9 tips for a cool car: What helps best when it's hot in the car?

Heat in a car is more than just annoying – it impairs concentration, reaction time, and circulation. The ADAC estimates the risk of an accident to increase by up to two percent for every degree of interior temperature above 25°C. Children, the elderly, and animals are particularly vulnerable because their bodies are less able to dissipate heat. Heatstroke can occur at interior temperatures of around 41°C.

If you deliberately park your vehicle in the shade, you can keep the interior several degrees cooler even before you set off. Parking garages or parking spaces under photovoltaic roofs are ideal. If only one tree is available, it's worth checking the position of the sun: A west-facing car will receive full sun on its windshield in the afternoon, while a north- or east-facing cockpit will remain noticeably cooler.

2. Half garage or reflective windscreen cover

A tight-fitting half-garage made of aluminum-coated fabric reflects up to 80 percent of the radiation. ADAC measurements show that after four hours of midday sun, the interior was up to ten degrees cooler than the reference vehicle. Those who only protect the windshield should choose an external, reflective mat – it blocks the heat before it can heat up the dashboard.

3. Door swing trick before driving off

Before the engine starts, the driver's door is fully opened. Then, the passenger door is vigorously swung open and closed five or six times. This pumping motion forces the trapped hot air out of the interior in seconds and replaces it with cooler outside air. This process noticeably lowers the perceived temperature and reduces the load on the air conditioning system.

4. Use air conditioning efficiently

After the door trick, all windows should be left slightly open for two minutes while the ventilation system runs at full speed. Then the windows are closed and the recirculation function is activated. This ensures that the system primarily reconditions the already pre-cooled indoor air. A target temperature of 22 to 24°C is considered ideal; the difference to the outside temperature should be a maximum of six degrees to avoid circulatory problems.

5. Cover the steering wheel and seats

Dark surfaces can heat up to over 70°C in the sun. A light-colored cotton cloth or a special cover lowers the surface temperature by up to 30°C. Owners of leather seats benefit twice: The cover also protects the material from fading and cracking.

6. Maintain ventilation system regularly

A fresh cabin air filter and a clean evaporator are the foundation for efficient cooling. Workshops recommend replacing the filter at least once a year or every 15,000 kilometers. If airflow is restricted or there is a musty smell, cleaning the evaporator can help.

Small children and pets should never be left unattended in a car in hot weather – this can be life-threatening after just a few minutes. Anyone who discovers a helpless person in an overheated car should call emergency services immediately and, in an emergency, may even break the window to save lives. According to Section 323c of the German Criminal Code (StGB), first aid is mandatory – anyone who fails to help is committing a criminal offense, and there is no legal penalty for the damaged window in such cases. Important: If possible, document the situation, for example, using a smartphone.

7. Retrofit seat fans or ventilation mats

Universal ventilation pads with small fans cost from around €40 and plug into a 12-volt outlet. They direct fresh air over the back and thighs, allowing sweat to evaporate more quickly. Frequent riders, in particular, notice the significant increase in comfort in midsummer.

8. Drink enough and use a cooler

Even a fluid deficit of two percent of body weight noticeably reduces reaction time. A small thermoelectric cooler keeps water and isotonic drinks up to 18°C ​​below ambient temperature—ideal for long stretches.

9. Plan regular breaks

A break should be taken at least every two hours. Park the car in the shade or in a ventilated area, open all doors, and take a short break. These breaks stabilize body temperature and permanently increase concentration.

Some protective measures against heat in cars sound promising, but in practice have little effect. One example is choosing white paint . While the exterior surface remains significantly cooler—in an ADAC test, the paint temperature of a white car was 44°C compared to 65°C for a black one—the difference in the interior was only five degrees. The effect of interior-mounted sun protection films is similarly disappointing: They barely reduce the temperature in the interior. Reflective mats mounted on the exterior are considerably more effective.

Even tinted windows only contribute minimally to cooling the interior—a difference of around two degrees was measured. Nevertheless, they can be useful, especially for protecting the rear seat: Here, the seat surface heated up to only 48°C, not 57°C, compared to the unprotected vehicle. This can be crucial for children or animals in the back seat. However, this effect is no substitute for comprehensive heat protection.

How long does it take for it to get really hot inside a car? After just ten minutes, it can be ten degrees hotter inside than outside. After 30 minutes, temperatures often reach 50°C – even in moderate temperatures.

What's the best way to quickly cool down a hot car? Open the windows briefly, then swing the doors open and close. Then close the windows, turn on the air conditioning, and activate the recirculation. This is the fastest way to cool down the interior air.

Does it help to leave the window slightly open when parking? Only to a limited extent. The temperature difference is usually a maximum of one or two degrees. This hardly helps against the sun's rays – sun visors or a semi-garage are better.

How harmful is it for my car if it's often left in the sun? UV radiation attacks seals, plastic, and leather. Colors fade, and the dashboard can crack. Simply using a sunshade or parking in the shade can significantly slow this process.

Can I leave my pet in the car for a short time in hot weather if the window is open? No. Even with the window open, the car can become dangerously hot within minutes. Pets should never be left alone in a car.

What's the best way to protect children from the heat in the car? Child seats should be covered with cloths. When setting off, cool the car down first, then let the children get in. Rest breaks in the shade are mandatory.

Which tools are really worthwhile for the summer? Reflective covers for windshields and side windows, a semi-garage, ventilation pads, and a cooler are particularly effective. Interior film or white paint alone are less useful.