Glossary

Here you will find an alphabetical list of technical terms related to the National Residential Efficiency Measures Database.

Absorptivity (Roof Material): The solar radiation absorptance of the outside roof surface, specified as a value between 0 and 1.
ACH (Crawlspace): Air exchange rate, in Air Changes per Hour (ACH), for the crawlspace.
Adjusted Volume (Freezer): For freezers, adjusted volume (AV) is calculated: AV = 1.73 x Total Freezer Volume. For refrigerators, AV is calculated: AV = 1.63 x Total Refrigerator Volume. For refrigerator-freezers, AV is calculated: AV= Fresh Volume + 1.63 x Total Freezer Volume.
Adjusted Volume (Refrigerator): For freezers, adjusted volume (AV) is calculated: AV = 1.73 x Total Freezer Volume. For refrigerators, AV is calculated: AV = 1.63 x Total Refrigerator Volume. For refrigerator-freezers, AV is calculated: AV= Fresh Volume + 1.63 x Total Freezer Volume.
AFUE (Direct Heater): The Annual Fuel Utilization Efficiency (AFUE) is the measure of seasonal or annual efficiency of a furnace or boiler. It takes into account the cyclic on/off operation and associated energy losses of the heating unit as it responds to changes in the load, which in turn is affected by changes in weather and occupant controls. Procedures to test AFUE are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix N to Subpart B.
AFUE (Furnace): The Annual Fuel Utilization Efficiency (AFUE) is the measure of seasonal or annual efficiency of a furnace or boiler. It takes into account the cyclic on/off operation and associated energy losses of the heating unit as it responds to changes in the load, which in turn is affected by changes in weather and occupant controls. Procedures to test AFUE are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix N to Subpart B.
AFUE (Boiler): The Annual Fuel Utilization Efficiency (AFUE) is the measure of seasonal or annual efficiency of a furnace or boiler. It takes into account the cyclic on/off operation and associated energy losses of the heating unit as it responds to changes in the load, which in turn is affected by changes in weather and occupant controls. Procedures to test AFUE are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix N to Subpart B.
Annual kWh (Dishwasher): Annual energy usage in both electricity and hot water for a year based on 215 cycles/year.
Capacity (Dishwasher): A qualitative description of the dishwasher capacity.
Capacity (Electric Baseboard): The maximum input heating rate.
Capacity (Room Air Conditioner): Cooling capacity of room air conditioner.
Cavity Depth (Wood Stud): Depth of the stud cavity.
Cavity Depth (Finished Roof): Thickness of roof framing.
Cavity Insulation Nominal R-value (Wood Stud): Insulation levels are specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it. The higher the R-value the better the thermal performance of the insulation. Nominal R-value refers to the R-value of the cavity insulation and not the overall R-value of the assembly.
Cavity Insulation Nominal R-value (Finished Roof): Insulation levels are specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it. The higher the R-value the better the thermal performance of the insulation. Nominal cavity R-value refers to the R-value of the cavity insulation and not the overall R-value of the assembly.
Cavity Insulation Type (Wood Stud): The type of insulation used in the wall cavity.
Ceiling Cavity Insulation Nominal R-value (Crawlspace): The nominal R-value of the ceiling cavity insulation.
Ceiling Cavity Insulation Nominal R-value (Unfinished Basement): Insulation levels are specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it. The higher the R-value the better the thermal performance of the insulation. Nominal R-value refers to the R-value of the cavity insulation and not the overall R-value of the assembly.
Ceiling Cavity Insulation Type (Crawlspace): The type of insulation in the ceiling cavity.
Ceiling Framing Factor (Crawlspace): Fraction of ceiling that is framing.
Ceiling Insulation Nominal R-value (Unfinished Attic): Insulation levels are specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it. The higher the R-value the better the thermal performance of the insulation. Nominal R-value refers to the R-value of the filled insulation and not the overall R-value of the assembly.
Ceiling Insulation Thickness (Unfinished Attic): The thickness in inches of insulation required to obtain a certain R-value.
Ceiling Insulation Type (Unfinished Attic): The type of insulation (e.g., cellulose or expanded polystyrene foam) used in a particular measure.
Color (Exterior Finish): A qualitative description of the exterior finish color.
Color (Roof Material): Color description used by Manual J sizing calculations.
Combined Pump and Motor Efficiency (Well Pump): The combined efficiency of the pump and motor. It represents the hydraulic power of the fluid as a percentage of the electrical power provided.
Conductivity (Exterior Finish): Conductivity of the exterior finish assembly.
