Residential Glossary

Air-Conditioning: Cooling and dehumidifying the air in a building using 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 are not currently in working condition or are not used are included if they are in place in the housing unit. (See Refrigeration Unit.)

Air-Conditioning Equipment: A system, either a central system or window or wall units, that cools the air in a housing unit using a refrigeration unit driven by electricity or natural gas. Excluded are 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 still included in RECS if they are in place in the housing unit. Some central air-conditioners are heat pumps.

Apartments in Buildings with 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 and 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.

Apartments in Buildings with 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

Appliances: Appliances used in the home during the year, including those loaned to the householder for regular use. Appliances possessed by the household but not used are not counted, except for air- conditioning equipment. Appliances temporarily not in working condition but generally used by the household are included only if a repair person has been called or the appliance has been taken to a repair shop.

Authorization Form: The one-page form signed by the respondent that gives permission to the energy supplier to release information about the energy used in the housing unit. 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 certain 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.)

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. 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.

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. (See Heating Equipment and Portable Electric Heater.)

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 extra for the container.

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

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. (See Metropolitan Statistical Area (MSA), Rural, Suburban, and Urban.)

Central Warm-Air Furnace: A type of space-heating equipment in which a central combustor or resistance unit--generally using gas, fuel oil, or electricity--provides warm air that circulates 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 is used to force the 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. (See Heating Equipment.)

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 (ECD) 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 (1961-1990) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). The zones are defined as follows:

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 liquefied petroleum gas). (See Appliances.)

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 tub 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. Only statistics on the number of households using coal are collected in RECS. (See Fuel.)

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

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

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. For the RECS, the control totals were obtained from the Current Population Survey. (See Appendix A, "How the Survey Was Conducted.")

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

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 1 year. The number of 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 degree-days averaged over 30 years from 1961 to 1990 are called Normal Cooling Degree-Days. Average daily temperature is the mean of the maximum and minimum temperatures for a 24-hour period. Cooling degree-days can also be calculated using a base temperature other than 65 degrees. The computation is performed in an analogous manner. (See Heating Degree-Days [HDD] and Climate Zone.)

Cooperative: A type of ownership where a group of housing units are owned by a corporation of member-owners. Each individual member is entitled to occupy an individual housing unit and is a shareholder in the corporation that owns the property. Ownership may cover single-family houses, row houses, and townhouses, as well as apartments.

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 space protect it from the weather. A crawl space "open to the outside" is one that 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.

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. (See Appliances.)

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. (See Appliances.)

Electricity: Metered electric power supplied by a central utility company to a residence via underground or aboveground power lines. Electricity generated on site for the exclusive use of a residence is estimated using the regression equations used to impute electricity. Since 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 W or kW) or as power used over a given time (consumption expressed in kWh). The heat equivalent for electricity that comes into the home 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 3.3 times 3,412 Btu per kWh, or 11,620 Btu per kWh.

Eligible for Federal Assistance: Households are categorized as eligible for Federal energy assistance if their income is below the Federal maximum 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 maximum. (See Poverty Line.)

Energy Source: A type of energy or fuel consumed by the household. For this report, the energy sources identified are electricity, natural gas, fuel oil, kerosene, liquefied petroleum gas (propane), wood, coal, and solar energy. (See Electricity, Natural Gas, Fuel Oil, Kerosene, Liquefied Petroleum Gas [LPG], Wood, Coal, and Solar Energy.)

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

Fireplace: Usually a masonry unit that 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. Accessories, such as convective grates or radiant grates, may be present to increase the efficiency of the fireplace. 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. A free-standing fireplace that can be detached from its chimney is a heating stove. (See Heating Equipment and Heating Stove Burning Wood, Coal or Coke.)

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. (See Heating Equipment.)

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. It 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). (See Appliances.)

Frost-Free: A freezer either separate from or within a refrigerator that automatically defrosts itself every 12 or 24 hours.

Fuel: A fuel or energy source delivered to a residential site. It may be converted to some other form of energy at the site. Electricity is included as a fuel. Other fuels are coal, fuel oil, kerosene, liquefied petroleum gas (LPG), natural gas, wood, and solar.

