Yes, you can camp in your nuCamp trailer during freezing temperatures although you would have to dry camp (tanks are empty). The TAB, TAB, TAB 400, and AVIA as well as the Cirrus 720, are not four seasons campers (tanks are not sealed and insulated), the 820 and 920 Cirrus truck campers are four seasons. The Alde system will still heat your unit as long as it is in bypass mode.