Configuration (Freezer): The configuration of the freezer: compact chest, compact upright, chest, or upright. The configuration of the refrigerator: bottom mounted, side-by-side, top mounted, or unknown.
Configuration (Refrigerator): The configuration of the freezer: compact chest, compact upright, chest, or upright. The configuration of the refrigerator: bottom mounted, side-by-side, top mounted, or unknown.
Continuous Insulation Nominal R-Value (Finished Roof): R-value of rigid insulation placed on the exterior of the roof.
Continuous Insulation Nominal R-value (Wall Sheathing): Insulation levels are specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it. The higher the R-value the better the thermal performance of the insulation. Nominal R-value refers to the R-value of the continuous insulation and not the overall R-value of the assembly.
Continuous Insulation Thickness (Finished Roof): Thickness of rigid insulation added to the roof.
Continuous Insulation Thickness (Wall Sheathing): The thickness of the continuous insulation.
Continuous Insulation Type (Wall Sheathing): The type of continuous insulation in the wall assembly.
Control Type (Lighting Control): The type of control for the lighting system.
Control Type (Thermostat): The type of thermostat.
COP (Ground Source Heat Pump): User can use AHRI/ ASHRAE ISO 13556-1 rated EER value and convert it to EIR here. System will auto adjust based on AHRI rated condition and estimated user input pump head and estimated total AHU & duct static pressure drop of 1.0 inch w.g. (Default system internal static pressure drop 0.5 in.w.g with external duct system at 0 in.w.g, and condenser coil water pressure drop of 11 feet at rated condition, there may be slight variance between system to system, estimated is average value). Also note: In both DOE2 and EnergyPlus, fan and pumping power and their motor heat into air or fluid stream are both counted separately, so the fan and pump power above cannot be zeroed out.
Defrost (Freezer): The defrost type of the freezer or refrigerator, either automatic or manual.
Defrost (Refrigerator): The defrost type of the freezer or refrigerator, either automatic or manual.
Density (Exterior Finish): Density of the exterior finish assembly.
Door Type (Doors (Entry)): The amount of glazing used to classify category based on NFRC 100-2004. "Opaque" doors have 0% glazing, "<= 1/2-Lite" have less than 29.8% glazing, and "> 1/2-Lite" have more than 29.8% glazing.
Drying Energy (Clothes Dryer): The energy consumed by the clothes dryer to dry a typical load of laundry.
EER (Room Air Conditioner): This is a measure of the instantaneous energy efficiency of cooling equipment. EER is the steady-state rate of heat energy removal (e.g., cooling capacity) by the equipment in Btu/h divided by the steady-state rate of energy input to the equipment in watts. This ratio is expressed in Btu/h per watt (Btu/W-h). Procedures to test EER for central equipment are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix M to Subpart B. For room air conditioners the procedures are defined in the American National Standard (ANS) Z234.1-1972, Room Air Conditioners, Sections 4, 5, 6.1, and 6.5, and in the American Society of Heating, Refrigerating and Air Conditioning in Engineers (ASHRAE) Standard 16-69.
EER (Ground Source Heat Pump): This is a measure of the instantaneous energy efficiency of cooling equipment. EER is the steady-state rate of heat energy removal (e.g., cooling capacity) by the equipment in Btu/h divided by the steady-state rate of energy input to the equipment in watts. This ratio is expressed in Btu/h per watt (Btu/W-h). Procedures to test EER for central equipment are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix M to Subpart B. For room air conditioners the procedures are defined in the American National Standard (ANS) Z234.1-1972, Room Air Conditioners, Sections 4, 5, 6.1, and 6.5, and in the American Society of Heating, Refrigerating and Air Conditioning in Engineers (ASHRAE) Standard 16-69.
Efficiency (Electric Baseboard): The efficiency of the electric baseboard.
Efficiency High Speed (Ceiling Fan): The high speed efficiency rating of a ceiling fan as determined by the test procedure defined by the Environmental Protection Agency's ENERGY STAR Testing Facility Guidance Manual: Building a Testing Facility and Performing the Solid State Test Method for ENERGY STAR Qualified Ceiling Fans, Version 1.1, December 9, 2002.
Efficiency Level (Water Cooler): A qualitative description of the efficiency level for the water cooler.
Efficiency Low Speed (Ceiling Fan): The low speed efficiency rating of a ceiling fan as determined by the test procedure defined by the Environmental Protection Agency's ENERGY STAR Testing Facility Guidance Manual: Building a Testing Facility and Performing the Solid State Test Method for ENERGY STAR Qualified Ceiling Fans, Version 1.1, December 9, 2002.
