For those in cold climates, how are you keeping your house warm frugally?
We were lucky enough to get a solar hot-air panel for our upstairs, which I've written about before. It's not a full solution, but it helps to keep the chill off up there when the sun is shining. We also switched to a woodstove (the stove was a Freecycle find but we had to pay for installation...that was not cheap, and I had help from family to make it happen, but it will more than pay for itself.) Here in the Northeast, dry cordwood for heating is still abundant and cheaper than oil for heating.
We have an oil furnace and a full tank of oil, but since the woodstove was installed, we've not used the furnace except for three times when we had overnight guests who were not accustomed to sleeping in lower temparatures. Even on cold nights (teens-20s F) the early-morning temp in the bedrooms has been around 55F, which feels like a perfectly reasonable sleeping temperature.
Sometimes I'm reminded that most families still use "central" heating...but my kids have adjusted and they don't complain (now that they're equipped with very warm bedding, socks, thermal underwear, neckwarmers, fleece footy pajamas, and hats). This has become "normal" for them at our house. Though it's true, we would do better to have overnight guests in the non-heating season!
My next challenge for myself will be to use the free cooking properties of the woodstove when it's already hot, rather than turning on the propane (gas) stove.
I am finding that even with new double-paned windows, the window coverings (shades and curtains) keep some cold out of the rooms; when I open them in the morning I can feel the accumulated cold air. We also have draft dodgers at the base of interior doors leading to unheated rooms (i.e., the pantry and a storage room).
What are you doing this winter to make the most of your heating budget and keep your costs low?