Around a third of the heat lost in an uninsulated home goes straight through the walls and a quarter goes through the roof.
By insulating your walls and loft, you will improve the comfort of your home and reduce your heating bills.
From the 1990s onwards, houses were insulated as part of the construction process. However if your home was built before that, it probably has no insulation at all. If it was built after about 1920 you will probably have cavity walls; if it’s older than that it’s likely to have solid walls and would benefit from solid wall insulation.