I have eclipse brand thermal curtains. I bought mine a few years ago and boy have they helped. I close them at night and keep them open in the afternoon, to let the warming sun in. I have levolor brand thermal shades on every window facing west on our house, to help cut the summer sun baking our house all afternoon. That seems to help in the winter as well, even if it's just a barrier to cold. We install small bubble wrap in every window we don't need to see out of in the cold weather. Seriously, it really helps. We have double hung windows, from '95, and they are just awful. Spray a little water on the window and place bubble wrap (bubble side to the window) and bam, you have an instant layer of insulation on those freezing cold windows! This is our first year trying out the Mortite brand caulking rope. It's sort of like clay, and I stuffed it into the edges of all of our downstairs windows, where the windows meet the frame. I have aluminum windows, and every one is crooked. Thank you lovely builders. Since I don't have $20,000 to replace the 26 windows in our home, I instead seal them shut through the cold weather. It works for us! I will say I put the Mortite in and the bubble wrap up yesterday, and felt a huge difference coming downstairs this morning. Yesterday I froze, today it's pretty nice, and the temperature has been 36 to 37 both mornings! I feel victorious ;)
Last year we replaced our patio doors with sliding glass doors, and that made all the difference in the world to our temperatures downstairs. The patio doors were old, crooked, and leaked terribly. $600 later our sliders are more air tight than we could have dreamed of! We also put in new weather stripping on the two exterior doors, and put in new sweeps on the bottom. The front door is so crooked (frame as well) that until we can replace it I keep it locked tight all winter and hang a quilt over the entire frame. It's ghetto but helps. We put in a storm door, it helps a little, but cold still pours in over the top, side and bottom of the door. Again, awesome builders!
We have gone through the entire house using Great Stuff and sealed all the gaps around pipes, vents, etc. coming in from the outside. Last year we also realized there was cold air POURING in under our mopboards on every exterior wall. So I got sick of freezing cold feet and pulled the rugs back a little, sprayed Great Stuff under the mopboards to seal it tight, and put the rugs back when it dried. I had to cut the excess off, and if you look hard it does look trashy, but I tell you what my feet stay warm. Why the heck would the walls leak cold air under the mopboards?!!
Hopefully I have inspired someone to stay a little warmer this year, maybe save a few dollars on their heating bills. Our big project we are trying to get to before the new year is insulating our eaves. Our bonus room is over our garage, and has slanted ceilings. Some idiot created little "cubbies" of sorts where the ceilings got too low, and never insulated the cubbies. At all. So the walls of the room are uninsulated, and part of the ceiling is uninsulated. It's about 40 outside right now, and I guarantee that room isn't warmer than 50 right now. We might as well leave a window open in there, it has the same effect! So we bought two rolls of insulation, and plan to install it this month. I really hope we have time to get it done!!!