor from a relative or friend not living in the unit. Unless shown separately, rent-free households are grouped with rented households.

Ownership: See Owned/Rented.

Pay for Electricity for Air-Conditioning: Household uses electricity for air-conditioning and pays directly to a utility company for that use.

Payment Method for Utilities: Method by which fuel suppliers or utility companies were paid for all electricity, natural gas, fuel oil, kerosene, or LPG used by a household. Households that paid the utility company directly were classified in this survey as "all paid by household." Households that paid directly for at least one but not all of their fuels and that had at least one fuel charge included in the rent were classified as "some paid, some included in rent." Households for which all fuels used were included in the rent were classified as "all included in rent." Some households were classified as "other method," if they did not fall into any of those three categories. These are households for which fuel bills were paid by a social service agency or a relative, and households that paid for some of their fuels used but paid for other fuels through another arrangement.

Personal Computer: Included as an appliance in RECS, a microcomputer for producing written, programmed, or coded material, playing games, or doing calculations. Lap-top and notebook computers are excluded.

Portable Electric Heater: A heater that uses electricity and that can be picked up and moved.

Portable Kerosene Heater: A heater that uses kerosene and that can be picked up and moved.

Poverty Line: Low-income classifications to which certain households are assigned. "Below 100 percent of poverty" encompasses a group of households with incomes below the poverty level as defined by the U. S. Bureau of the Census and the Office of Management and Budget. "Below 125 percent of poverty" includes a group of households with incomes below 125 percent of the poverty level. These groups of the poor and near-poor represent alternative levels for defining poverty. The poverty line varies with the number of family members in the household and the income of the entire family.

Primary Electricity: A measurement of electricity that includes the approximate amount of energy used to generate electricity. To approximate the adjusted amount of electricity, the site-value of the electricity is multiplied by a factor of three. This conversion factor of three is a rough approximation of the Btu value of raw fuels used to generate electricity in a steam- generation power plant. In this report, electricity is represented as site energy. (See Site Energy and Btu Conversion Factors.)

Primary Residence: A housing unit in which a householder spends the largest part of the calendar year; and is the householder's usual or permanent place of residence. This would normally be a year- round housing unit. It would generally exclude migratory and seasonal units. However, if a seasonal unit happened to be occupied for half of the year by the householder, that unit would be considered the primary residence. (See Housing Unit and Seasonal Unit.)

Primary Sampling Unit (PSU): A sampling unit selected at the first stage in multistage area probability sampling. A PSU typically consists of one to several contiguous counties--for example, a metropolitan area with surrounding suburban counties. PSU's can be composed of one or more MSAs or can be composed of rural counties.

Propane: See Liquefied Petroleum Gas.

Public Housing: Housing units owned by a local housing authority or other local public agency, such as a housing and redevelopment authority or a housing development agency. These organizations receive subsidies from the Federal or State government, but the local agency owns the property. To live in such a project, one must apply to the local housing authority.

Quadrillion: The quantity 1,000,000,000,000,000 = (10 ). 15

Race: See Origin.

Radiator: A heating unit that is usually exposed to view within the room or space to be heated and that transfers heat by radiation to objects within visible range and by conduction to the surrounding air, in turn, is circulated by natural convection. The unit is usually fueled by steam or hot water.

Range: The range burners or stove top and the oven are considered two separate appliances. Counted also with range tops are stand-alone "cook tops."

Refrigeration Unit: A unit used to produce cooling in refrigerators, freezers, and air-conditioning equipment. In a typical refrigeration unit, electricity powers a motor that runs a pump to compress a refrigerant to maintain proper pressure. (A substance that changes between liquid and gaseous forms under desirable temperature and pressure conditions.) Heat from the compressed liquid is removed and discharged from the unit, and the refrigerant evaporates when pressure is reduced. As it evaporates, it picks up heat and returns to the compressor to repeat the cycle.

