Have you installed new windows? If not, you really should. That helped me a LOT. You may also try heavier drapes.

If your house was built in the '20s, likely there isn't much insulation in the roof/attic and you may not be able to just add some without rewiring, as it may still have knob and tube wiring. Most heat loss occurs through the ceiling/roof as heat rises and cold falls. Windows are the next biggest loss, and to get you through this winter, you can go to the hardware store and buy a roll of plastic and tape it over the windows. You might even want to cover the trim too, as there often are weight pockets beside the windows that are only covered with trim on both sides. My windows weren't leaking themselves, but they had been installed so badly that the walls and trim around them were leaking like a sieve. We took the trim off and sprayed Great stuff all around the windows, then reinstalled the trim. That helped more than new windows would have. There are also special kits with heat shrink plastic that you can put over windows, but they don't usually cover the trim too. The floor is also suspect in older homes, especially if heat is being lost through the attic. As the heat rises through the attic, it draws cold air from somewhere. In modern homes, there is a plywood subfloor. In older homes, there is often just barn boxing laid on a bias, then flooring laid perpendicular to the floor joists. Cold air can be pulled straight up through the gaps in the floor to replace what is going out through the roof. Also in older homes, particularly if they have been rentals, the utilities have been installed multiple times. The phone company and cable company, in their wisdom, rarely look for the hole where it was installed last time and use it again. They just drill another and another and another. Over time, this can amount to many holes in the rim joist, siding and floors. Great stuff or caulk or both can really help tighten that up. Its too cold to caulk right now, it won't stick and it won't cure, but if we get some warm days, get outside and replace the caulk around your windows and doors. That will help a lot too. Don't forget your chimneys. They are a big source of heat loss. Your heat rises right up the chimney and cold air comes right down it. Make sure your dampers are closed. If you aren't using the chimney and nothing is venting through it (like your furnace or hot water heater) you can always board over it. The last year we had I fireplace (before I tore it down), I stuffed the firebox full of 2" slabs of styrofoam and then bolted the doors closed so the wind couldn't pop them open. The thing was leaking badly, as it was built of interior grade bricks and water was getting into them and splitting them. It wasn't safe to use either, so I took it down the next summer, but the styrofoam got us through that winter without freezing. Just be careful to make sure nothing else is venting through it first, so you don't kill yourself with carbon monoxide poisoning.

you can weld down every crack in the house and staple blankets to the walls then set your kithen trashcan on fire that will be very warm

They sell window kits at the hardware stores designed for that purpose. They come with plastic and some kind of edging that you can either tape or tack to the sides and does a very effective job of keeping the drafts out and the heat in

If you are independently wealthy and dont mind spending the money replacing all the windows is one way. But even that may not be the problem. Fortunately every home improvement store sell weather stripping, caulk and foam insulation to fill in any and all area around the window box. all will greatly reduce the amount of exterior air from coming in. Inexpensive and effective, what more could you ask for?

PUT PLASTIC AROUND ALL WINDOW FRAMES AND TAPE IT. IT STOPS COLD AIR FROM ENTERING.