How do I know if my house needs additional insulation?

Not every house needs more insulation, but there are clear signs to look for. If you feel drafts, cold walls when you touch them, or your heating bill shoots up without any obvious reason, you probably do need it. Also check if the ceiling or exterior walls have condensation, or if there are big temperature differences between rooms; that means heat is escaping or cold air is getting in uncontrolled.

Avoid making big changes without first checking where the heat is actually going - sometimes the culprit isn't insulation but a broken window or old caulk that you can fix for almost nothing.

A trick that works well: if you have a smartphone with a thermal camera (some models come with it already or there are apps that simulate it), take photos of the walls from inside when it's cold outside, that way you see exactly which areas are losing heat. In my kitchen I found that half of a window frame was shot, and I thought I needed to insulate the whole wall when really I just had to replace the caulk.