I never noticed how humid it gets in my detached garage. I started noticing more that after not being driven for a while the brake discs would develop light rust. Then I had some tools starting to show some signs of rust and finally, part of the exhaust one day was wet (in mid winter) and starting to rust.
I needed a dehumidifier.
I’d recommend anyone get one for an uninsulated garage like mine. Did a bunch of research, if you are using it outside you need something called a ‘Desiccant dehumidifier’ – a normal cheap household dehumidifier can often be a ‘Refrigerant dehumidifier’ but this type won’t work at the low temperatures you can get in your garage. So if you have one already, check what type it is – nice summary here.
After some research I opted for the Ecoair DD3 Mk2 10.5L/day Desiccant dehumidifier.
You can purchase direct on ecoair.org or via amazon – those links are to the Mk3 version (Mk2 seems no longer available) – please note as always if you do use the amazon link I earn a small commission (no impact on amazon price you pay). Other brands and models are available, but I have had great results with this one. I leave it running around the clock, set the target humidity for 60% and empty the tank anything from once a day to once every 4-5 days. You can also plumb it to run a pipe through a hole in the wall so you don’t have to empty the tank manually (I haven’t done this yet). I also try to air the garage out wherever possible. This does use some power so just bear in mind power consumption.
After having it for 6 months I wouldn’t be without one for the garage now – its not just the car, its the bikes, the tools, everything. Highly recommend, and wish I had it when I started my build.