Efficiency Medium Speed (Ceiling Fan): The medium speed efficiency rating of a ceiling fan as determined by the test procedure defined by the Environmental Protection Agency's ENERGY STAR Testing Facility Guidance Manual: Building a Testing Facility and Performing the Solid State Test Method for ENERGY STAR Qualified Ceiling Fans, Version 1.1, December 9, 2002.
Emissivity (Radiant Barrier): The property that determines the fraction of the incident radiation that is absorbed.
Emissivity (Exterior Finish): The property that determines the fraction of the incident radiation that is absorbed.
Emissivity (Roof Material): Infrared emissivity of the outside surface of the roof. Used to determine IR radiation leaving the roof surface and IR radiation from the sky, ground, and other surfaces absorbed by the roof surface.
Energy Factor (Clothes Washer): Energy Factor (EF) is the previous energy performance metric for clothes washers. It is the quotient of the capacity of the clothes container divided by the sum of the machine electrical energy and the water heating energy required for a cycle. The higher the EF the more efficient the washer. It has been replaced by the Modified Energy Factor (MEF).
Energy Factor (Freezer): The Energy Factor (EF) for freezers and refrigerators is defined as the ratio of adjusted volume to the energy consumption in one day.
Energy Factor (Water Heater): For Water Heaters, Energy Factor is the ratio of useful energy output from the water heater to the total amount of energy delivered to the water heater. The higher the EF is, the more efficient the water heater. Procedures to test the EF of water heaters are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix E to Subpart B.
Energy Factor (Clothes Dryer): The Energy Factor, for electric or gas systems.
Energy Factor (Refrigerator): The Energy Factor (EF) for freezers and refrigerators is defined as the ratio of adjusted volume to the energy consumption in one day.
Exterior Insulation Nominal R-value (Slab): The nominal R-value of the exterior insulation.
Fan (Direct Heater): This property indicates a fan for air circulation.
Film (Windows): Describes the type of window film applied to the window.
First Hour Rating (Water Heater): A measure of the capability of a water heater to meet peak demands.
Flow Rate (Sinks): The rated flow rate for the sink.
Flow Rate (Showers): The rated flow rate of the shower.
Flow Type (Sinks): A qualitative description of the flow type for the sink.
Flow Type (Showers): A qualitative description of the flow type for the showers.
Foundation Insulation Depth (Slab): The depth of the exterior foundation insulation.
Frame Material (Skylights): The material comprising the frame of a glazing system.
Frame Material (Windows): The material comprising the frame of a glazing system.
Framing Factor (Wood Stud): The fraction of a wall assembly that is comprised of structural framing.
Framing Factor (Finished Roof): The framing factor of the finished roof.
Fuel Type (Direct Heater): Type of fuel used for heating. Typically either natural gas, electricity, propane, or fuel oil.
Fuel Type (Water Heater): Type of fuel used for heating. Typically either natural gas, electricity, propane, or fuel oil.
Fuel Type (Furnace): Type of fuel used for heating. Typically either natural gas, electricity, propane, or fuel oil.
Fuel Type (Boiler): Type of fuel used for heating. Typically either natural gas, electricity, propane, or fuel oil.
Fuel Type (Clothes Dryer): Type of fuel used for heating. Typically either natural gas, electricity, propane, or fuel oil.
Gas Fill (Skylights): Type of gas filled between multiple panes of glass in a window assembly (e.g., air or argon).
Gas Fill (Windows): Type of gas filled between multiple panes of glass in a window assembly (e.g., air or argon).
Glazing Fraction (Doors (Entry)): The fraction of an entry door assembly that is glazed.
Glazing Type (Skylights): Surface treatment of a glazing system (e.g. LoE, High SHGC, etc.).
Glazing Type (Windows): Surface treatment of a glazing system (e.g. LoE, High SHGC, etc.).
Has Ice Dispenser (Refrigerator): The feature of a refrigerator to provide through-the-door ice.
Heat Exchanger Type (Ground Source Heat Pump): Vertical bore is the only available option currently.
Heater Type (Direct Heater): Description of the heater configuration and function.
HSPF (Air Source Heat Pump): The Heating Seasonal Performance Factor (HSPF) is a measure of a heat pump's energy efficiency over one heating season. It represents the total heating output of a heat pump (including supplementary electric heat) during the normal heating season (in Btu) as compared to the total electricity consumed (in watt-hours) during the same period. Procedures to test HSPF are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix M to Subpart B.
Ignition Type (Direct Heater): The manner by which the fuel is ignited.
Input-Electric (Water Heater): The maximum energy input rating of an electric water heater.
Input-Gas, Propane, or Oil (Water Heater): The maximum energy input rating of a gas, propane, or fuel oil water heater.
