If you need a warm cabin for all year round then there is only 1 real choice - the Twinskin insultated cabin. The cavity wall uses the same priciple as your house to keep the warmth in and the cold out.
Twinskin offices are 3-4 times warmer than a single skin cabin made from the same amount of timber (ie 35mm twinskin = 70mm single skin) because of the cavity in the wall, but at around the same price - the choice is simple and obvious! A small electric heater on minimal heat is more than enough to keep it warm enough enough for a gardem office even if there is snow on the ground outside!
Would you like to know more about our Twinskin insulated log cabins? Not just heresay etc but actual facts and figures, please use this link to "What is a real Twinsking log cabin".