A large portion of the United States is experiencing the same type of temperatures today, so I decided to share a few things we are doing to keep warm.
Obviously, if you have a fire place or wood stove - use it. I'm going to talk about things you can do in addition to your normal heat source.
One thing we did shortly after moving into this home was purchase thermal curtains. We bought them from our local Wal-Mart for $24 because we have really crappy windows that let a lot of cold air in. This is a pretty common problem, especially with older homes. The curtains are a pretty inexpensive fix and makes a huge difference in comparison to brand new windows.
When it is cold, day or night, we keep those curtains closed to block out the draft.
Another inexpensive thing I did was make a couple simple draft stoppers. See here how I made them. I put them along the bottom of every external door and many windows.
Blankets aren't just for your bed. If you don't have thermal curtains, you can always hang them over your windows to block out the cold. Another option is to lay them at the base of your windows or doors. Anything you can do to stop the cold air from coming in and letting all your heat escape.
Of course, you also want to keep some blankets or quilts for your bed or for covering up with when sitting on the sofa.
Even while you are home you want to dress in layers. You don't want to crank up your heating system, raising your electric bill and putting a strain on the power grid. Keep your home set at a slightly cool temperature. You should be comfortable in a sweater or sweatshirt - not t-shirt and shorts in the middle of winter.
I try to keep busy, by cleaning my house or other errands when it's really cold. That way I'm too busy to realize it's cold.
If I must go outside I definitely wear a hat, warm coat, gloves and scarf. I try to cover as much exposed skin as possible. Dress in layers with long underwear, multiple shirts, etc.
One last tip, if you use hand warmers (the little sachets) place them directly in your pocket not directly on the palm of your hands. It will keep your entire hand warm in your pocket and also your hips a little as well. I you need to have your hands free, place the hand warmer on the top of your hand within the glove, not the palm of your hand.
Most importantly, only go outside if you absolutely must. Stay safe. :)