How to keep your home cool in summer in the UK

Quick answer

To keep your home cool in summer, open windows early in the morning and later in the evening when the air outside is cooler. During the hottest part of the day, close windows, blinds and curtains to stop warm air and direct sunlight getting in.

Focus first on south and west-facing rooms, bedrooms, conservatories and rooms with large glazed doors. Use fans to move cooler air through the home, avoid heat-producing appliances during the hottest hours, and check whether old or poorly sealed windows are making rooms harder to control.

Introduction

After weeks of rain and unpredictable weather, a sudden heatwave can catch many people off guard. Before long, rooms start to feel stuffy, temperatures climb indoors, and keeping your home comfortable becomes a daily challenge.

Most UK homes weren’t designed with hot summers in mind. They were designed to hold onto heat, block draughts and make winter easier to live with. While this is useful in January, it can become a problem when temperatures soar in the warmer months.

The good news is that there are several practical ways to reduce heat build-up and keep your home cooler during warmer weather. A cooler home is usually the result of small, sensible changes: blocking direct sun, using your windows at the right time, reducing indoor heat, improving ventilation and choosing glazing that performs better all year round.

In this guide, we’ll explain why UK homes can feel particularly uncomfortable in summer, practical ways to make your home cooler, and how energy-efficient windows can help keep your home more comfortable.

Why UK homes get so hot in summer

UK homes often overheat because they trap heat well but don’t always release it easily.

The main causes are:

• Solar gain: Sunlight passes through windows and warms floors, furniture and walls.
• Poor ventilation: Warm air gets trapped, especially upstairs.
• South and west-facing windows: These rooms often receive the strongest sun.
• Large areas of glass: Conservatories, patio doors and garden rooms can heat up quickly.
• Indoor heat: Cooking, tumble dryers, electronics and lighting all add warmth.
• Older windows: Poor seals, stiff openings or failed glazing can make temperature control harder.
• City location: Homes in cities such as Bristol can be at greater risk during heatwaves because built-up areas tend to retain more heat.

The goal is simple: keep direct sun out, let cooler air in at the right times, and avoid creating unnecessary heat indoors.

1. Should you open your windows in summer?

The first thing most homeowners do when their home is too hot is open the window. However, this could actually be making your home warmer. A simple rule of thumb is to open your windows when it’s cooler outside than inside, and keep them closed when the outside air is warmer.

Opening a window in the middle of a hot afternoon pulls hot air into the room, undoing the benefit of keeping blinds or curtains closed and potentially warming the home further.

Use this approach instead.

Open windows early in the morning (7am – 9am)

Morning air is usually cooler, so open windows before the day heats up.

Open windows on opposite sides of the house where possible. This creates cross-ventilation and helps move stale, warm air out.

Fred the Oyster, CC BY-SA 4.0, via Wikimedia Commons

Close windows during the hottest part of the day (9am – 9pm)

When it’s hotter outside than inside, close your windows.

This slows warm air from entering the home. It works best when you also close blinds, curtains or shutters on sunny windows.

Open windows again in the evening (from 9pm onwards)

Open windows again once the outside temperature drops.

This helps release heat that has built up during the day, especially upstairs. Keep internal doors open where practical so air can move through the home.

Use trickle vents for background airflow

Trickle vents can help maintain light ventilation when you don’t want windows fully open.

They won’t cool a hot room quickly, but they can reduce stuffiness and support airflow.

2. Block sunlight before it heats the room

Stopping direct sunlight from entering your home is another simple way to reduce your home’s heat. 

Close blinds, curtains or shutters on sun-facing windows before the room gets hot. Do this in the morning for east-facing rooms, during the day for south-facing rooms, and in the afternoon for west-facing rooms.

This is especially important because once sunlight heats your flooring, furniture and walls, the room will keep releasing heat for hours.

For larger glazed areas, such as patio doors, bi-fold doors and conservatories, shading is even more important. Thermal blinds, shutters, awnings, pergolas and roof blinds can all help reduce heat build-up.

If you are planning new doors, think about sunlight as well as style. Large panes of glass can look fantastic, but they need the right glazing, ventilation and shading to stay comfortable in summer.

3. Reduce heat inside the home

Cut down on anything that adds heat indoors.

Practical changes include:

• Cook earlier in the day or use smaller appliances instead of the oven.
• Avoid tumble drying during hot weather.
• Turn off unused electronics.
• Switch to LED bulbs if you still have older lighting.
• Keep bathroom and kitchen extractor fans running after showers or cooking.
• Dry clothes outside where possible.

Although these changes are small individually, they add up during a warm week.

