But first thing you have to think about is your windows. Possibly you got, vintage, wooden ones? They are looking very nice, likely, but it is not enough. When you will exchange it for some new, PCV pieces, you should have a chance to keep plenty of warm air inside of your rooms. You do not need to replace every piece at ones, you may do it in couple steps, to avoid too much expenditures in one season. Different relevant case is your roof. If you will cover it with some fibreglass mesh, it would also keep your home a lot warmer in the time of winter, cause a lot of the air is escaping trough it, probably.
Next, you may invest some of money in external wall insulation. It should be very huge cost, but it is worth it, more information here – external paints. Within several years, costs of it should come back to you into the warming expenditures. Also, when you wish, you could at the end make some interior insulation as well, exerting also fiberglass mesh – it is the nicest product for all this type of works. But where you could buy all the materials? It is really easy, go to the nearest building department. You will find there all the stuff you need, from screwdrivers to fibreglass mesh.
If you are scared of cold season, thanks to big expenditures for healing, there is a fine solution. You must to arrange an external wall insulation and exchange vintage windows with PCV ones, more – fibreglass mesh. It should help you to spare plenty of money, and it is great for environment, cause you would waste much less energy. And the nicest season to begin renovation like this is summer. So possibly you may consider it?