Install Grade (Wood Stud): Installation grade as defined by RESNET standard. 5% of the wall is considered missing insulation for Grade 3, 2% for Grade 2, and 0% for Grade 1.
Insulation Fills Cavity (Finished Roof): Specifies whether the cavity insulation completely fills the depth of the cavity. When the insulation does not completely fill the cavity, air film resistances inside the cavity are added to the insulation Rvalue.
Insulation Nominal R-Value (Distribution): The nominal R-value for hot water pipe insulation.
Insulation Nominal R-Value (Ducts): The nominal R-value for duct insulation.
IsAeratorAttachment (Sinks): A flag for whether the component is an aerator attachment.
Lamp Type (Flood Light): A general descriptor of the lamp technology.
Lamp Type (Torchiere): A general descriptor of the lamp technology.
Lamp Type (Light Bulb): The type of lamp.
Living Space ACH50 (Air Leakage): Air exchange rate, in Air Changes per Hour at 50 Pascals (ACH50), for the living space.
Loading Direction (Clothes Washer): The direction in which clothes are inserted into the wash basin.
Luminous Efficacy (Flood Light): The ratio of luminous flux to power input of a lamp. Luminous efficacy is a common metric for determining the relative energy performance characteristics of different lamp and luminaire types.
Luminous Efficacy (Light Bulb): The ratio of luminous flux to power input of a lamp. Luminous efficacy is a common metric for determining the relative energy performance characteristics of different lamp and luminaire types.
Luminous Efficacy (Torchiere): The ratio of luminous flux to power input of a lamp. Luminous efficacy is a common metric for determining the relative energy performance characteristics of different lamp and luminaire types.
Machine Energy (Clothes Dryer): Machine energy includes the energy consumed by all the mechanical and electrical processes for a clothes washer or clothes dryer.
Maintenance of Solar Reflectance (Roof Material): The solar reflectance of a roof product three years after installation under normal conditions.
Material (Doors (Entry)): The opaque material of the door assembly.
Max GPM 77 Deg F Rise (Water Heater): The amount of hot water in Gallons a tankless water heater can supply per minute over a 77 Degrees F temperature rise.
Max Supply Temp (Furnace): Maximum supply air temperature.
Modified Energy Factor (Clothes Washer): The Modified Energy Factor (MEF) is the quotient of the capacity of the clothes container, C, divided by the total clothes washer energy consumption per cycle, with such energy consumption expressed as the sum of the machine electrical energy consumption, M, the hot water energy consumption, E, and the energy required for removal of the remaining moisture in the wash load, D. The higher the value, the more efficient the clothes washer is. Procedures to test MEF are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix J to Subpart B.
Number of Place Settings (Dishwasher): The number of place settings for the unit. Data obtained from manufacturer's literature.
Occupancy Sensor (Lighting Control): The ability to control lighting based on motion detection.
Operation (Doors (Entry)): This describes the way an entry door opens.
Panes (Skylights): Number of panes of glazing in a window or skylight system.
Panes (Windows): Number of panes of glazing in a window or skylight system.
Rated Annual Energy Consumption (Freezer): The EnergyGuide rated annual energy consumption for a freezer or refrigerator.
Rated Annual Energy Consumption (Refrigerator): The EnergyGuide rated annual energy consumption for a freezer or refrigerator.
Recovery Efficiency (Water Heater): For Water Heaters, the recovery efficiency is the ratio of energy delivered to the water to the energy content of the fuel consumed by the water heater. Test procedures to test recovery efficiency are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix E to Subpart B.
Reflectivity (Radiant Barrier): The property that determines the fraction of the incident radiation that is not absorbed.
SEER (Air Source Heat Pump): Seasonal Energy Efficiency Ratio (SEER) is a measure of equipment energy efficiency over the cooling season. It represents the total cooling of a central air conditioner or heat pump (in Btu) during the normal cooling season as compared to the total electric energy input (in watt-hours) consumed during the same period. Procedures to test SEER are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix M to Subpart B.
SEER (Central Air Conditioner): Seasonal Energy Efficiency Ratio (SEER) is a measure of equipment energy efficiency over the cooling season. It represents the total cooling of a central air conditioner or heat pump (in Btu) during the normal cooling season as compared to the total electric energy input (in watt-hours) consumed during the same period. Procedures to test SEER are defined by the Department of Energy (DOE) in 10 Code of Federal Regulations Part 430, Appendix M to Subpart B.