4. Improve airflow through the house

Moving air makes a warm home feel more comfortable.

Use fans near open windows in the morning or evening to help draw cooler air through the home. If you can, open windows on opposite sides of the property to create a natural cross-breeze

Upstairs rooms often need extra attention because warm air rises. Open landing and bedroom windows in the evening to help heat escape before bedtime.

Window style can also make a difference. Windows that open easily, safely and widely give you more control over ventilation. If your windows are stiff, painted shut or awkward to use, you are less likely to ventilate properly when you need to.

5. Focus on the hottest rooms first

You don’t need to cool the whole house at once. Start with the rooms that cause the most discomfort:

• Bedrooms
• South-facing living rooms
• West-facing bedrooms
• Conservatories
• Loft conversions
• Rooms with large glazed doors
• Home offices

For bedrooms, focus on blocking afternoon sun and ventilating in the evening.

For conservatories, prioritise roof shading, blinds and ventilation. Older conservatories with polycarbonate roofs often overheat because the roof lets in too much heat during summer and loses too much warmth in winter. Upgrading your conservatory with a tiled roof can help maintain a more comfortable temperature, while also improving the look of your home and boosting kerb appeal. 

For home offices, reduce appliance heat where possible. Computers, monitors and chargers can make a small room feel much warmer by the end of the day.

6. Check whether your windows are making the problem worse

Your windows affect how easily heat enters, escapes and moves through your home.

Older or poorly performing windows can make summer comfort harder to manage. Common signs include:

• Draughts around the frame
• Failed or misted double glazing
• Stiff openings
• Damaged seals
• Rooms that are too hot in summer and too cold in winter
• Condensation problems in colder months

Modern energy-efficient windows are designed to slow heat transfer. In winter, this helps keep warmth inside. In summer, it can help reduce unwanted heat gain when paired with shading and sensible ventilation.

While windows will not solve overheating on their own, they are an important part of a cooler, more comfortable home.

How energy-efficient windows help in summer and winter

Energy-efficient windows help keep indoor temperatures more stable.

In winter, they reduce heat loss. This helps rooms feel warmer, cuts draughts and can reduce wasted energy.

In summer, they slow heat transfer through the glass and frames. This makes it easier to keep rooms comfortable.

Good replacement windows can also improve:

• Ventilation control
• Security when airing rooms
• Draught reduction
• Noise reduction
• Year-round comfort
• Kerb appeal

At CR Windows, we manufacture and install energy-efficient windows for homes across Bristol and the South West. We can help you choose window styles, frame materials and glazing options that suit your property and how each room is used.

If your current windows are draughty, misted, awkward to open or poor at regulating temperature, upgrading could make your home more comfortable in both summer and winter. Get in touch to learn more. 

Quick checklist: how to keep your home cool in summer

Use this simple summer routine.

• Open windows early in the morning.
• Close windows when it becomes hotter outside than inside.
• Close blinds or curtains before direct sun hits the glass.
• Focus first on south and west-facing rooms.
• Open windows again in the evening.
• Use fans to move cooler air through the home.
• Avoid cooking, tumble drying and running heat-producing appliances during the hottest hours.
• Keep internal doors open when you want airflow.
• Ventilate upstairs rooms before bedtime.
• Check whether old windows are making rooms harder to manage.

FAQs

Is it better to keep windows open or closed in hot weather?

Keep windows open when it’s cooler outside than inside. Keep them closed during the hottest part of the day if the outside air is warmer.

Do curtains and blinds keep a house cooler?

Yes. Curtains and blinds reduce direct sunlight entering the room. They work best when closed before the room heats up.

Why is my bedroom so hot at night?

Bedrooms often stay hot because warm air rises and because walls, floors and furniture release stored heat from the day. West-facing bedrooms can be especially warm in the evening.

Can double glazing keep a house cooler in summer?

Double glazing can help slow heat transfer, which makes indoor temperatures easier to manage. It works best alongside shading and good ventilation habits.

Should I replace my windows to keep my home cooler?

If your windows are old, draughty, misted or hard to open, replacing them may help. But for the best results, combine better windows with shading and sensible ventilation.

Final thoughts

Keeping your home cool in summer is about control.

Block sunlight before it heats the room. Open windows when the air outside is cooler. Close them when the air outside is hotter. Reduce indoor heat from appliances. Use fans and ventilation to move warm air out.

And if your windows are draughty, misted or difficult to use, they may be making your home harder to keep comfortable.

Energy-efficient windows can help create a home that feels better in summer and winter. For advice on replacement windows in Bristol and the South West, contact the CR Windows team today.