EER:
Energy Efficiency Ratio
EER = COOLING CAPACITY in BTUh / POWER INPUT in WATTS
The higher the EER rating the more efficient the equipment is.
SEER:
â??Seasonal energy efficiency ratioâ?? defined as the total cooling output (in British thermal units or Btu) provided by the unit during its normal annual usage period divided by its total energy input (in watt-hours) during the same period.
C.O.P:
Coefficient of performance
The ratio of useful energy of a machine to total energy used to obtain it. All terms must have similar units. i.e. use KW for both useful and total energy used. Air conditioners have a COP of 2.8 or higher.
Therm:
One therm is 100 cubic feet of natural gas. A safe assumption is that 100 cubic feet of natural gas provide 100,000 BTU.
Economizer:
Air side economizer is a set of dampers that allows an air conditioning unit to use cool outside air for cooling, and exhaust building air.
Waterside economizer is the use of water cooled through cooling towers to cool return air. An additional coil is needed upstream from the mechanical cooling coil. Unlike air side economizer, waterside economizer requires extra piping, coil and evaporative cooling. Therefore, its payback is much higher than that for an airside economizer.
An R-value is a measure of insulating power or ability to resist the flow of heat. Higher R-values mean greater insulating power, which means greater household energy savings and greater cost savings.
U-values rate the energy efficiency of the combined materials in a building component or section. For example, in a typical insulated wall you have the dry wall, the insulation material, the wood frame, the exterior and interior air films, and the exterior finish of the wall such as stucco. Because each of these components works together as a unit, the U-value is used to indicate the energy efficiency of this entire assembly.
U-value = 1/R-value
The smaller the U value the more efficient the material.
