Make sure your windows allow the sun in. Invest in double windows and well insulated walls, and your home will be pleasant all winter long, except when it rains and the sun is hidden by clouds.We didn't use any special materials, and almost all of our windows face the east and south. When the house was full of kids and guests it did seem warmer than most. In those days most of our neighbors had less efficient heating and insulation than we did, so the house was more comfortable in the winter. But over the years they invested in more heating appliances. Also, those books I read mentioned nothing about the strong winds from the south in the winter.
Now our house is very empty and cold. I think it's connected. For the past few years, we've been heating with electric, oil-filled radiators. I now keep one on low in the living-room all the time, so the room doesn't cool off. We skipped all sorts of heaters and heating system fads that others have invested in. The popular one nowadays is the heater-air-conditioner combo. Hot or cold air blows around the room. It's OK for cooling, but I don't find my body heated by it when I'm in homes that use it. It dries out the air and respiratory system which can be dangerous. Israeli tile/stone floors stay freezing cold, unlike when you heat with a radiator. Within a short time off it gets cold, so the machine keeps switching on and off, and you can hear it. Our radiator stays warm for a while after being turned off and is totally silent.
I guess my house would feel warmer if I had a rug in the living-dining room, but then I'd also need to invest in a vacum cleaner. All this would cost money, which we don't have. Would we need to spend less on electricity for heating? And cleaning wouldn't be sweeping and then "sponja," the Israeli wet-mopping floor-cleaning method/system.