Summer heat can significantly reduce the quality of life in the house and apartment. Read how to keep the heat out – with our tips on heat protection in summer.
When the summer sun shines mercilessly, the temperatures in the apartment quickly climb to over 30 ° C. There are a few tips and tricks to prevent this. We have put together the best ideas for heat protection in summer for you.
Heat protection in summer
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How much a room heats up depends first of all on its orientation towards the sun: Record temperatures are created where the sun’s rays hit window surfaces, facades or roofs unhindered at steep angles. Heat protection is therefore particularly important in attic spaces.
On the other floors, it is not always the south-facing rooms where the heat is: the rays of the sun often just touch them due to the high position of the sun in summer. Horizontal panels such as canopies, balconies or deep window reveals further reduce solar radiation.
The east and west rooms of the building, on the other hand, often heat up more quickly. Due to the lower position of the sun, more shallow rays of the sun penetrate deep into the room.
Not only direct sunlight plays a role: Both the visible radiation of the sun, i.e. the light, and its thermal radiation are reflected from the surroundings of the building – for example from a nearby light-colored wall or glass facade, but also from a light floor covering.

Heat protection through thermal insulation
The heat penetrates less into the building through a roof or a facade with good thermal insulation than through inadequate thermal insulation.
There are definitely differences when it comes to the effect of different materials. Regardless of the material, modern insulation is half the battle, the heat absorption is reduced in any case.
Heat protection on the window
If the insulation in the roof and wall is correct, the windows are the only entry points for sun rays and heat. The proportion of thermal radiation that can pass through it into the room depends initially on the type of glazing and can be recognized by the so-called g-value (total energy transmittance).
The smaller this value, the better the heat protection properties of glazing. Commercially available heat protection glass has a g value of around 0.6. This means that 60% of the solar energy comes through the window.
However, there is also special solar control glass with a g value of up to 0.18. Such glass reduces the radiation either by absorption or by reflection of the sunlight.
In the case of absorption glass, dyes (e.g. iron oxide, copper oxide) are added to the molten glass. Glass that reflects in the visible and invisible areas is coated with a firmly adhering film. For this purpose, metal compounds are often vapor-deposited very thinly.
Sun protection films have a similar effect. They are usually tinted and can also be applied later. However, it must be remembered that the films keep heat and light out even in winter. Sun protection films are good value for money, but difficult to apply.

Heat protection through additional shading
Shading between the window panes is almost perfect. They are effective, maintenance free and do not need cleaning. Supplementary artificial shading is particularly effective in rooms exposed to the sun.
External shutters and blinds are particularly suitable. They prevent the sun’s rays from hitting the pane and reduce the heat input by up to 5%. Roller shutters also offer good protection against heat loss in winter and against burglars.
One disadvantage: the closed roller shutters do not let light through. External blinds are more suitable here, which can also be easily retrofitted.
Awnings, on the other hand, have significant disadvantages: They are less effective and also susceptible to wind, which also applies to the much more expensive awning.
All sun protection measures attached to the outside of the building require regular maintenance and are easily soiled. And: They change the overall visual impression of the house. Tenants therefore need the owner’s permission before installation.
Heat protection from the inside
Blinds, pleated blinds or curtains attached to the inside of the window are significantly less effective than external shading: They would have to reflect the radiation that has already penetrated outwards. This is hardly possible, especially with coated heat protection or sun protection glazing.
Internal shading is still useful. According to the manufacturer Warema, in combination with thermal insulation glass, they reduce the amount of heat that gets into the room by up to 30 percent.
Pleated blinds and the like are usually cheaper and easy to assemble for the do-it-yourselfer. They must not be attached too close to the window to prevent heat accumulation.
Heat-insulating glass with integrated shading is expensive, but low-maintenance and easy to care for: the slats are installed between the panes. Regardless of where the shading slats or surfaces are attached – they should be light or metal-coated: This way they can reflect sunlight and, above all, the heat of the sun particularly well.

Shadows as heat protection
However, the best shading system is only useful if it is used effectively. If you leave the house in the morning, you have to close the shutters or blinds on all windows that the sun wanders past during the day.
The shading is used more appropriately if it is controlled with the help of light and weather sensors. Such sensors are even indispensable for awnings that are susceptible to wind.
However, comfort has its price and also makes high demands on experienced do-it-yourselfers. It is better to have the heat protection installed by a specialist.
Midnight ventilation removes heat
Once the heat is in the apartment, it takes a lot of effort to get rid of it. The best and cheapest recipe is proper ventilation. As long as the sun is shining, the windows must remain closed – even with the shutters closed.
It is best to ventilate thoroughly in the morning and in the evening.
A combination of transverse and vertical ventilation has proven itself: warm air is let out through skylights so that cool air flows in below.
If you have problems with insects, fly screens or, if necessary, a mosquito net can quickly help.
A fan that is as silent as possible can also be used as a support. However, it must be placed in such a way that you are not directly exposed to the draft while sleeping. Otherwise unpleasant tension or annoying summer colds will result.

Room air conditioners as heat protection
At first glance, an air conditioner is an ideal aid. In principle, such a device works like a refrigerator: the interaction of the evaporator with fan, compressor, condenser and coolant transports the heat from the cooled room to the outside.
Room air conditioners use a lot of electricity. In the summer months, the monthly electricity costs can rise to 30 to 50 dollars.
Another disadvantage is the noise pollution: the monoblock device hums loudly enough to rob you of sleep, with a split device, on the other hand, the main source of noise, the compressor, is located outside the room – often to the annoyance of the neighbors. In any case, low operating noise is an important criterion.
The performance of the room air conditioners is also not always satisfactory. One-piece blows warm air and moisture out through a hose tucked into a window or door. Warm air from outside enters the room through this gap.
According to Stiftung Warentest, the connection hose between the indoor and outdoor units is much better insulated in two-piece models. Ideally, it is led through a hole in the outer wall. However, this also requires the landlord’s consent. In addition, since 2008 split devices are no longer for do-it-yourselfers, because they can only be installed by a specialist company, which increases the purchase price even more.
It should be noted that air conditioning units require care and maintenance: filter cleaning and condensate disposal are part of their operation. But if you don’t shy away from expense or effort, this is the most comfortable way to provide heat protection at home.
Seven home remedies for heat protection
- All additional heat sources – electrical appliances, televisions, lighting and computers – stay off when they are not needed.
- Moist cloths, hung in front of the window, provide relief and at the same time keep bloodthirsty mosquitoes away.
- Moderate endurance exercise before going to bed makes you tired.
- Since an overloaded stomach sleeps poorly, only light food should be on the table in the evening. Alcohol may make you tired, but it makes for a restless sleep. Therefore, drink in moderation.
- A lukewarm shower opens the pores. So the heat doesn’t build up so easily in the body. Don’t dry yourself off too thoroughly: The evaporation of the water cools the body naturally.
- Thin, light bed linen protects against drafts, but does not store body heat unnecessarily. Bed linen made from natural silk or with a high proportion of natural silk has a pleasantly cooling effect. Synthetic fibers, on the other hand, are taboo. Pre-cooled gel cushions act like small ice packs.
- When the night turns tropical: Pre-cool your nightwear in the refrigerator to help you fall asleep.