Construction Heat Loss Calculator

Estimate the heat energy loss of a room or building through its surfaces.

Room Parameters

Surface Area (sq ft) (sq ft)

Inside Temp (°F) (°F)

Outside Temp (°F) (°F)

Insulation Quality

Heat Loss Estimate

Enter temperature and area data

Overview

Heat loss occurs whenever there is a temperature difference between the interior and exterior of a building. It's primarily driven by the 'thermal bridge' of walls, windows, and ceilings. Calculating this is crucial for sizing heaters and boilers correctly.

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Pro Tips

A common residential rule of thumb is 30-50 BTU per square foot of floor space for total heating capacity.
Upgrading from mediocre insulation to modern standards can reduce heat loss by over 70%.
Don't forget to calculate heat loss through the floor if it's over a crawl space or slab.

Fun Facts

"The U-value (thermal transmittance) is the reciprocal of the R-value (U = 1/R)."
"Windows typically account for up to 25% of a building's total heat loss."
"Heat loss also occurs via air infiltration (drafts), but this tool focuses on 'conduction' through surfaces."

Formula: Q = U × A × (Ti - To)

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