A few refrigeration units use gas (either natural gas or LPG) in an absorption process that does not use a compressor. The gas is burned to heat a chemical solution in which the refrigerant has been absorbed. Heating drives off the refrigerant, which is later condensed and evaporates by released pressure and, in turn, picks up heat. The evaporated refrigerant is then changed back into the chemical solution and the heat is removed from the solution and discharged as waste heat; then the process repeats itself.

Refrigerators: A cabinet designed for cooling food at temperatures above 32 degrees Fahrenheit. Most also have a second compartment for freezing and storing frozen foods at temperatures of 8 degrees Fahrenheit or below.

Regression Imputation: A statistical technique for predicting the value of a numerical variable that is missing. The technique involves developing a regression equation that predicts the value of the missing variable based upon variables that are not missing or have already been imputed. A random error is usually added to the predicted value. The sum of the predicted value and the random error are used as the imputed value for the missing variable.

Renewable Energy: Energy obtained from sources that are essentially inexhaustible (unlike, for example, the fossil fuels, of which there is a finite supply). Renewable sources of energy include wood, waste, geothermal, wind, photovoltaic cells, and solar thermal energy.

Rent: See Owned/Rented.

Residential: Occupied housing units, including mobile homes, single-family housing units (attached and detached), and apartments. The definition of "occupied housing units" is the same as that used by the U. S. Bureau of the Census. (See Household and Housing Unit.)

Residential Building: A structure used primarily as a dwelling for one or more households.

Residential Energy Consumption Survey (RECS): A national multistage probability sample survey conducted by the Energy Consumption Division of the Energy Information Administration. The RECS provides baseline information on how U. S. households use energy.

Room-Air Conditioner: Electric-powered air-conditioning units that typically fit into the window or wall and are designed to cool only one room. (See Air-Conditioning Equipment.)

Room Heater Burning Gas, Oil, and Kerosene: Any of the following space- heating equipment: circulating heaters, convectors, radiant gas heaters, space heaters, or other nonportable room heaters that may or may not be connected to a flue, vent, or chimney.

Rooms: Subdivisions of a housing unit. Whole rooms are rooms such as living rooms, dining rooms, bedrooms, kitchens, lodgers' rooms, finished basements or attic rooms, recreation rooms, and permanently enclosed sun porches that are used year round. Rooms used for offices by a person living in the unit are included. "Finished" means that the ceiling and walls are covered with finishing materials.

Not considered to be rooms in this survey are bathrooms, halls, foyers or vestibules, balconies, closets, alcoves, pantries, strip or pullman kitchens, laundry or furnace rooms, unfinished attics or basements, open porches, and unfinished space used for storage.

A partially divided room, such as a dinette next to a kitchen or a living room, is considered a separate room only if there is a partition from floor to ceiling--but not if the partition consists solely of shelves or cabinets. If a room is used by occupants of more than one unit, the room is included with the unit from which it is most easily reached. (See Bathroom and Bedroom.)

RSE Column Factor: An adjustment factor that appears above each column of the detailed tables and is used to compute RSE's. The column factor is equal to the geometric mean of the RSE’s in a particular column of the main tables. (See RSE or Relative Standard Error, and RSE Row Factor.)

RSE or Relative Standard Error: A measure of the reliability or precision of a survey statistic on a percentage scale. Variability occurs in survey statistics because different samples that could be drawn would each produce different values for the survey statistics. The RSE is defined as the standard error (the square root of the variance) of a survey estimate, divided by the survey estimate and multiplied by 100 (expressed as a percent of the estimate). For example, an RSE of 10 percent means that the standard error is one-tenth as large as the survey estimate. The RSE is also known as the coefficient of variation. For a survey estimate in a particular row and column of a table (that is, a particular "cell"), the approximate RSE is obtained by multiplying the RSE row factor by the RSE column factor for that cell.

