Overheating – why it occurs and how to tackle it

As temperatures begin to increase in the UK climate, overheating risk is becoming more common across our housing stock. But why does this happen?

It could be thought that high levels of insulation would increase the risk of overheating. However, recent studies demonstrate that higher levels of insulation, particularly in lofts and roof spaces, can actually reduce overheating instead — therefore, poor insulation can actively contribute to the risk of overheating in your home.

The fundamental cause of overheating is ‘solar gains’, where the building is being heated up by the sun. This occurs predominantly through glazing, if it is poorly placed around the building, over-sized and unshaded, and if there is poor ventilation throughout the property to replace the air being heated inside.
Therefore, key things to consider how to reduce overheating through solar gains are:

  • Insulation – ensure you have sufficient insulation across your home. If you have an uninsulated sloping roof, this can allow a lot of solar gain to occur.
  • Window placement – this is of course hard to change in an existing building, but in new-builds it is crucial that an environmental strategy is considered when planning the placement of windows (your architect will be able to advise on this).
  • Shading – are the windows shaded? This could be through surroundings such as other buildings, trees etc. or window shading can be installed on your window openings. External shading, such as roof overhangs and shuttering, will be more effective than internal shading, such as blinds. Please note, blinds can also negatively impact airflow for ventilation.
  • Ventilation – do you have adequate ventilation throughout the home? This could be through trickle vents combined with operable windows, or even mechanical ventilation systems. Single aspect properties (buildings that have all windows/openings on one side of the property) will often find it harder to achieve cross ventilation, so other ventilation strategies may need to be considered.

To help you identify the level of risk your property has for overheating and explore some possible solutions, a helpful tool has been created by the Good Homes Alliance which you can access below:

To delve deeper into understanding how to prevent overheating in your home, and different approaches you can take, check out the recording from our webinar Summer comfort — keeping cool at home in a warming climate with Sustainability Consultant, Julie Godefroy.