Cooling Load per Room
Estimate cooling load from room size, sun and occupancy.
About Cooling Load per Room
Cooling load combines the room's heat gain through walls and windows with heat from people and appliances, each converted to BTUs and summed. A room's AC needs depend on more than area, so adding occupancy, sun and appliance heat gives a load the plain area rule misses.
Formula
Cooling Load per Room
Total = (area x 15 + watts x 3.41) x sun factor + people x 500
- sun factor
- Boosts load on sunny exposures
Worked example
With the default values below, Cooling Load per Room returns Base Load of 6,205. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Room areaminimum 0 sq ft
- 300 sq ft
- People typically insideminimum 0
- 2
- Sun exposureone of Shaded, Moderate, Full sun
- Moderate
- Heat from appliancesminimum 0 watts
- 500 watts
Results
- Base Load
- 6,205 BTU/hr
- Occupants Load
- 1,000 BTU/hr
- Sun Bonus Factor
- 1.10
- Total Cooling Load
- 7,826 BTU/hr
Step by step
- 1Values used
- 2Cooling Load per Room
- 3Base Load= 6,205 BTU/hr
- 4Occupants Load= 1,000 BTU/hr
- 5Sun Bonus Factor= 1.10
- 6Total Cooling Load= 7,826 BTU/hr
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Cooling Load per Room calculated?
Total = (area x 15 + watts x 3.41) x sun factor + people x 500 Cooling load combines the room's heat gain through walls and windows with heat from people and appliances, each converted to BTUs and summed.
Why does Cooling Load per Room matter?
A room's AC needs depend on more than area, so adding occupancy, sun and appliance heat gives a load the plain area rule misses.
What values do I need to enter?
This calculator takes 4 inputs: Room area, People typically inside, Sun exposure, Heat from appliances. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.