RSE Row Factor: An adjustment factor that appears to the right of each row of the detailed tables and is used to compute RSE's. The row factor is equal to the geometric mean of the RSE’s in a particular row of the main tables. (See RSE Column Factor and RSE or Relative Standard Error.)

Rural: Households not located within MSA’s as defined by the U. S. Office of Management and Budget in 1993. In the detailed tables, rural is included in the Metropolitan Statistical Area Status category, which is based on the definition provided by the U. S. Office of Management and Budget for 1997 and rural is included in the Urban/Rural Location category, which is based on the respondent's judgment. (See Metropolitan Statistical Area, Urban/ Rural Location and Metropolitan Statistical Area Status.)

Seasonal Energy Efficiency Ratio (SEER): Ratio of the cooling output divided by the power consumption. It is the Btu of cooling output during its normal annual usage divided by the total electric energy input in watt-hours during the same period. This is a measure of the cooling performance for rating central air-conditioners and central heat pumps. The appliance standards require a minimum SEER of 10 for split-system central air-conditioners and for split-system central heat pumps. These new standards took effect in 1992. The average heat pump or central air-conditioner sold in 1986 had a SEER of about 9.

Seasonal Units: Housing units intended for occupancy at only certain seasons of the year. Included are units intended only for recreational use, such as beach cottages and hunting cabins. Seasonal units are not usually included in the RECS occupied housing unit count unless they are occupied for more than half of the year. (See Primary Residence.)

Second Home: By definition, a second home is not the primary residence of a householder and is not included in the RECS occupied housing unit count. (See Housing Unit, Primary Residence, and Seasonal Unit.)

Secondary Heating Equipment: Space-heating equipment used less often than the main space-heating equipment. (See Main.)

Secondary Heating Fuel: Fuels used in secondary space-heating equipment.

Setback Temperature Behavior: These data were derived from differences in the temperature settings reported by respondents for their daytime temperature when someone is at home, daytime temperature when no one is at home, and the temperature for sleeping hours (assumed to be nighttime). For example, if a respondent's reported temperature setting was lower when no one was at home than when someone was at home, respondents were assumed to be "setting" back the temperature.

Single-Family: A housing unit, detached or attached, that provides living space for one household or family. Attached houses are considered single-family houses as long as the house itself is not divided into more than one housing unit and has an independent outside entrance. A single-family house is contained within walls extending from the basement (or the ground floor, if there is no basement) to the roof. A mobile home with one or more rooms added is classified as a single- family home. Townhouses, rowhouses, and duplexes are considered single-family attached housing units, as long as there is no household living above another one within the walls extending from the basement to the roof to separate the units.

Site Energy: The Btu value of energy at the point it enters the home, sometimes referred to as "delivered" energy. (See Btu Conversion Factors and Primary Electricity.)

Solar Energy: The radiant energy of the sun which can be converted into other forms of energy, such as heat or electricity.

Spa: See Hot Tub.

Space Heating: One of the five major end-use categories in this report. The use of energy to generate heat in housing units using space-heating equipment. The equipment could be the main or secondary space-heating equipment. It does not include the use of energy to operate appliances (such as lights and televisions) that give off heat as a byproduct. (See End Use and Heating Equipment.)

Space-Heating Equipment: See Heating Equipment.

Split System: When applied to electric air-conditioning equipment, it means a two-part system—an indoor unit and an outdoor unit. The indoor unit is an evaporator coil mounted in the indoor-circulating air system, and the outdoor unit is an air-cooled condensing unit containing an electric motor-driven compressor and condenser fan and fan motor.

Square Feet: See Floorspace.

Standard Price: Average price data were obtained from other EIA surveys and used in the end- use regression equations for natural gas and electricity. These average prices were attached to each 1997 RECS household that used the respective fuel.

Steam or Hot-Water System: Either of two types of a central space-heating system that supplies steam or hot water to radiators, convectors, or pipes. The more common type supplies either steam or hot water to conventional radiators, baseboard radiators, convectors, heating pipes embedded in the walls or ceilings, or heating coils or equipment that are part of a combined heating/ ventilating or heating/air-conditioning system. The other type supplies radiant heat through pipes that carry hot water and are inlaid in a concrete slab floor.

