Heat Transmission Loss Formula
The heat loss (expressed in Btu) of a given space is determined by multiplying the coefficient of heat transmission by the area in square feet by the design temperature difference (i. e., the difference between the indoor and the outdoor design temperatures). Because a heating system must supply an amount of heat equal to the
Amount of heat lost in order to maintain a constant indoor design temperature, heat loss is approximately equal to heat required. This may be expressed by the following formula:
Ht -where H =
AU(ti — t0)
Heat loss transmitted through a structural section (e. g.,
Roof, floor, ceiling) expressed in Btu per hour, representing
Both the heat lost and the heat required.
Area of structural components in square feet.
Overall coefficient of heat transmission.
Outdoor design temperature.
Indoor design temperature.