A great deal of energy can be lost through the floor of a ground-floor flat if the basement is not insulated. After insulating the basement ceiling of the multi-family house in Ludwigshafen, the floors are now warmer and the tenants save energy.
"There are clear benefits in the greater living comfort for the ground-floor flats—the floor is significantly warmer. Insulating the basement ceiling additionally contributes to overall energy savings: the tenants benefit from lower energy costs."