Nowarski Engineering: New Technologies for Green Development: Energy Efficiency, Renewable Energy, GHG Mitigation
selection of room air conditioner (AC) (v304)

by no means do not use this calculator for actual purchase of air conditioner

this calculator is for typical buildings in Israel and does not apply to USA buildings
enter or change a number in any field with frame, all the rest will be recalculated automatically
region: the hottest month average temperature [C]:
thermal insulation:
room floor area, m2
room floor area, SqFt
cooling capacity, W
see notes to the right
cooling capacity, BTU/hr
see notes to the right
Coefficient of Performance - COP for cooling
electric power, W
compressor size, HP
this is not relevant to the AC selection
30 years ago, this was the way to determine the size of AC, but not today
Cooling load depends on many parameters and may vary between 100 to 300 W/m2.
some parameters:
  • apartment floor, under the roof, middle floor
  • construction materials, kind of insulation, its thickness and location
  • windows geometry and shading arrangements
  • windows and shutters material
  • ventilation (windows opening) habits
  • room orientation
  • solar radiation gain
  • geographic region
  • indoor heat sources and humidity sources
  • neighboring rooms temperature

  • electricity consumption calculations
    working hours of air conditioner, hours/year
    electricity tariffs, cent/kWh, including VAT
    electricity consumption, kWh/y
    electricity consumption, $/y
    justified additional investment in 0.1 better COP [$]

    by no means do not use this calculator for actual purchase of air conditioning

    this on-line calculator is for general information only,
    it does not include many components
    and must NOT be used for actual design, or economic evaluation, or decisions about the project

    link to much more detailed Air Conditioning calculator (in Hebrew, locations in Israel only) -
    e-mail: [email protected]
    (c) Nowarski Engineering: New Technologies for Green Development