Heatwave: How to Stay Cool Without Breaking the Bank

With temperatures climbing and electricity bills soaring, here is how to get through heatwaves without spending a fortune.

No, you have not tried everything to beat a heatwave. Tired of keeping their shutters closed all day and living in darkness, some people in France are turning to a little-known approach reported by 20 Minutes.

According to our colleagues, the French Ministry of Health advises reducing indoor sources of heat:

“To do this as effectively as possible, the guidance is very clear. During periods of extreme heat, electrical devices that give off heat should be switched off rather than left plugged in. Cutting the power to screens and other boxes via extension leads stops standby equipment from acting like invisible radiators. Modern living can therefore be combined with more minimalist and resourceful habits.”

In any case, France is very hot at the moment, and things are unlikely to improve as summer progresses. If, like us, you are struggling with the heat, you may be tempted to leave your shutters slightly open during the day to create a draught.

As Futura Science explains, that is clearly not a good idea, because shutters play a crucial role during a heatwave:

“This external protection is especially important because, once the sun’s rays pass through windows, they heat the walls, floors and furniture. The heat stored in this way then remains trapped indoors, creating what is known as a domestic greenhouse effect.”

So, when the temperature outside is higher than indoors, you should never leave gaps open during the day.

Natural ventilation: the most effective weapon

Once the temperature has dropped, ventilation remains the ultimate low-cost defence against the heat. The principle could not be simpler: open your windows wide when it is cool, usually overnight, then shut them before temperatures rise again. Creating a through-draught can cool your home without costing a penny.

You then only need to keep that cool air inside during the day by closing every window, shutter and curtain to block the sun’s rays. Yes, your summer may be rather dark, but at least your poorly insulated home will not reach 30°C and you will not spend a fortune on electricity while the air conditioning runs flat out.

You can also use a fan, a formidable ally when used properly. Place it in front of an open window in the evening, where it will draw in the outdoor air as it starts to cool. The experts’ trick? Put a container filled with very cold water in front of the blades.

Evaporation can turn a modest table fan costing just a few euros into a makeshift air conditioner. The cooling effect is felt straight away, and a pedestal fan uses more than 10 times less electricity than a portable air conditioner.

There is also the wet-sheet method used in traditional Maghreb architecture. Damp fabrics are hung in air currents to cool the atmosphere. The modern version involves soaking an old sheet in cold water, lightly wringing it out and hanging it in front of an open window. Evaporation absorbs heat from the incoming air and can reduce the temperature by 4 degrees.

Barricade your home against the sun

If you are in an emergency situation and have very limited means, aluminium foil could come to your rescue. Applied with its shiny side facing outwards on every sun-exposed pane, it turns the windows into reflective mirrors.

This option costs virtually nothing compared with professional solar films, which are sold at a high price. The best approach is still to close your shutters and curtains before the sun returns, after airing your home with cool air throughout the night.

Hunt down hidden sources of heat

As explained above, household electrical appliances can behave like radiators in disguise. A laptop produces as much heat as a 150-watt radiator, while internet routers also give off a constant and unexpected amount of heat. Systematically unplugging all non-essential equipment during heat spikes makes a noticeable difference to the ambient temperature. Do not hesitate to disconnect anything you are not using: the electricity savings will be even greater.

Also watch out for halogen bulbs, which convert electricity into heat. Modern LEDs use ten times less energy and produce negligible heat.

It is not something many people consider, but the kitchen becomes a major issue during a heatwave. An oven can turn any home into a furnace, while hobs emit intense heat. The winning strategy is to prepare meals very early in the morning, when temperatures are still bearable, and favour cold dishes, salads and gazpachos that require no cooking.

Adapt your routine like people in hot countries

For centuries, Mediterranean populations have developed a way of life suited to high temperatures. Their secret? Completely changing their daily rhythm to avoid the hottest hours. Get up at 6 am to enjoy the morning coolness, take a siesta from 2 pm to 4 pm when temperatures peak, then resume activities late in the day as the sun begins to set.

When resting, the human body produces far less heat and uses less energy. The Mediterranean siesta falls exactly during the hours when outdoor temperatures are highest. Of course, this will depend on your work situation, but it is a good way to adapt your routine in summer.

Choose your clothes strategically

Textile materials directly affect how heat feels. Polyester and synthetic fibres trap perspiration, creating a greenhouse effect on the skin. By contrast, linen, cotton and bamboo allow the skin to breathe and encourage natural evaporation.

Colours also have an important physical role. Light shades reflect the sun’s rays, whereas dark colours absorb them and turn them into heat. A black T-shirt in 35°C heat turns the wearer into a walking radiator.

The chilled-laundry technique brings immediate relief. Put sheets, T-shirts and underwear in the fridge for thirty minutes before using them. That instant coolness against the skin temporarily offsets the ambient heat and makes temperature peaks easier to tolerate. Alternatively, there is always Sony’s personal air-conditioning device, although it is not cheap.

Turn your nights into a refuge

Heatwave nights call for minimal, suitable bedding. Duvets and blankets should be replaced with a simple linen or cotton sheet. These natural fabrics wick away body moisture more effectively than synthetic fibres. In extreme cases, sleeping directly on the mattress avoids layering any fabrics at all.

A chilled pillow can work wonders against heat-related insomnia. An hour in the freezer before bed is enough to create a cool spot that lasts for several hours. This method helps you fall asleep despite night-time temperatures above 25°C, and it is not especially expensive.

A hot-water bottle in summer - surely you would have to be mad? In fact, an iced hot-water bottle filled with cold water and placed in the freezer for two hours releases coolness into the bed for hours. Its gradual cooling effect supports falling asleep without causing thermal shock.

Summer means staying hydrated

Hydration in very hot weather follows some counter-intuitive rules. Iced drinks, despite their immediate appeal, hydrate less effectively than lukewarm liquids. They cause thermal shocks that disrupt the body’s temperature regulation. Fresh mint infusions and cucumber-infused water, drunk at room temperature, provide longer-lasting refreshment.

Frequency matters more than quantity. Taking small sips very regularly allows for optimal absorption. The body handles a steady supply of fluid better than a single large intake. This approach keeps hydration stable, even in extreme heat.

Food also actively contributes to cooling the body. Watermelon, cucumber, tomato and courgette contain more than 90% water and perfectly complement liquid hydration. These water-rich foods literally cool you from within while providing the mineral salts lost through perspiration.

Invest wisely without breaking the bank

Some modest pieces of equipment can radically improve thermal comfort. A €35 electric misting fan combines airflow with water evaporation to create a natural air-conditioning effect. Provided you keep it close by, as it cannot cool a large space, it offers immediate relief.

A fan uses 50 watts compared with 2000 watts for a portable air conditioner. Over three months of intensive use, the electricity saving exceeds €200. The tip for remote workers or people stuck in offices where colleagues battle over the temperature: use a desk fan.

This personal fan can keep you cool all day while using very little electricity. You now have all the techniques you need to stay cool at minimal cost.