Stock: The total number of household appliances or housing units in use at a given time, including newly purchased ones and those in use for some time.

Stove: See Heating Stove Burning Wood, Coal and Coke, and Cooking Stove.

Structure: The type of building in which the housing unit was located. The four categories include single-family, multifamily (2- 4 units), multifamily (5 or more units), and mobile home. (See Single Family, Multifamily (2 to 4 units), Multifamily (5 or more units), and Mobile Home.)

Submetered Data: End-use consumption data obtained for individual appliances from recording devices attached to the appliance to measure the amount of energy it consumed.

Suburban: Those parts of the MSA that are not designated as a central city. In the detailed tables under the urban/rural location category, the central city and suburban areas are called urban; and, under the metropolitan status category, these components are referred to as metropolitan areas. (See Central City, Metropolitan Statistical Area, and Urban.)

Suburbs: Classification based on respondent’s judgment. (See Urban/Rural Location).

Swimming Pool Heater: Optional heating equipment that heats the pool water to an acceptable level of comfort, usually 80 to 85 degrees Fahrenheit.

Swimming Pool Pump: An electric pump for filtering and circulating the water.

Telecommuting: Instead of commuting to a place of employment, the household member works at home using a personal computer to connect via modem to the employment site.

Temperature: Respondents’ reported estimates of the indoor temperature. If different sections of the house are kept at different temperatures, the temperature requested is for the part of the house being used. If the heat was turned off upstairs during the day because the family was downstairs, the downstairs temperature was used. If the respondent does not know the temperature, the thermostat setting was used.

Thermostat: A device that adjusts the amount of heating and cooling produced and/ or distributed by automatically responding to the temperature in the environment.

30-Year Average Degree-Days: Annual cooling or heating degree-days averaged over 30 years (from 1961 to 1990). The 30-year average is considered "normal weather" for a region. (See Cooling Degree-Days and Heating Degree-Days.)

Toaster Oven: Portable table-top appliance used for heating or broiling food. It is not included in the “oven” category.

Town: Classification based on respondent’s judgment. (See Urban/Rural Location.)

Transported Gas: Natural gas physically delivered to a housing unit by a utility but not bought from that utility. A separate transaction is made to purchase the volume of gas and the utility is paid for the use of its pipeline to deliver the gas.

Urban: Refers to a group of housing units located within the MSA and is composed of a central city and suburban areas as defined by the U. S. Office of Management and Budget in 1997. (See Central City, Metropolitan Statistical Area, and Suburban.)

Urban/Rural Location: In the detailed tables, a category based on the respondent’s judgment. Respondents classified their households as being located in a city, town, the suburbs, or rural/ open country.

Utilities Paid by Household: Householder directly pays an energy supplier for all uses of a fuel or fuel types used.

Vacant Housing Unit: A housing unit not occupied when the first RECS field contact was made. An occupied seasonal or migratory housing unit is classified as vacant at the time of the first contact if all of its occupants had a usual place of residence elsewhere.

Vehicles: For this survey, motorized vehicles used by U. S. households for personal transportation. Excluded are motorcycles, mopeds, large trucks, and buses. Included are automobiles, station wagons, passenger vans, cargo vans, motor homes, pickup trucks, and jeeps or similar sports utility vehicles. To be included, vehicles must be: (1) owned by members of the household, or (2) company cars not owned by household members but regularly available to household members for their personal use and ordinarily kept at home, or (3) rented or leased for 1 month or more.

Water-Bed Heater: An appliance that uses an electric resistance coil to maintain the temperature of the water in a water bed at a comfortable level.

Water Heated by a Space-Heating System: Furnaces that provide hot water as well as heat to the home. The water is heated by a coil that is part of the heating system. There is not a separate hot water tank for these systems.