Fuel Oil: No. 1, No. 2, or No. 4 grade fuel oil or residual oil that is burned for space- 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. (See Fuel.)

Furnace: That part of a boiler or warm-air space-heating plant in which combustion takes place. (See Heating Equipment.)

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 dehumidification of the air in a building by a refrigeration unit driven by gas (either natural gas or LPG). Such units are extremely rare. (See Refrigeration Unit.)

Group Quarters: Living arrangements for institutional groups containing 10 or more unrelated persons. They are excluded from the RECS. Group quarters are typically found in hospitals, nursing or rest homes, military barracks, ships, 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 common dining area for residents. (See Housing Unit.)

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. (See Heating Equipment.)

Heated: A room or space warmed by space-heating equipment. Basements and other areas where the space-heating equipment or heating ducts are located may be considered heated if they are warm enough to sit, work, or play in during the winter months. If a housing unit has no space-heating equipment, then there are no heated areas in the housing unit.

Heated Aquarium: A tank, used as a container for fish, that holds 20 or more gallons of heated water and is usually made of glass. A 20-gallon tank is approximately 30 inches by 12 inches by 12 inches.

Heated Floorspace (estimated): In this survey (1997), the heated floor area of the housing unit as estimated by the respondent. In past surveys, the floorspace was measured by the interviewer.

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 1 year. The number of 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; it is zero if the daily average temperature is greater than or equal to the base temperature. The number of heating degree-days for a longer period of time is the sum of the daily heating degree-days for days in that period. Annual heating degree-days averaged over 30 years from 1961 to 1990 are called Normal Heating Degree-Days. Average daily temperature is the mean of the maximum and minimum temperatures for a 24-hour period. Heating degree-days can also be calculated using a base temperature other than 65 degrees. The computation is performed in an analogous manner.

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 is temporarily out of order. A "cooking stove" may be used as the mainspace-heating equipment even though it was built for preparing food. (See descriptions of specific types of space-heating equipment: Central Warm-Air Furnace; Heat Pump [Reverse-Cycle System]; Built-In Electric Units; Steam or Hot-Water System; Floor, Wall, or Pipeless Furnace; Heating Stove Burning Wood, Coal, or Coke; and Room Heater Burning Gas, Oil, or Kerosene.)

Hot-Deck Imputation: A statistical procedure for deriving a probable response to a questionnaire item concerning a household, 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 Imputation and 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. (See Appliances.)

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 Unit, Seasonal Unit, and Migratory Unit.)

Imputation: A statistical method used to fill in values for missing items, designed to minimize the bias of estimates. (See Hot-Deck Imputation and Appendix A, "How the Survey Was Conducted.")

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 the names "range oil," "stove oil," or "coal oil." (See Fuel.)

Low-Income Home Energy Assistance Program (LIHEAP): The purpose of LIHEAP is to assist eligible households to meet the cost of heating or cooling in residential dwellings. The Federal government provides the funds to the States that administer the program.

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 household 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.

Metropolitan Statistical Area (MSA): Areas defined by the U.S. Office of Management and Budget in 1992. An MSA is (1) a county or group of contiguous counties that contain 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, MSA's consist of towns and cities, rather than counties. (See Central City, Rural, Suburban, and Urban.)

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 a browning coil and convection heating as additional features. (See Appliances.)

Migratory Unit: Housing unit intended for occupancy by migratory workers employed in farm work during the crop season. It is usually excluded from the RECS, since it is not often 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 its 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.

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

Occupied Housing Unit: A unit in which someone was living as his or her usual or permanent place of residence at the time of the interviewer's first visit to the unit. (See Housing Unit.)

Oven: An appliance that 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. (See Appliances.)

Owned/Rented: The relationship of a housing unit's occupants to the structure itself, not the land on which the structure is located. "Owned" means the owner or co-owner is a member of the household and the housing unit is either fully paid for or mortgaged. A household is classified "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.