A wooden door retains heat better. Wood has low thermal conductivity, so the wood itself barely heats up from the inside and produces no heat
A glass door generates more heat and requires more powerful heaters to ensure consistent heat loss
Ideal option in our opinion in a wooden door with a glass. A strong wooden door creates an effect of solidity and strength. Wood is safe and will not burn your skin, but glass allows to look outside and safely open the door without accidently hitting anyone