You haven't mentioned it, but with weather sometimes at -30* in your area and an attached garage, I imagine you likely have at least some heat in the work area. Pulling even warmish humid air (from car snowmelt) out of the garage through gravity louvers with -30* outside will likely condense and freeze on the louvers and probably make them stick in the open position. If you're working on carbs or using smelly cleaners every day, then some action to remove the smell might be wise but installing an exhaust fan for occasional carb work is an overkill. I would think you have a far more serious problem with condensation all over everything if you open your big doors when you have -30* very dry air outside and high humidity in the garage. If you want to extract 800 cfm from the space, that air has to come from outside, be it from an air intake opening or through infiltration around your doors and windows. Other guys from the cold northern states might want to chime in with their experience with the problem of trying to ventilate a shop during extremely cold outdoor weather.
Glen
Yes, heated floor in garage. 24x26 roughly. 9ft ceiling.
-30* would be rare, maybe 3-5 days a year we are around that. More usual is single digit negative temps and positive temps.
Gas/diesel, Painting, welding, grinding, sawdust, etc
When the temps are nice, no issue with having the doors open or even working outside.
Use a dehumidifier for snowmelt, but it's expensive to run. If it's not used, it gets very humid and the windows get iced over and the doors sweat too and freeze shut.
No floor drain which doesn't help. On septic and was told by builder it wasn't allowed.
Figure if it's running 10 hrs a day, that's about $45 a month in power. Don't think it'd cost that to heat the air with a vent fan.
HRV would take care of the heat loss, but they are expensive and aren't designed to flow air to clear fumes.
In my house I just have attic to heated space makeup baffles and 2 bath fans with humidstats.
Will put a makeup air baffle inlet if infiltration isn't enough.
