Insulation is a type of work, wherewith the help of materials RKND creates a barrier to keep the warm air inside of the building. Insulation materials, that will be used, depends on the structure of the building and on the end goal.
Insulation, depending on the materials used, can be done on outside of external or inside of external walls. When insulation is done for the inside of the external wall, then space will become warm very fast, but it will also cool down very fast. When insulation is done for the outside of the exterior, then walls will have to warm up at first. So it will take more time to warm up the space, but it will take longer for space to cool down because heat will be released from the walls.