Heating methods that increase air moisture (bathtub, humidifier) might encourage mold growth and condensation damage. Regularly check behind furniture that's standing against outside-facing walls, and around windows.
Be aware that the more you seal off air circulation to the outside, you increase the possibility of a dangerous buildup of carbon monoxide in the air. Be sure to install a carbon monoxide detector if you don't have one already. If you do, test it on a regular basis.