# The ALF-value calculation

ALF-value is a measure of thermal heat losses and warm-up energy required.

Entering a location in ALF automatically selects the coldness of climate and length of heating season/heating energy demand. These factors are described by the annual loss factors value (ALF-value). Colder climates (and higher heating levels) have bigger ALF-values.

Specifically, ALF-value is a measure of thermal heat losses and the warm-up energy required:

ALF-value = hours x °C x 1000.

One ALF-value exists for each climate, heating schedule and heating level.

The energy lost through a building component is calculated by multiplying the specific heat loss with the ALF-value.

For more information, see the Climate and heating topic in the Manual.