Our summerhouses are generally only designed for usage 6-9 months of the year. This is because the 11mm thick walls do not provide ample insulation to keep warmth in during the chillier months. You do have a couple of options, though - we offer thicker walls (up to 44mm) on our log cabin summerhouses, which means they keep a lot more heat in. Alternatively, you can install your insulation in your summerhouse - check out a guide on how to do that here.