Cold climate ventilation question

Hi everyone, Just wondering what you growers who live in cold climates do in the winter for intake air? My room is 12x24x8 and would probably get cold pretty fast drawing in the cold air from outside when the lights go out . I have a 3 ton A/C-heating unit but think it might be hard for it to keep the room up to temp. Also my target temp is 75 degrees,
does that sound about right? Thanks

In the winter my house is set to 75 so no for intake from out side. Do u have a tent or are u using the whole room?

Last winter I kept all windows closed in the house and vented the 3k into the house for heat. I supplemented in the mornings with a gas fireplace, but I didn't even use the furnace last winter.

Jakeman. I like your idea of venting your waste heat back into your house. It seems like a waste to just dump the grow room heat outside when your furnace is working overtime to heat your house. Keep in mind, you're going to need to carbon filter the exhaust if you're dumping it back into your house. In the below thread, I posted some equations that may prove useful. Good luck bro.

https://www.rollitup.org/grow-room-design-setup/545602-how-much-heat-does-600-a-2.html