It’s a no-brainer to insulate your home, and it’s important to consider every aspect of the house, including ventilation when your house is insulated and airtight. Start with the roof, where at least 350mm of mineral wool or natural fibre insulation should be used. Cheap fixes include draught-proofing old sash windows, doors and letterboxes, and using a chimney balloon to stop heat escaping. Close curtains and shut doors where rooms aren’t in use.
Wall insulation must be done carefully, because cavities in walls are designed to move moisture around and prevent damp. But natural insulating materials such as wool, wood fibre, cellulose and hemp have a much lower carbon footprint than fibreglass or mineral wool, and they have comparable thermal and sound reducing qualities. Companies such as ecomerchant offer natural building materials and advice. You can insulate cold walls with thermal wallpaper or blocks. If you have a suspended floor, you can insulate between the joists with natural fire-retardant material, and you’ll keep the sound out as well.
You can install double glazing for its heat-retaining benefits as well as security and reducing condensation, but the benefits are modest compared to other improvements. If you plan to insulate walls, upgrade your double glazing at the same time to prevent heat leaking around the windows.