We want to place the sauna partially outside with the door inside our garage. We would have the base and installation done professionally. will the 2 or 3 person cedar infrared sauna work this way? We want interior access but don't have enough room to fit both the sauna and the second car in the garage. Climate is Central New York, 90 degrees max in summer and about 10 degrees low in winter. We would have a proper roof and, if necessary, insulated shell constructed.
The infrared saunas are really only designed for indoor use.
Infrared does not perform well in lower ambient temperatures, below about 65 degrees F.
I think you would have challenges with what you described in your question.