A building’s thermal performance refers to how well a building is insulated from external weather conditions. It is normal to think that insulation batts and reflective insulation are the only things to consider for your roof, but in reality the colour of your roof can influence the thermal performance of your house.
Light versus dark
Imagine you’re standing outside on a hot, sunny day… would you rather be wearing dark coloured or light coloured clothing? It is scientifically proven that dark coloured surfaces absorb significantly more heat compared to light coloured surfaces, so naturally you would be more comfortable wearing light colours out in the sun. Now, when you consider how much direct sunlight your roof gets, you can see how the colour of your roof can make a big difference to the thermal performance of your home.
A darker roof colour is often chosen for its aesthetic value, but dark colours absorb more heat from the sun, making the roof cavity hot and also the rooms below. To keep a dark-roofed home cool on a hot sunny day, you will generally need more insulation and will use more energy (e.g. for air-conditioning) than you would for a home of the same size with a light coloured roof.
A light coloured roof will reflect heat and can help keep your home cooler in the hot weather. You’ll save money on cooling when there is less heat coming in through your roof in the first place, so if you’re looking to maximise the energy efficiency of your home, a light coloured roof is a great start. Combine a light coloured roof with adequate insulation and you will have considerably less heat entering your house from the roof.
If you’re building, there are quite a few light roof colours to choose from. If you already have a dark coloured roof, you may want to consider adding extra insulation to keep your home at a comfortable temperature throughout the hotter months.