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To keep a home cool, it is important to first understand where the heat comes from. The main source is often direct sunlight. Through windows, the sun’s rays heat up indoor surfaces and create a greenhouse effect that traps the heat.

Outdoor heat also gradually enters through walls, windows and the roof. Attic apartments are particularly exposed, as their roof absorbs sunlight throughout the entire day.

Finally, electrical appliances, cooking, lighting and high humidity levels can further increase the temperature.

Adapting your habits to hot days

During periods of intense heat, the goal is to prevent heat from entering. Close blinds, shutters or curtains before the sun directly reaches your windows.

Also reduce sources of heat inside your home: turn off unused devices and avoid using the oven or stovetop during the hottest hours of the day.

Ventilating effectively

When the outdoor temperature is higher than the temperature inside your home, keep the windows closed. In summer, it is better to ventilate early in the morning or late in the evening, when the outside air is cooler.

For maximum efficiency, create airflow by opening several opposite windows for about 30 minutes. Also remember to open the doors of rooms and cupboards to release accumulated heat.

Taking advantage of evaporative cooling

The evaporation of water absorbs some of the heat present in the air. For example, you can hang a damp sheet in front of an open window during the cooler hours or dry damp laundry inside the room. However, this solution should be used in moderation to avoid excessive humidity.

Installing external sun protection

External sun protection remains the most effective solution against heat, as it blocks the sun’s rays before they reach the windows.

Roller shutters, shutters and external blinds provide the best protection by significantly limiting solar radiation. For balconies and terraces, awnings, shade sails or parasols can also help reduce sun exposure.

Using internal sun protection

If an external installation is not possible, especially in rental properties, some solutions can still help reduce heat.

Roller blinds, thermal curtains or pleated blinds with a reflective surface reduce part of the incoming solar radiation. Solar protection films applied directly to windows can also filter part of the infrared radiation, although they may sometimes reduce natural light.

Adapting your interior during summer

A few simple adjustments can improve the feeling of freshness in your home:

  • Remove thick carpets: they retain heat and prevent the floor from cooling down effectively. Comfortable in winter, they are less suitable during periods of intense heat.
  • Choose light colours: white walls and bright surfaces reflect more sunlight and absorb less heat.
  • Add plants: thanks to the evaporation of water through their leaves, they help slightly cool the air while improving indoor comfort.

Sleeping close to the floor

As warm air naturally rises, areas closer to the floor often remain slightly cooler. During very hot nights, sleeping closer to the floor can therefore improve comfort.

Also close the doors of unused rooms during the day to limit the spread of heat and preserve the areas you want to keep cool.

Closing the doors of unused rooms

Although creating airflow is ideal when ventilating, it is better to keep the doors of unused rooms closed during the hottest hours. This helps limit the circulation of warm air and preserve freshness in essential areas such as the living room or bedroom.

A few additional tips

Take a lukewarm shower before going to sleep: unlike a cold shower, it prevents the body from reacting by producing additional heat.

  • Cool your pillow: placing your pillowcase in the refrigerator for a few minutes can provide a refreshing feeling when going to bed.
  • Use LED bulbs: they produce much less heat than older incandescent bulbs, which convert a large part of their energy into heat.
  • Use a fan or air conditioner in moderation: these devices can improve comfort by creating airflow or lowering the temperature, but they should be used efficiently to limit energy consumption.

Common mistakes to avoid

  • Leaving windows open all day: when the outside air is warmer than indoors, this allows heat to enter and gradually increases the temperature of your home.
  • Leaving a fan running in an empty room: a fan does not actually cool the air; it only creates a feeling of freshness through the movement of air on the skin.
  • Creating too much humidity: damp sheets and other evaporation methods should be used in moderation. Excess humidity can make heat harder to tolerate and encourage the development of mould.

Sources 

landi.ch - Article 

hoval.ch - Article 

watson.ch - Article