I'm talking about modern, sealed, double-glazed housing. Older housing was much more permeable, so moisture (and unfortunately heat) could escape to the outsid

I'm talking about modern, sealed, double-glazed housing. Older housing was much more permeable, so moisture (and unfortunately heat) could escape to the outside air at will. I'm sure that the cost of running a dehumidifier is at least as low as the cost of running your heating more frequently because of heat loss.