A home with many windows quickly becomes a greenhouse as soon as the sun shines directly on it. An air conditioner certainly helps, but only if you use it smartly in combination with the right sun protection and proper placement. Without that combination, your air conditioner will work overtime and you will never reach the desired temperature. In this article, we answer the most frequently asked questions about using air conditioning in a glass home.

Why do homes with many windows heat up so quickly?

Homes with many windows heat up quickly because glass lets sunlight through but traps the heat released afterwards. This effect, also known as the greenhouse effect, causes the indoor temperature to rise much faster than the outdoor temperature. Especially on south-facing facades with large windows, the indoor temperature can rise to well above 30 degrees in the summer.

Glass has a low insulation value compared to a wall. Even modern double glazing allows a significant amount of solar energy to pass through. That energy is converted into heat as soon as it falls on floors, furniture, and walls. The material stores the heat and releases it slowly, even hours after the sun has set. This explains why glass homes remain warm for a long time, even in the evening.

The larger the glass surface area and the more direct the sun orientation, the stronger this effect. A home with floor-to-ceiling windows facing south or west experiences this most intensely. In 2026, we will see an increasing number of homes with large windows due to architectural trends, making this problem more relevant than ever.

Does an air conditioner really help when the sun shines directly on your windows?

Yes, an air conditioner also helps with direct sunlight, but its effectiveness depends heavily on the situation. If the sun shines through your windows unimpeded, the air conditioner has to constantly fight against a continuous influx of heat. The device can cool the room, but it consumes significantly more energy to do so and reaches the desired result more slowly.

An air conditioner works by extracting heat from the indoor air and discharging that heat to the outside. This process is effective as long as heat production in the room remains manageable. With direct sunlight on large window surfaces, the heat input is so high that even a powerful air conditioner struggles to keep up.

The solution is not to purchase a larger air conditioner, but to limit the heat input itself. External window shading reduces the heat entering the room in the first place, allowing the air conditioner to perform its job optimally. Do you want to know which air conditioner suits your situation? Via the air conditioning selection guide You will quickly find the right model for your home.

Which sun protection works best in combination with air conditioning?

Exterior sun shading is by far the most effective choice in combination with air conditioning. Screens, awnings, or drop-arm screens on the outside of the window keep the sun's heat out before it can penetrate the glass. Interior sun shading, such as curtains or roller blinds, lets the heat in and therefore has a much smaller effect on the indoor temperature.

Exterior sun protection: screens and awnings

Screens are specially designed to block sunlight without completely obscuring the view. They can block up to 90 percent of solar energy, depending on the openness of the fabric. Awnings and sunshades that extend horizontally above a window work well when the sun is high in the sky, such as around midday in the summer.

Interior sun protection as an addition

Interior sun protection, such as reflective roller blinds or thermal curtains, can somewhat limit heat transfer from the glass into the room. They provide an extra layer of insulation but are never as effective as exterior sun protection. Use them as a supplement, not as a replacement. Reflective film on windows is a cheaper option that also has some effect, but affects the aesthetics of your interior.

Where should you place an air conditioner in a home with many windows?

Preferably, place the indoor unit of an air conditioner on the wall opposite or next to the largest window, but never directly in bright sunlight or directly above a heat source. The cold air must be able to reach the room evenly. A position high on the wall works well because cold air naturally sinks and thus cools the entire room.

Avoid placing the unit directly above windows or doors that are frequently opened. Heat entering through these openings is immediately picked up by the air conditioner as warm air, causing the device to work harder than necessary. The outdoor unit also deserves attention: it must be placed in the shade or in a location where it is not heated directly by the sun. An outdoor unit in full sun performs less well and consumes more power.

In open living spaces with a lot of glass, it is smart to direct the air conditioning airflow to the zone where people spend the most time, rather than trying to cool the entire room evenly. That is more efficient and comfortable.

How do you prevent your air conditioner from becoming overloaded by solar heat?

You prevent overloading your air conditioner by limiting heat input, properly maintaining the unit, and matching the power output to the room. An air conditioner that runs continuously at maximum capacity because solar heat is not being blocked wears out faster and consumes unnecessary energy. A combination of measures is most effective.

Practical steps to prevent overload:

Install exterior sun shading so that heat ingress through the windows is blocked from the outside.
Ventilate at night by opening windows when the outside temperature is lower than the inside, so that the air conditioning does not have to work as hard during the day.
Close windows and doors as soon as the air conditioning is on, otherwise it cools the outside air as well.
Clean the filters regularly, because clogged filters reduce efficiency and increase the load on the system.
Set the thermostat to a realistic levelA difference of 6 to 8 degrees compared to the outside temperature is achievable without overloading.
Choose an air conditioner with the right capacity for the space, being too small is just as problematic as being too big.

A properly adjusted and correctly sized air conditioner combined with sun protection makes the difference between a unit that runs trouble-free for years and one that needs replacing after just a few summers. View via the pricing tool what an installation costs in your situation.

How De Betonboorder helps install air conditioning in a glass home

Installing an air conditioner in a home with many windows requires more than just hanging an indoor unit. Holes must be drilled through walls, facades, or floors for the air conditioner's piping. That is exactly where we, as specialists, make the difference.

Professional drilling of through holes for air conditioning pipes, also in reinforced concrete, aerated concrete and masonry.
Minimal damage by using high-quality diamond core drills that operate precisely without cracking or damaging the surrounding structure.
Neat finish of the workplace, so that you don't have to clean up a mess after the installation.
Rapid deploymentIn many cases, we can schedule a professional for you within two days.
National coverage through our network of experienced professionals, so even if you live outside the Randstad.

Do you want to have your air conditioner installed quickly and professionally? Contact us and we will respond within 24 hours with a suitable solution for your situation.

Air conditioning in a home with many windows: how to prevent a greenhouse effect