Putting a rug or rugs on the floor will help, but you can do more.
According to the Energy Saving Trust, insulating underneath the floorboards on the ground floor (only rooms above unheated spaces need to be insulated) can save you around £60 annually.
Some suspended floors can be accessed from underneath (if there’s a cellar, for example), but if this isn’t possible, you could take up the floorboards to fit insulation. The downside of this is that it’s a big, disruptive job and you may break some of the boards or not be able to get them up.
You can also fill the gaps between the boards, which seems the obvious way to stop the draughts. However, walking on the floor is likely to dislodge at least some of the filler, so it could be a waste of time in the long run.
If a room has a concrete floor, this can be insulated by fitting rigid insulation and then chipboard on top. The problem with this is that you have to remove the floor covering first, and the level of the floor will be higher, which may cause problems with the skirting boards, sockets and doors.
Another big job is making your home’s windows less draughty and more energy efficient, especially if you live in a period property that has the original windows.
Replacing windows is expensive, typically costing several thousand pounds for a house, but it is worth doing if you can afford to - the Energy Saving Trust says that swapping single-glazed windows for B-rated double-glazed ones could save you around £165 annually.
Remember that double-glazed windows don’t have to be made of UPVC - unless you live in a listed building or on ‘designated land’, such as conservation areas, where there are stricter rules about replacement windows (and doors).
If you can’t afford to change the windows, or at least the glazing (sometimes you can replace single glazing with double glazing, or fit special heat-retaining glass to the existing windows), there are much cheaper ways to make windows more energy efficient. These include fitting secondary glazing units or film (clear film you fix in place with tape).
Another good DIY option is weatherstripping, which is draught-proofing tape that helps to fill the gap between the frame and the window’s moving parts. Original sash windows are notoriously draughty, and weatherstripping can make them less so, but consult a good DIY book or website to see how to apply it to sashes, or get a pro to do it, because it’s more complicated than with other types of window.