Seasonal heat loss from aggregate UA calculator

An aggregate UA represents all included envelope components at the stated boundary.

Units

Q_{\text{loss}} = 24 \times \mathrm{HDD} \times \mathrm{UA}

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

Given

Q_{\text{loss}} = 24 \times 3700 \times 820 = 72{,}816{,}000

Symbol	Meaning	Unit
$Q_{\text{loss}}$	seasonal transmission loss	Btu
$\mathrm{HDD}$	heating degree days	°F·day
$\mathrm{UA}$	sum of component conductances times areas	Btu/(h·°F)

Symbol	Meaning	Unit
$Q_{\text{loss}}$	seasonal transmission loss	kWh
$\mathrm{HDD}$	heating degree days	K·day
$\mathrm{UA}$	sum of component conductances times areas	W/K

Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.