You can prevent your air conditioner from running all day by ventilating smartly, limiting heat inflow, and setting the thermostat to the right temperature. The combination of good sun shading, night ventilation, and an efficient temperature setting makes all the difference. In this article, we answer the most frequently asked questions about smart cooling in the summer.

How hot does a home without air conditioning get in the summer?

Without air conditioning, the indoor temperature of a home can quickly rise to 30 degrees Celsius or more in the summer, depending on the insulation, location, and type of home. During prolonged heatwaves, such as those occurring increasingly frequently in 2026, the indoor temperature can even become warmer than the outdoor temperature due to heat stored in walls and floors.

Poorly insulated homes and apartments with large glass surfaces are the most vulnerable. Sunlight entering through windows heats the air as well as the furniture and walls, which retain the heat. This heat accumulation means that it can still be very warm in the evening, even when the outside temperature has already dropped. South-facing homes or those with a flat roof heat up particularly quickly.

Which measures reduce heat inflow into the house?

The most effective measures to keep heat out are external sun shading, closing windows and curtains during the day, and limiting heat sources indoors, such as appliances and lighting. Those who tackle the heat at the source need air conditioning much less.

Exterior sun protection, such as screens or roller shutters, keeps up to 70 percent more heat out than interior sun protection. Indoor curtains and blinds also help, but are less effective because the sunlight has already passed through the glass. Furthermore, turn on heat-producing appliances, such as the oven or dryer, late in the evening. Replace incandescent bulbs with LED lighting, as these produce hardly any heat.

Good insulation in walls, roof, and floor plays a major role in the long run. A well-insulated home retains the cool night air longer and heats up more slowly during the day. This is an investment that pays for itself in both summer and winter.

At what temperature do you set the air conditioner most efficiently?

The most efficient setting for an air conditioner in the summer is between 24 and 26 degrees Celsius. Every degree lower means significantly higher energy consumption. A difference of just one degree can increase power consumption by five to ten percent.

Many people set the air conditioning too low in the hope of cooling down quickly. That does not work faster, but it does consume much more energy. Set the air conditioner to a comfortable temperature and let the device do its job. Moreover, a large temperature difference between inside and outside is bad for your body and can cause headaches or cold symptoms.

Use the timer function if it is available. This way, you can have the air conditioner start half an hour before you get home and automatically switch it off when you go to sleep. This prevents unnecessary consumption. If you are still looking for a suitable air conditioner, you can via the air conditioning selection guide Quickly find the right model for your situation.

When is it better to ventilate than to turn on the air conditioning?

It is better to ventilate than to turn on the air conditioning when the outside temperature is lower than the inside temperature, which is typically the case in the summer in the early morning and the evening after sunset. During those hours, natural ventilation is free and effective.

The best strategy is to open windows and doors wide at night and early in the morning to let the cool air in. During the day, close everything again to retain the coolness. This principle is called night ventilation and is one of the most energy-efficient ways to keep a home cool.

On days when the outside temperature rises early and there is hardly any cooling at night, ventilation is less effective. In that case, the air conditioner is the better choice, but use it judiciously: turn it on when really necessary and switch it off as soon as the desired temperature is reached.

How does a good ventilation opening help cool your home?

A good ventilation opening ensures a constant flow of air, allowing heat to be dissipated more quickly and the indoor temperature to drop. Without sufficient ventilation ducts or openings, warm air remains trapped in the home, even if you open the windows.

Draft is the key word: open windows or vents on two opposite sides of the home to create an airflow. Warm air rises, so ventilation openings high in the wall or through skylights are particularly effective. In older homes, these openings are sometimes missing, leading to poor air circulation.

In some cases, it is necessary to have additional ventilation openings made, for example in an exterior wall or foundation for crawl space ventilation. This requires precise drilling in concrete or masonry. Via the pricing tool you can quickly get an indication of what such a job costs.

How much does it cost to run the air conditioning all day?

Running an air conditioner all day costs on average between two and five euros per day, depending on the capacity of the unit, the set temperature, and the current electricity price. Over a full summer, this can add up to hundreds of euros in extra energy costs.

An average split-unit air conditioner consumes between 500 and 1500 watts per hour. At an electricity price of around 30 cents per kilowatt-hour, running it for eight hours quickly amounts to more than a euro per day for an energy-efficient model, and three euros or more for a larger unit. Modern air conditioners with a high COP (coefficient of performance) value are more energy-efficient and cool more effectively.

By only turning on the air conditioning when absolutely necessary, not setting the temperature too low, and properly insulating and ventilating your home, you can significantly limit costs. Smart use makes the difference between a high energy bill and a comfortable, affordable summer.

How De Betonboorder helps with ventilation in your home

A well-ventilated home often starts with the right openings in walls, floors, or foundations. We help you with this through professional drilling, so you are less dependent on your air conditioning. This is what we can do for you:

Drilling ventilation holes in exterior walls for fresh air supply in occupied spaces
Install crawl space ventilation by drilling holes in the foundation, which reduces moisture problems and heating of the ground floor
Implement for ventilation ducts or air conditioning pipes through concrete, stone, or metal
Working in occupied situations, leaving the workplace tidy
Quickly deployableIn many cases, we schedule a professional within two days.

Do you want to know what a ventilation opening or duct costs or is possible in your situation? Contact us and we are happy to think along with you.

This content was generated using AI and may contain errors.

How do you prevent your air conditioning from having to run all day in the summer?