As the UK faces its fourth heatwave of the year, energy experts recommend a simple two-item trick to keep bedrooms cool at night. Specialists at the Local Energy Advice Partnership (LEAP) suggest placing a bowl filled with ice and cold water in front of an electric fan to create a "homemade, DIY air-conditioner." The fan propels air over the icy water, producing a cooling breeze that chills the room without expensive equipment.
Heatwave temperatures and health warnings
Certain areas of southern England could see temperatures between 32°C and 33°C this week. The UK Health Security Agency has issued a warning of possible "significant impacts" on health and social care services, including a rise in deaths among elderly people or those with health conditions, and an increase in drownings. Emergency services are also preparing for further wildfires.
A National Fire Chiefs Council spokesperson said: "With the Met Office warning that a fourth heatwave could develop this week, bringing another period of very hot weather to parts of the UK, fire and rescue services remain on alert and are continuing to prepare for renewed wildfire risk. Most wildfires are preventable and we are asking everyone to play their part in helping to protect our communities, wildlife and natural spaces, while easing the pressure on firefighters who have already faced an exceptionally challenging summer."
Yellow heat alert and staying cool
A yellow heat alert remains active from Tuesday, 9am until Friday, 9am across regions including the East and West Midlands, South-east, South-west, East of England, and Yorkshire and the Humber. Staying comfortable in the UK during a heatwave is difficult, as relatively few properties have air conditioning. Many depend on fans or frozen hot water bottles at night. Most British homes are built to retain heat, which makes sleeping during a heatwave particularly difficult.
LEAP also recommends placing bowls of water on windowsills to cool down, describing the method as "surprisingly effective." Positioning bowls of water throughout the property can assist in cooling warm air, offering a straightforward yet efficient means of reducing indoor temperatures.
How the evaporative cooling trick works
The trick works through evaporative cooling. When a bowl of water is placed in front of a fan or near an open window, the water draws heat from the moving air and gradually evaporates, lowering the temperature of the surrounding air. Adding ice amplifies the effect, as colder water absorbs more heat. LEAP experts say the method is most effective when the bowl is positioned near an open window or directly in front of a fan, as circulating air helps disperse cooler air throughout the home.
Instagram user Samsmith1986, who has more than 2,000 followers, also advocates this trick, describing it as a "simple life hack that can really make a difference." In a video posted during the June heatwave, he explained: "You have to try this if you can't sleep during this heatwave. Grab yourself a bowl of cold water. Place it on the windowsill at night time. Now, the cold water draws in the heat and converts it into vapour. How cool is that?"
The video attracted several comments. One user responded: "Just tried this now and it's defo cooled the room." Another suggested: "Put a bowl of cold water behind an electric fan. As it evaporates, the fan blows the cold vapour at you! It's fabulous!" While this approach can provide some benefit, it typically delivers only limited relief compared to air conditioning. In humid weather or where there is minimal airflow, its efficiency may be considerably reduced.
