i have to instal a water chlorination system in a shed b/c my house is a doublewide with no basement. will build a 4"x4" 7" tall shed with concrete pad. this is the easy part. what kind of insulation should i use. i want to heat the space with a light bulb or some other simple heat source. the house is in new york so it gets cold here. whats the best way to keep door seems tight also?
Also insulate under the concrete with rigid foam. Spray foam is probably the best in terms of keeping out air, and keeping in heat, but often pricey. Don't seal the interior completely, there should be some small vents high up.