How to identity cost effective ways to cold proof an old house?

See if anything in these links will help you out.

https://www.thisoldhouse.com/ideas/winter-weatherproofing-tips

https://www.oldhouseonline.com/articles/7-insulation-tips

http://www.onecrazyhouse.com/drafty-house/

Cover the windows with the 3M window systems, it is cheap and works. Get or make the cute sand bags to put at the bottom of doors. Use the foam tape to close up the gaps around outside doors. There are thin foam sheets you can put behind outlet covers to stop cool air from coming out of them. Carpet runners on cold floors where you walk the most helps. See if you can find some of the areas where the cold air is coming in and see if you can seal it from the outside. I hope this helps! Lived in a turn of the century house for 15 years and these are some of the things that I did.

When we lived in a camper in Wyoming cold winters, we found bubble wrap on the windows cut our heat bill down considerably. WE still bubble wrap our windows not in use in winter (spare bedrooms, hallways etc. Our heat bill is very low. We did leave 4 inch vertical open space on the windows or the very top on low windows to be able to see out. Weather strip all the doors, pipes, and put down rugs. If you can, have it re-insulated in the attic and walls.

You can get a free energy audit from your local power company who will use a thermal camera to show you where you're losing heat/energy.

Since I own a 75 yo home, here is what I did....

Caulk every crack, hole, crevice you can find and your windows. Add storm windows if you have old windows, or use plastic liner kits for winter.

Hang thermal curtains or cellular blinds to hold heat in to one of your biggest energy losing areas... the windows. You can also add reflective non-adhesive window film to windows to save energy.

Make sure all your doors have energy strips around them to prevent drafts and heat loss.

If you have a ceiling fan, reverse it for winter, flipping tiny switch so the warm air blows down into room.

If you have an uninsulated wall area, insulate it, they didn't use to insulate closet areas. I did.... added rigid foam to outside wall of closet, painted to match.

If its really cold, add more insulation to your attic.... blow-in or fiberglass batts.

If you feel cold from floor, consider insulating your crawl space, and under your floor joists. I also put pieces of plywood over the basement vents during cold winter months.

Any thing that would add another layer over the windows would help. Putting blankets over the doors may be more hassle than they are worth except for doorways to other rooms. Outside doors you would be better off using the foam strips, etc. that wouldn't get in the way of opening and closing the doors you use. If it is a door that is never used, not a bad idea. If you add the fireplaces, make sure that you have a good way to exhaust the fumes out with the gas so you don't get carbon monoxide build up in the house. Electric should work, but may drive the electric up a lot. Do what you have to do to warm up the house, just be safe in how you do it to prevent health problems.

WE have a double velvet curtain that hangs in front of our front door, year round, except we only pull it over the door in the wintertime. The window behind the clock shown here has house window, storm window, shutters and over the house window we have fastened plastic, held in place by the window stops. This is not really visible. The curtains in our sitting room have fleece blankets as liners. I just use T pins to pin in place and flounce on curtains hides the pins. This gives a lovely weight to the curtains too. In the room we eat in, we had the radiator taken out as we did the small kitchen radiator too. So we got a fake stove at a yard sale ($25) and use that in the winter for when people come to play a game and for when we eat. We also bought a fake radiator at another yard sale and use that in our sitting room when we watch t.v.

A huge waste of heat is through our back door, which opens into a small hall that has a toilet off it. I have wracked my brain over how to prevent the cold coming in and we can't use a door curtain here. But I thought of hanging just screw in hooks in strategic places and hanging some of our many down coats on them. That should block a lot of drafts, but I've yet to do it and we are thinking of replacing our storm door here. It is just try everything you can think of that is safe as Nancy says.