Sensible Recovery Efficiency (Mechanical Ventilation): The net sensible energy recovered by the supply airstream as adjusted by electric consumption, case heat loss or heat gain, air leakage, airflow mass imbalance between the two airstreams and the energy used for defrost (when running the Very Low Temperature Test), as a percent of the potential sensible energy that could be recovered plus the exhaust fan energy. Values for some products can be found at the Home Ventilating Institute (hvi.org).
SHGC (Doors (Entry)): The ratio of solar heat gain through a glazing system compared to that of an unobstructed opening.
SHGC (Skylights): The ratio of solar heat gain through a glazing system compared to that of an unobstructed opening.
SHGC (Windows): The ratio of solar heat gain through a glazing system compared to that of an unobstructed opening.
Siding Type (Exterior Finish): The type of siding or cladding use in a wall assembly (e.g., wood or aluminum).
Solar Absorptivity (Exterior Finish): The property that determines the fraction of the incident radiation that is absorbed.
Solar Reflectance (Roof Material): The fraction of solar flux reflected by a surface expressed as a percent or within the range of 0.00 and 1.00 for initial installation.
Specific Heat (Exterior Finish): Specific heat of the exterior finish assembly.
Standby Energy Consumption (Water Cooler): The daily power draw of a water cooler in its lowest power mode.
Storm Sash (Windows): The type of storm sash on the window.
Stud Size (Wood Stud): The dimensions of the wall studs.
Stud Spacing (Wood Stud): The on-center spacing between studs in a wall assembly.
System Type (Boiler): The system type of the boiler.
Tank Wrap R-Value (Water Heater): The nominal R-value for tank water heater insulation wrap.
Thickness (Radiant Barrier)
Thickness (Exterior Finish): Thickness of the exterior finish assembly.
Total Leakage (Ducts): The total amount of air flow leakage expressed as a fraction of the total air flow rate.
Total Recovery Efficiency (Mechanical Ventilation): The net total energy (sensible plus latent, also called enthalpy) recovered by the supply airstream adjusted by electric consumption, case heat loss or heat gain, air leakage and airflow mass imbalance between the two airstreams, as a percent of the potential total energy that could be recovered plus the exhaust fan energy. Values for some products can be found at the Home Ventilating Institute (hvi.org).
U-Value (Doors (Entry)): The heat transfer coefficient of a material or assembly, the U-value is the inverse of R-value. It is calculated for a total window, skylight, or entry door assembly.
U-Value (Skylights): The heat transfer coefficient of a material or assembly, the U-value is the inverse of R-value. It is calculated for a total window, skylight, or entry door assembly.
U-Value (Windows): The heat transfer coefficient of the windows.
Volume (Freezer): The total storage volume of a refrigerator or freezer.
Volume (Refrigerator): The total storage volume of a refrigerator or freezer.
Wall Cavity Insulation Nominal R-value (Unfinished Basement): Insulation levels are specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it. The higher the R-value the better the thermal performance of the insulation. Nominal R-value refers to the R-value of the cavity insulation and not the overall R-value of the assembly.
Wall Cavity Insulation Type (Unfinished Basement): The type of insulation in the wall cavity.
Wall Construction Type (Unfinished Basement): The type of assembly used to attach continuous insulation or contain cavity insulation to a basement wall.
Wall Continuous Insulation Nominal R-value (Crawlspace): The nominal R-value of the continuous wall insulation.
Wall Continuous Insulation Nominal R-value (Unfinished Basement): Insulation levels are specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it. The higher the R-value the better the thermal performance of the insulation. Nominal R-value refers to the R-value of the continuous insulation and not the overall R-value of the assembly.
Wall Continuous Insulation Thickness (Unfinished Basement): The thickness of the continuous insulation.
Wall Continuous Insulation Type (Unfinished Basement): The type of continuous wall insulation.
Wall Continuous Insulation Type (Crawlspace): Type of insulation on the crawlspace wall.
Wall Finish Material (Unfinished Basement): The finish material of the wall.
Wall Framing Factor (Unfinished Basement): The percentage of a basement wall assembly that is comprised of structural framing.
Wall Insulation Height (Unfinished Basement): The insulation height on the basement wall.
Water Factor (Clothes Washer): The Water Factor (WF) is the quotient of the total weighted per-cycle water consumption, Q, divided by the capacity of the clothes washer, C. The lower the value, the more water efficient the clothes washer.
Water Service (Water Cooler): The types of water temperatures that are supplied by the water cooler. Hot and Cold Water provides Hot, Cold, and Room Temperature Water while Cold Only provides Cold and Room Temperature Water.
Water Usage (Dishwasher): This is the amount of water used to run the dishwasher for one cycle.
Wattage (Torchiere): The rated power input for a lamp.