I'm struggling with planning the AC situation for my next 12 light setup as it will be in an area that can get to -10F or colder in the winter months. Most condensers on mini splits I've seen are rated to 5F minimum operating temp. I'm quite certain I'll have freezing problems if the condenser is outdoors. I plan on running the main room sealed with co2. The only option I've been able to come up with is to build an insulated micro closet near one of the rooms windows and insert a plywood piece in a portion of the sliding window (with a bar in window to prevent entry, of course) and cut two holes for exhaust and intake.

I know a lot of you out there are growing in freezing climates. I'd appreciate any and all input/suggestions/examples on how you're dealing with AC in these environments. Thanks in advance.