Heat Lost Around Doors and Windows

Hopefully your windows are reletively new and are made up of double panes with argon gas between them and were properly installed with the right sealant along the flanges.
In any event you need to check around the edges of both windows and doors for drafts, which means airflow and that is heat loss.
A cigarette or stick of insense will show air either coming into the house or going out of the house, just follow the smoke.
Once you have found the drafts you will need to fill them to stop that flow of air. Large gaps and cracks can be filled with foam products in a can or weatherstripping in rolls.Caulking is another good product, you will need a caulking gun and also need to match up the color of what you are sealing.
Don't forget to check under the door, there are thresholds that stick on and screw on the bottom of the door.
So chase down those drafts and save money on your heating bills.The products mentioned in this post are available at home improvement stores such as Lowes or Homedepot, hardware stores, as well as Walmart and other department stores.