Efficiency Metric Qualifier

The measure used to quantify efficiency

Data Type: 
Constrained List
Unit of Measure: 
Commercial, Residential, Multifamily
List Options Option Definition Unit of Measure
AFUE Annual fuel utilization efficiency is a thermal efficiency measure of combustion equipment like furnaces, boilers, and water heaters. The AFUE differs from the true 'thermal efficiency' in that it is not a steady-state, peak measure of conversion efficiency, but instead attempts to represent the actual, season-long, average efficiency of that piece of equipment, including the operating transients. It is a dimensionless ratio of useful energy output to energy input, expressed as a percentage. For example, a 90% AFUE for a gas furnace means it outputs 90 BTUs of useful heating for every 100 BTUs of Natural Gas input (where the rest may be wasted heat in the exhaust). A higher AFUE means higher efficiency. None
COP Coefficient of performance - a measure of the amount of power input to a system compared to the amount of power output by that system. None
EER Energy efficiency ratio - the ratio of output cooling energy (in BTU) to electrical input energy (in Watt-hour). None
HSPF Like SEER, this is a measurement of the efficiency of a system and the units are the same (BTU/h divided by Watt). However, this measures the efficiency of the system in heating mode, not cooling mode. Therefore it applies only to heat pumps or reversible air conditioning units and not to units that only cool a space. None
IEER Integrated Energy Efficiency Ratio (IEER) - This measure expresses cooling part-load EER efficiency for commercial unitary air conditioning and heat pump equipment on the basis of weighted operation at various load capacities. Previously known as IPLV. None
kW per ton The efficiencies of large industrial air conditioner systems, especially chillers, are given in kW/ton to specify the amount of electrical power that is required for a certain power of cooling. In this case, a smaller value represents a more efficient system. However, to be valid, this number must be reported at various operating conditions, especially the indoor and outdoor temperatures, and the difference between chilled water return and chilled water supply. None
None None None
Not applicable Not applicable None
Other Other None
SEER Seasonal energy efficiency ratio - ratio of output cooling energy (in BTU) to electrical input energy (in Watt-hour). However the SEER is a representative measurement of how the system behaves over a season where the outdoor temperature varies. None
Unknown Unknown None
Term ID: 4af43a8f-ebba-442e-a670-9d12bc940fb6