1. Keep your doors and windows air-tight. Use the removable window-caulk or plastic to better seal them. 

2. Put up heavy curtains. A set of heavy curtains can block heavy drafts of air. Open them when the sun is shining and close them when it’s not.

3. Close off any unused rooms. The closed door makes that room another barrier between you and the frigid outdoors. It also stops air from circulating as much, which reduces heat loss.

4. Add insulation in the attic and the crawl space. A lot of heat escapes through the attic, as warm air rises and cold air sinks. Make sure that your attic has enough insulation.