You keep your house cool during a heatwave by keeping the sun out, only ventilating when it is cooler outside than inside, and keeping the air moving with a fan. During the day, keep windows and curtains on the sunny side closed; in the evening and at night, open windows for cross-ventilation. Following this routine keeps an average home noticeably more comfortable.
Quick answer: close blinds and curtains during the day, only ventilate when it is cooler outside than inside, turn off appliances that emit heat, and use a fan or air cooler to make the heat more bearable. This won't lower the indoor temperature to air-conditioned levels, but it will prevent the house from heating up further.
Keep the sun out: blinds first
Most heat enters through the glass. External shading works best because solar radiation is blocked before it reaches the window. If you don't have that, light-colored, opaque curtains, roller blinds, or window film will help significantly. Close them early in the morning on the sunny side and only open them once the sun has moved away from the window. Once a room has heated up, it is very difficult to cool it down again in the evening.
Ventilate at the right time
Opening windows when it is hot outside means letting heat in. Therefore, ventilate early in the morning, late in the evening, and at night. Open two windows or doors on opposite sides to create a cross-breeze, which will help the house cool down faster. Close everything as soon as the outside temperature exceeds the inside temperature.
Limit heat from your own household
Ovens, stoves, tumble dryers, and even old light bulbs emit heat. On hot days, try to eat cold meals or cook outside, do laundry and drying in the evening, and turn off devices that are in standby mode. Every heat source you turn off saves your fan some work.
How to use a fan or air cooler to help keep the house cool
A fan does not lower the room temperature, but the airflow evaporates sweat from your skin, making you feel cooler. That is exactly what a heatwave is about: helping your body cool down. So, place the fan where you are sitting or sleeping and use a curtain or window for extra airflow. Read where to best place it in Where do you place a fan for the best cooling?. In extreme heat, you can read in Does a fan help when it's 35 degrees? when a fan actually has less effect.
An air cooler can provide an extra fresh breeze in a personal space, provided you ventilate occasionally so that humidity does not rise too much. If you suffer from warm nights, our article How do you sleep well when it's warm in the bedroom? will help.
Overview: what does each measure achieve?
The table provides a general estimate. The effects vary depending on the home, its orientation, and the weather.
| Measure | What it does | When |
|---|---|---|
| Close blinds and curtains | Keeps solar heat out | Daytime on the sunny side |
| Cross-ventilation | Removes warm air | Evening, night, and early morning |
| Fan | Makes the heat more bearable | Where you are sitting or sleeping |
| Air cooler | Extra fresh breeze via evaporation | In a small room, with occasional ventilation |
| Turn off heat sources | Prevents additional heating | All day |
Dynter products for warm days
The Dynter AV25G is a pedestal fan, fully collapsible and adjustable in height from 80 to 125 cm.
Airflow: 5.3 m/s and a CADR value of 3533 m³/h according to the product page
Control: dial with three speed settings and an oscillation function
Power: 55W (AC motor)
Folded size: 42 x 42 x 20 cm, weight 3.49 kg
Are you looking for a slim option with a remote control? The tower fan TV26G is 115 cm tall, has a timer function up to 7.5 hours, and a Sleep mode for the night. The SM211 air cooler is also a compact solution for your workspace or bedroom.
View the Fan AV25G White, the Tower Fan TV26G, or the entire collection of air conditioners and fans.
Please note: in high temperatures, vulnerable people, such as young children, the elderly, and those with health conditions, can be affected by the heat more quickly. A fan is not a medical measure. If you are in doubt or feel unwell, please contact your GP.
Frequently Asked Questions
How many degrees cooler does it get with a fan?
A fan does not lower the room temperature, but it makes you feel cooler because sweat evaporates faster.
Should you keep windows closed or open during a heatwave?
Closed during the day if it's warmer outside than inside; open in the evening and at night if it's cooler outside.
Does sun shading really help?
Yes, sun shading keeps solar heat out before it enters through the glass. External shading is the most effective.
Is an air cooler better than a fan?
An air cooler provides a fresher breeze but adds moisture to the air. For large rooms, a fan is often more practical.
Can I leave a fan running all night?
Usually, you can, but read our tips in Can a fan be left on all night?.