Room Heat Loss Calculator
Construction & Home ImprovementEstimate a room's heat loss from its wall, window, door, floor, and ceiling areas, insulation level, and indoor/outdoor temperature difference.
Heat Loss
Estimated total heat loss through the given surfaces, in watts, at the given temperature difference.
Heat Loss (BTU/hr)
4,643
The same heat loss figure converted to BTU per hour.
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Creators
Odeh Ahwal0people find this calculator helpful
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Saved
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Construction & Home Improvement calculators
Frequently Asked Questions
What do the insulation levels mean?
Poor represents an older, largely uninsulated building, average represents a typical existing home with some insulation and double glazing, and good represents a modern, well-insulated building meeting current standards. Each level uses published typical U-values, a measure of heat loss through a surface, for walls, windows, doors, floor, and ceiling.
Why enter both floor and ceiling area?
Ground floor and top floor surfaces lose heat to the ground or the roof space and should be included when they apply. For a middle-floor room with conditioned space above and below, enter 0 for both, since there is little or no heat loss through those surfaces.
What outdoor temperature should I use?
Use a local winter design temperature, the outdoor temperature your heating system should be able to cope with, rather than the coldest temperature ever recorded. Local building guidance or a heating engineer can provide the right design temperature for your area.
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