In most German apartment buildings with central heating, a small meter sits on each radiator, the Heizkostenverteiler. The consumption part of each household’s heating bill is calculated from it. The rule behind it is the heating cost ordinance, introduced in February 1981 to save energy.
The ordinance requires that at least 50 and at most 70 percent of the cost of central heating be billed by measured consumption. The rest is shared by floor area.
A household that heats less pays a smaller share.