How to Keep Cool in Summer in an Older Home
If you live in an older building and are looking for ways to keep cool in the summer months, this page summarises what you can do. We have listed options in order of priority, considering their benefits, costs and technical risks.
Older buildings were often designed with thick solid walls and natural ventilation. Later the walls became slimmer, the ceilings higher and windows larger. With a few simple adjustments, older homes can be more comfortable through hotter summers while still protecting the character that makes them special.
How comfortable you feel in your home can be impacted by the amount of airflow, levels of humidity and how exposed you are to the sun. The internal temperature will impact whether your home feels comfortable or not.
The temperature inside your home can increase through:
- Internal heat gains: excess heat from lighting, equipment, cooking and people
- External heat gains: from the sun shining on or into your home (solar gain), to high external air temperatures entering via open windows
Priority 1: for everyone in every home
These are easy-to-install measures with a quick pay back.
Tenants can take up most of these actions too but check your lease and talk to your landlord first.
Shutters, curtains and blinds not only provide privacy, security and weather protection, they also protect against heat gain and overheating:
- Internal shutters, thick blinds and curtains are not as effective as external options but can still provide some heat reduction.
- Solar control film on windows is another alternative and can reduce heat gain from sunshine. Simple measures that do not require fixing or permissions to reduce solar gain might be using a sheet to cover the outside of glazed areas.
At night, once the external temperature has dropped below the temperature inside the building, opening windows can release hot air that has built up during the day and let cooler air flow through the space.
To increase the cooling effect, ensure that curtains (or other window coverings) are not blocking the flow of air. Using a fan in front of the window can also help to remove hot air by blowing the air out and drawing in cooler air.
During the day, if the external temperature is higher than that inside the building, opening windows may cause internal temperatures to rise. While sunlight is shining on or into your home, use shutters, curtains or blinds to shade your home from solar gains.
In summer, removing rugs from suspended timber floors that have not been insulated provides cooling benefits from draughts rising through the gaps in floorboards.
Increasing loft insulation can help reduce overheating to the upper floors by stopping sun that heats the roof from entering the building. It is important to make sure loft ventilation is still adequate.
Insulating exposed domestic hot water pipework, hot water cylinders and storage tanks, stops them contributing to the internal heat gains.
Replace any remaining fluorescent or halogen lights with more energy efficient LED lights, that do not produce excess heat.
Where possible, consider reducing internal heat gains from equipment as well as lighting, and from activities such as cooking.
Priority 2: suitable for some homes
These changes can work well to reduce solar gain and overheating but they are a little more complicated and can cost more.
In some circumstances, you will want to hire a specialist to manage the introduction of these measures.
In some cases, these changes will need expert planning, design, and integration with your home if they are not to cause unintended damage or cost more than they will save. They are also likely to require permissions, such as listed building consent, planning permission or building regulation approval.
Installing external shutters, awnings and blinds is the most effective way of reducing solar gains and preventing overheating in the summer.
These features along with others were used by our ancestors to cool their buildings. Even where the existing building no longer has them, there may be evidence that they were fixed to your building in the past, or appropriate historical examples in the surrounding area.
Select exterior surface finishes with a high reflectivity (light coloured paints) or introduce window films, or light coloured paving. Reflective coatings can reduce the warming effect of the sun by reflecting some of it back instead of absorbing the full amount. These can be simple measures such as lime washing walls in white or another light colour.
Many homes were constructed so that the windows at the front and back of the house were directly opposite the internal doors and one another. This allowed some air to flow across the full depth of the house when the windows were open. Ensuring these routes aren't blocked when altering your home improves ventilation.
Another typical detail in older homes are sash windows. Sash windows provide an effective way to naturally ventilate a room. By sliding both the top and bottom panels open, they create a continuous, cost-free convection cycle where warm, stale indoor air rises and escapes through the top gap, while denser, cooler outdoor air is drawn in from the bottom. Both top and bottom sashes can be opened simultaneously or separately, with restrictors for safety and security.
In addition, common features such as windows on top floors/landings, trickle vents, ventilation grilles and chimneys provide natural ventilation. These all allow hot air to rise and escape, drawing cooler air in from the lower floors.
Mechanical ventilation can provide some air movement to improve comfort in hot weather. This could be by fans with a plug, or they could be wired directly into the house's mains electrics.
This will involve the installation an air conditioning unit, and sometimes associated ducting. It is an energy intensive process that will result in higher electricity bills in the summer.
Where possible, favour natural planting over hard landscaping. The presence of vegetation and water can provide cooling effects to their surroundings, for example green roofs, gardens, parks, ponds, etc. Other benefits may include improved biodiversity and reducing surface water flooding.
Tip: Hot weather may become more common as the climate changes. Energy efficiency measures that do not include ways to ventilate or cool your building may cause overheating and poor indoor air quality. For example:
- Introducing new double glazed windows or secondary glazing can reduce ventilation. This can cause overheating in summer and/or high humidity levels, which may affect the health and wellbeing of the occupants.
- Internal wall insulation used on thick stone or cob walls can separate the internal environment from the wall's natural ability to buffer temperature and humidity.
Retrofit measures should always aim to reduce the risk of overheating. For example, by adding external shading where appropriate. Or by identifying safe and secure ways to open upper windows and roof lights at night to expel the warm air, and draw in cool air via lower windows.
Get the help and permissions you need
Before you take advice from any specialist or hire a contractor, let them know that you want to use the 'whole building approach' to plan and implement your changes. Ask if they have experience of using it and for previous examples of their work.
Check what permissions you may need
Before starting installation works make sure you have all the necessary permissions and approvals.
Find guidance on complying with building regulations
The work may need to be checked by a building control body or self-certified by a contractor approved under the 'competent person' scheme.
When the work is finished
When the contractor or installer finishes the work, check that you understand what has been done. Find out how it is supposed to work, how to use any controls and how it should be maintained.
You can use your energy bills to compare levels of energy use before and after improvements to get an idea of the impact and savings achieved.
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