Hot weather can make it difficult to fall asleep, cause more nighttime waking and leave you feeling tired the next day. Learning how to keep your bedroom cool can improve sleep quality and make heatwaves more manageable.
The main reason hot weather affects sleep is thermoregulation — the body’s natural process for keeping its internal temperature within a safe range. To fall asleep and remain asleep, the body usually needs to release some heat. A hot bedroom can interfere with this process.
UK summers are also becoming hotter. The Met Office reports that the likelihood of temperatures exceeding 40°C in the UK is now more than 20 times higher than it was in the 1960s. It also estimates a 50% chance of another 40°C day occurring within the next 12 years.
High humidity can make hot nights even more uncomfortable. Research into humidity and heat stress shows that humid conditions increase the strain heat places on the body. Sweating helps cool the body as moisture evaporates from the skin, but evaporation is less effective when the air is already full of moisture.
So, how can you sleep better and stay cool during hot weather?
Air conditioning can provide effective relief, but it may be too expensive or impractical for many households. According to the Energy Saving Trust, the electricity unit rate under the July to September 2026 price cap is 26.11p per kWh for direct debit customers. A small portable air-conditioning unit using approximately 1kW for seven hours each night over 30 nights would cost about £54.83 in electricity alone, excluding the cost of the unit.
Research into overheating in homes highlights the value of shading and ventilation as passive cooling measures. These methods can reduce indoor temperatures without relying on mechanical cooling. Before trying to cool the air, it is useful to limit the heat entering your home. Most indoor heat comes from sunlight through windows, known as solar gain, and warm outdoor air.
These eight practical tips can help keep your bedroom cooler before bedtime and improve sleep during hot weather.
1. Block sunlight during the day
Keep curtains, blinds or shutters closed on sun-facing windows during bright, sunny periods. This helps prevent sunlight from heating floors, walls and furniture. External shading, including awnings, shutters and outdoor blinds, can be even more effective because it blocks sunlight before it reaches the window glass.
Opening windows is not always the best way to cool a room. If the air outside is hotter than the air indoors, open windows can increase the temperature inside your home. Open them when outdoor air is cooler, such as early in the morning, in the evening or overnight. Close them during the hottest part of the day if outside temperatures are higher.
2. Use cross-ventilation when outdoor air is cooler
Cross-ventilation involves opening windows or doors on different sides of a home to create a flow of air. When the air outside is cooler, this can remove heat that has accumulated indoors. Research into passive cooling in homes suggests that night-time ventilation can reduce overheating, although results depend on the building, outdoor temperature, noise, safety and air quality.
3. Cool conservatories and sun-facing rooms
Conservatories can become extremely hot because sunlight passes through the glass and warms the surfaces inside. Ventilate the space where possible and close internal doors between the conservatory and the rest of the house. Blinds, shutters, awnings, reflective window film and shaded roofing can all help reduce solar heat gain.
Lofts and top-floor rooms may also become uncomfortably warm because roofs absorb solar heat. Loft ventilation and reflective roofing materials may help in some properties, although these options usually require a larger investment. Solar panels can generate electricity while also providing a layer between the roof and the building, potentially reducing heat transfer.
4. Sleep in the coolest room available
Bedrooms on upper floors or rooms facing south or west are often among the hottest areas of a home. Heat rises through the building, while sun-facing walls and roofs can continue releasing stored heat after sunset.
During a heatwave, consider sleeping on the ground floor or in a room on the north-facing side of the property if it is safe and practical to do so.
5. Limit indoor heat and humidity
Ovens, hobs, tumble dryers, washing machines and dishwashers can all increase indoor temperatures. Cooking and drying clothes indoors can also raise humidity, making it more difficult for sweat to evaporate.
On particularly hot days, use heat-producing appliances earlier in the morning or later in the evening. Run extractor fans while cooking or showering to remove warm, moist air before it spreads throughout the home. Research into moisture movement and extractor fans indicates that ventilation can reduce the spread of moisture from kitchens and bathrooms into other rooms.
6. Choose lightweight, breathable bedding
A review of sleepwear and bedding fibre types found that clothing and bedding materials can influence thermal comfort during sleep. Lightweight, loose-fitting sleepwear and breathable bedding may help the body release heat. Cotton and linen are popular choices because they absorb moisture and allow air to circulate, although the fabric’s weave, thickness and moisture-management properties also affect comfort.
During hot weather, avoid heavy duvets, thick blankets and tight synthetic fabrics that may trap heat and moisture close to the skin.
7. Use bedroom fans safely
Evidence on electric fan use in hot weather suggests that fans can provide relief in many conditions, but their safety and effectiveness depend on factors including temperature, humidity, hydration, age and overall health.
Fans do not lower the air temperature. Instead, they move air across the skin, which can improve sweat evaporation and make you feel cooler.
During periods of extreme heat, fans may not provide enough protection, particularly for older adults and people who are dehydrated or unwell. If you use a fan, drink enough water, avoid directing it continuously at your face while sleeping and stop using it if you feel hotter, dizzy or unwell.
8. Try affordable cooling aids
Reusable ice packs, freezer blocks and cooling pillows may help some people feel more comfortable at night. Always wrap ice packs in a cloth or place them on a tray to prevent condensation from soaking your bedding and to avoid direct contact between very cold surfaces and your skin.
Cooling mattress toppers and bedding made with water-based systems or phase change materials may also help regulate temperature. These materials absorb, store and release heat as they change state, although their price and effectiveness vary.
Better sleep during hot weather starts well before bedtime.
The most effective strategy is usually a combination of measures: block direct sunlight during the day, ventilate when outdoor air is cooler, reduce heat from household appliances, sleep in the coolest room available and choose bedding that allows heat and moisture to escape.
Source: www.sciencedaily.com