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0 of 6 steps completedStep-by-Step Instructions
1 Step 1: Calculate Square Footage
Step 1: Calculate Square Footage
Measure the square footage of all rooms to be cooled. Include hallways and closets in your calculation.
2 Step 2: Consider Ceiling Height
Step 2: Consider Ceiling Height
Standard calculations assume 8-foot ceilings. Adjust BTU requirements upward for higher ceilings.
3 Step 3: Assess Insulation Quality
Step 3: Assess Insulation Quality
Poor insulation requires a larger unit. Check attic insulation R-value and window quality.
4 Step 4: Account for Sun Exposure
Step 4: Account for Sun Exposure
South and west-facing homes need more cooling capacity. Add 10% capacity for very sunny exposures.
5 Step 5: Factor in Occupants and Appliances
Step 5: Factor in Occupants and Appliances
Add 600 BTUs per person beyond two occupants. Kitchen and laundry appliances generate heat requiring additional capacity.
6 Step 6: Get Professional Load Calculation
Step 6: Get Professional Load Calculation
HVAC contractors perform detailed Manual J calculations considering all factors for precise sizing recommendations.