Heat Loss Calculator

Estimate building heat loss in BTU per hour based on envelope area, insulation R-value, and temperature difference.

sq ft
degF

Total Heat Loss (with infiltration)

11,538 BTU/hr

Conductive Loss9,615 BTU/hr
Estimated Furnace Size20,000 BTU/hr

Total Heat Loss (with infiltration) vs Envelope Area (walls + ceiling)

सूत्र देखें →

सूत्र

## Building Heat Loss **Q = (A / R) x DeltaT x Infiltration Factor** A is the total building envelope area through which heat escapes, R is the insulation R-value, and DeltaT is the temperature difference between inside and outside. The infiltration factor (1.1 to 1.5) adds losses from air leakage.

हल किया गया उदाहरण

2,500 sq ft envelope, R-13, 50 degF difference, 1.2 infiltration.

  1. 01Conductive = 2500 / 13 x 50 = 9,615 BTU/hr
  2. 02With infiltration = 9,615 x 1.2 = 11,538 BTU/hr
  3. 03Furnace size = round up to 20,000 BTU/hr