Short of winning the lottery we're doing ok with dehumidifiers and airing the place out for now. It's amazing how many problems can be fixed keeping the place well aired.
Tiny evolution of my 'dehumidifiers fix everything' manifesto.
Got a timer plug in a charity store because while I never sleep anyways, listening to it at night was annoying. Running 9.30* to 2300 ish and it still is maintaining the place well enough.
Got one of these hygrometers just to get an idea what it actually does, which has largely taught me that I like it to be about 18 degrees and about 67 humids in the house. In summer i just put the dehumidifier in the high 70s as the windows were open, and when they were closed at night it would rarely switch on at all.
I assume damp air is harder to heat so besides not living with spores there might be a small energy return there. Might learn about that later for the craic.
*peak electricity usage rolls off around this time, there is no saving for me but there is a microscopic advantage in not using background devices like this during peak times.