We have a wood burning stove that is very effective in our family room. We haven't had to use it for the last 3 years.
We have a fairly new and well insulated roof and about 1/3 of the house has new and very effective double paned windows. More will be installed this month. In spite of the insulation, new windows and other stuff, it has been colder than normal in N. California in October.
My hubby is a carpenter, he has installed double paned windows as well. The insulation is top notch. Winters here are fairly ok..sometimes it gets below 30.