This Evidence Review produced by Building Research Establishment (BRE) for the Zero Carbon Hub describes the range of technical and behavioural solutions available to reduce the risk of overheating and measures that can mitigate the potential for overheating in UK homes. These solution include internal and external blinds and shutters.
“Reducing unnecessary heat can be achieved through limiting heat gains, for example, by reducing the amount of:
- Heat from the sun entering the building (solar radiation);
- Internal heat gains such as from the unnecessary use of electrical equipment (and by switching to energy efficient alternatives) or by limiting gains from other sources such as hot water distribution pipes;
- Warmer outside air entering the building.”
The use of internal or external solar shading is an effective way to control solar transmission through glazing. Internal shading intercepts solar radiation preventing it from directly heating internal structures and surfaces in a room and avoiding discomfort and glare of direct sunlight on occupants. However, heat is still convected by the internal shading so warming the room air.
External shading intercepts the short wave solar radiation and prevents it being transferred directly through the window glass to the internal space, being significantly more effective than internal shading.
When blinds are considered as part of a refurbishment the following considerations are relevant:
- Internal blinds are particularly easy to incorporate into a refurbishment and can be retrofitted by an occupant
- External blinds may require planning permission if they are considered as having a significant impact on visual appearance, and may require confirmation of structural suitability for wind and snow loads
- Fixed blinds must offer a good compromise between daylight and solar shading, and must be appropriate for the elevation
- Controllable blinds require maintenance, user adjustment if manually operated and acceptance/understanding of the control strategy if automated
Download the full report here: ZCH-Overheating Evidence Review
For all the resources from the Zero Carbon Hub on overheating in homes see here.