Water Heater: An automatically controlled, thermally insulated vessel designed for heating water and storing heated water at temperatures less than 180 degrees Fahrenheit .

Water Heater Size: Respondents were asked the size of their water heater tank. Three categories were provided: small (30 gallons or less), Medium (31 to 49 gallons), and Large (50 gallons or more). Households were not asked this question if they shared a water heater with other housing units. (See Water Heated by a Space-Heating System.)

Water Heating: One of the five major end-use categories in this report. The use of energy to heat water for hot running water, as well as the use of energy to heat water on stoves and in auxiliary water-heating equipment for bathing, cleaning, and other noncooking applications of hot water. This category does not include energy used to heat water for (1) cooking , (2) hot drinks, and (3) a swimming pool. These are included in the appliance end-use category. (See End Use.)

Water-Heating Fuel: The fuel used to heat water for washing or bathing. The hot water may have been available anywhere in the same building as the respondent's living quarters--in a hallway, in a room used by several units in the building, in the basement, or in an enclosed porch--provided the respondent's household had access to it.

Water-Heating Intensity: The amount of energy used per household member to heat water. (See Water Heating.)

Weight: The number of U. S. households that a particular sample unit represents. The estimate of the number of households with a certain characteristic (such as the use of electricity as the main space-heating fuel) equals the sum of the weights over the set of households with the characteristics.

Well Pump: See Electric Pump for Well Water.

Windows: Openings in the housing unit envelope that contains framed glass. Generally, each window that opens separately is counted as one window. Double-hung slider windows count as one window. Panes of glass in a large window are not counted separately unless they open separately. Not counted are windows in unheated spaces, such as a garage, or unheated basement and windows (glass panels) in doors.

Wood: A fuel in the form of wood logs, chips, or wood products that are burned for their heat or aesthetic value.

Wood Consumption: The amount of wood burned in a fireplace, stove, or furnace in the household at any time during the preceding 12 months. A cord of wood measures 4 feet by 4 feet by 8 feet and is approximately 128 cubic feet. To help respondents accurately report the amount of wood they burned, respondents were shown a drawing of a person, as a point of reference, standing beside 1-, 5-, and 10-cord wood piles.

Wood Conversion to Btu: An imprecise procedure for converting cords of wood into a Btu equivalent. Besides errors of memory inherent in the task of adding up the use of wood over a 12-month period, the estimates are subject to problems in the definition and the perception of a cord. The nominal cord as delivered to a suburban residential buyer may differ from the dimensions of the standard cord. This difference is possible because wood is most often cut in lengths that are longer than what makes a third of a cord (16 inches) and shorter than what makes a half cord (24 inches).

In other cases, wood is bought or cut in unusual units (for example, pickup truck-load or trunk load). Volume estimates are difficult to make when the wood is left in a pile instead of being stacked. Other factors that make it difficult to estimate the Btu value of the wood burned is that the amount of empty space between the stacked logs may vary from 12 to 40 percent of the volume. Moisture content may vary from 20 percent in dried wood to 50 percent in green wood. (Moisture reduces the useful Btu output because energy is used in driving off the moisture.) Also, some tree species contain twice the Btu content of species with the lowest Btu value. Generally, hard woods have greater Btu value than soft woods. Wood was converted to Btu at the rate of 20 million Btu per cord, which is a rough average that takes all these factors into account. (See Btu Conversion Factors.)

Year of Construction: The year the structure was originally completed or the year any part of the structure was first occupied. For mobile homes, year of construction is the model year.

Year-Round Units: Housing units occupied or intended for occupancy at any time during the year. (See Housing Unit.)

Footnote

1 Average energy input of the generation process for fossil fuel utility plants in the United States for 1993. See Energy Information Administration, Monthly Energy Review, April 1995.

Contact:

Eileen M. O'Brien

RECS Survey Manager

Phone: (202) 586-1122

Fax: (202) 586-0018

 

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