When buying a garden room, whether to be used as an office, a snug or as an outdoor room for entertaining, it needs to insulated well enough to be useable on the coldest winter day, or a hot summer day.
The type of insulation used is key to ensuring the building delivers what you need. Our preferred construction material would be 75mm PIR on the walls and floor with 150mm PIR in the roof.
With less than that, or different materials you are likely to have to install higher output heating sources which will increase the energy use and running costs.