Hi everyone, we have a mid century bungalow that is difficult to air enough. It smells bad, we really notice when we come home. Musty/damp smell. It seems to have got worse over a few years. We are careful not to leave wet clothes airing without a dehumidifier and open the kitchen door when cooking. We get some mould on outside walls sometimes (so have moved any furniture away), and lots of condensation on windows in the winter (which we wipe off then open windows). We don't heat it as much as we'd like due to cost and environmental impact. So the house is often pretty cold. If we open several windows wide for a few hours it smells fresher, but the smell comes back soon after closing them.
Trying to figure out what to do about the smell. The roof and gutters have been checked recently. We had one roof leak at one point but a surveyor has confirmed it is all dried up now (used a damp meter on the ceiling). I suppose there could be a leak somewhere else like under the floors (mostly carpeted), or maybe rain gets into the crawl space via vents (would that make the whole house stink?). DH says it didn't seem wet anywhere last time he went into the crawl space. There is insulation beneath the floors.
Any suggestions on A) finding out definitively if there is any kind of leak in the house; and B) whether something like EnviroVent/other mechanical ventilation with heat recovery would be a good solution for freshening the air and removing any mould issue. (I've read a few threads on the latter on here and people seem pleased with it, but would like to rule out any other source of the smell other than just a cold house with unchanged air).
Many thanks!