In cold weather, insulation keeps heat in a building for longer, reducing heating demand. In hot weather, insulation keeps a building cooler for longer, reducing demand for fans or air conditioning. It can be applied to walls, roofs, and floors, and prevent draughts.

Enables: Biomass, Biogas & Biomethane, Heat Pumps, Solar Water Heating.

Insulation is material that transfers heat very slowly. Adding insulation to a building reduces the rate of heat loss or gain from the external environment. This means less energy is needed for heating or cooling to keep the building at a comfortable temperature. Insulation makes a building’s heating system more efficient, saving money on energy bills and reducing the amount of carbon dioxide (CO₂) emitted in the process of heating or cooling a building.

Reducing heat demand to keep a building at a comfortable temperature is especially important for low carbon-emission heating systems discussed in later sections. This can cut the payback time and return on investment for these technologies significantly by improving their efficiency.

The main kinds of insulation are wall, roof, floor, and draught-proofing. These are discussed below, as are the common sub-types and materials, circumstances each is applicable in, and external factors that should be considered such as the need for planning permission.