> dropping below 19 degrees during the winter will damage building and allow mold to grow.
Can you provide a source ? This would mean that all unoccupied houses would be damaged, since they are just heated to avoid freezing (10 ?).
Can you provide a source ? This would mean that all unoccupied houses would be damaged, since they are just heated to avoid freezing (10 ?).
Warm air can hold more moisture than cold air. Humans and their activities give off moisture. In winter humans maintain warmer than ambient temperatures. Therefore at some point the warm wet air is going to cool and reach its dew point.
Ideally you don't want this happening in the house, whether it does depends on the inside temp and the outside temp and humidity inside and out.
So there's a few knobs you can twiddle, temp being one.
They say 18 degrees, to avoid issue with moisture. It very much depends on how the home is built I'd assume, because holiday homes are normally kept colder, down to 5 degrees, during the winter.
The thermostat is now back up to 19.5°C.
But drywall (and other porous surfaces) are supposed to help regulate moisture, so if they never get an opportunity to dry because it's permanently cold and humid, yeah, that'll be a problem. Cracking a window at least 30 minutes per day (ideally on dry days) does wonders, though it won't help temperatures in winter.
In practice... say, there is a dog that likes to gnaw on corners and thus punctures the vapor barrier. Happened to my own house's outside insulation. That's just one of many "unforeseen" ways how these foils and barriers stop working. I fully expect the polystyrene there to get moldy in 20 years or even less.