Efficiency Qualifier

Variations in the quantification of the effectiveness with which equipment, a product, process, or system performs.

Data Type: 
Constrained List
Unit of Measure: 
Commercial, Residential, Multifamily
List Options Option Definition Unit of Measure
Annual cooling Overall annual efficiency of a cooling system None
Annual heating Overall annual efficiency of a heating system None
Battery energy ratio The ratio of accumulated non-active energy divided by battery energy. None
Boiler Efficiency of boiler equipment None
Combined energy factor Combined Energy Factor (CEF) is the energy performance metric for clothes dryers; the higher the CEF the more efficient the clothes dryer. CEF is the quotient of the test load size, 8.45 lbs for standard dryers and 3 lbs for compact dryers, C, divided by the sum of the machine electric energy use during standby and operational cycles. The equation is shown here: CEF = C (lbs) / (Eon + Estandby). The units are pounds per kWh, the higher the value, the more efficient the clothes dryer is. None
Combustion The measure of how much energy is extracted from the fuel and is the ratio of heat transferred to the combustion air divided by the heat input of the fuel. (0-1) None
Efficacy The amount of light (luminous flux) produced by a light source, usually measured in lumens, as a ratio of the amount of power consumed to produce it, usually measured in watts. None
Efficiency A ratio of output to input. None
Energy conversion The percentage of the energy to which the cell is exposed to (input resource) that is actually converted into effective energy (output resource) under standard testing conditions. For solar cells, this is calculated by dividing a cell's power output (in watts) at its maximum power point by the input light (in watts per square meter) and the surface area of the solar cell (in square meters). None
Energy factor A factor is used to compare the relative efficiency of water heaters, dishwashers, clothes washers, and clothes dryers. Energy Factor (EF) is the quotient of the capacity equipment divided by the sum of the equipment electrical energy for mechanical operation or standby, and the water heating energy. The units are volume (or weight) per energy per cycle. For dishwashers, the EF is the reciprocal of the sum of energy per cycle, and expressed in cycles per kWh. The higher the EF value means a more efficient equipment. It is the ENERGY STAR energy performance metric. This factor may vary based on equipment features such as water heating boosters or truncated cycles. The federal EnergyGuide label on equipment shows the annual energy consumption and cost, which use the energy factor. The EF does not appear on the EnergyGuide label. Unlike annual energy use, the EF does not take into account the estimated annual energy use in standby mode. The energy factor for a dehumidifier is calculated by dividing the water removed from the air by the energy consumed, measured in liters per kilowatt hour (L/kWh). None
Energy recovery 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 air flow mass imbalance between the two airstreams, as a percent of the potential total energy that could be recovered plus associated fan energy. None
External quantum The external quantum efficiency of a solar cell is the percentage of photons that are converted to electric current when the cell is operated under short circuit conditions after the reflected and transmitted light has been lost. None
Fill factor The fill factor is the ratio of the actual maximum attainable power to the product of the open circuit voltage and short circuit current. None
Heat recovery Efficiency of sensible heat recovery in percentage. None
Idle energy rate Idle energy rate represents the total idle energy consumed by the machine including all tank heaters) and controls, or while maintaining at a stabilized operating condition or temperature such as a thermostat(s) set point during the time period specified. Booster heater (internal or external) energy consumption should not be included. It's measured while equipment is enclosed. Also called standby energy rate. For cooking equipment, the purposes of the idle rate can be normalized based on the area of the (bottom) cooking surface. None
None None None
Not applicable Not applicable None
Off cycle heat loss coefficient The heat loss coefficient to ambient conditions. Btu/h·ft2·°F None
Other Other None
Power usage effectiveness PUE is a measure of data center infrastructure efficiency, representing the amount of energy that is needed per unit delivered to IT equipment. It is computed as the total annual source energy divided by the annual IT source energy. None
Rated sensible heat ratio The fraction of total energy transfer between the evaporator coil and air that is associated with sensible capacity (change in air temperature) expressed as a dimensionless value. None
Recirculation energy loss rate Rate of heat loss from the recirculation loop when operating. None
Recovery The ratio of energy delivered to heat cold water compared to the energy consumed by the water heater, as determined following standardized DOE testing procedure. None
Reflectance Reflectance is the ratio of the energy reflected from the surface of the interface to the total incident energy. There is a reflection of light at the interface between the first layer of a solar cell and the incident medium, usually air, and there is also reflection at the interfaces between the individual layers within the solar cell. All these processes result in a total reflectance between the solar cell and air. This means that a part of the incident energy that can be converted into a usable energy by the solar cell is lost by reflection. None
Thermal The efficiency of heat transfer between the combustion process and the heated steam, water, or air. (0-1) None
Unknown Unknown None
Water factor 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 is. The equation is: WF = Q/C. WF is the ENERGY STAR water performance metric that allows the comparison of clothes washer water consumption independent of clothes washer capacity. None
Term ID: 0c7a8485-8b74-49a4-b063-6ce3ff0c6155