How to make your home fit for high temperatures

Sustains the heat in the house is uncomfortable and can be harmful to our health. How to counteract this in new constructions and what can still be done later.

Peaceful sleeping? Impossible. Concentrated working? Maybe in the basement. During a heat wave, it will be nearly unbearable warm in many houses. However, there are possibilities to keep indoor temperatures pleasant.

Someone who energy-renovates their house is well prepared for heat periods. Because: What keeps the heat in the house in winter also makes sense in high temperatures. "Every energy improvement of the building has a positive effect on summer heat protection," says Klaus-Jürgen Edelhäuser of the Bavarian Chamber of Engineers-Building in Munich. "A good thermal insulation, preferably with insulation materials that have a high bulk density, keeps the house cool in the summer."

The reason for this is: The better a house is insulated, the more it reacts passively to external influences. "First, the building components absorb heat or cold, before it reaches the interior. This effect can be observed well in old churches," says Martin Persch, energy advisor of the Consumer Center Thüringen. "There, room temperatures are similar in summer as in winter because the thick walls offer a lot of heat storage capacity."

A concrete floor can be beneficial

The Consumer Centers recommend builders to plan as much heat storage capacity as possible when building new, that is, materials with a high specific heat capacity. This includes masonry and concrete walls or floor tiles. In the attic, multi-layered insulation made of building panels can provide more storage capacity. For the floor, a screed or a concrete floor is advantageous.

If the house shell, roof, and floor plate are insulated, that is already a good prerequisite to spend hot days comfortably. However, an important entry point for heat are still the windows. In a new building, one should consider this in the planning that they do not become too large. "Deep-set windows or glass facades let in a lot of heat into the house," says Klaus-Jürgen Edelhäuser. In view of the climate changes, this could be problematic. "It is better to build today so that it meets the environmental conditions in 30 years."

Deep-set windows or glass facades let in a lot of heat into the house

The Association of Windows + Facades in Frankfurt am Main points to various ways to prevent overheating of living spaces in the summer, such as the installation of special windows with sun protection glazing. But also sun protection films and above all external roll-down shades and awnings keep the heat outside.

"External sun protection is much more effective than internal roll-down shades or awnings because it prevents the heat from reaching the window glass in the first place," explains Klaus-Jürgen Edelhäuser.

Proper ventilation helps

He also recommends focusing not only on buildings themselves but also on the entire environment. "Someone who plants trees or creates a garden in front of their house benefits from the shade and evaporative cooling of the plants. Facade and roof greening also have a significant cooling effect." On the contrary, bare gravel gardens in front of the house attract heat and warm up the entire surroundings.

Proper ventilation can also contribute to keeping the heat out of indoor spaces. "Basically, cool air should be brought into the house in the summer," says Martin Persch. Therefore, it is best to ventilate in the late evening or early morning between five and seven o'clock. Important: complete air exchange.

On hot days, windows should be kept closed and the roll shades should remain at the bottom. "Cross ventilation as refreshment brings little. Opening the windows at high outdoor temperatures lets in only hot air from outside," says Klaus-Jürgen Edelhäuser.

The heat pump can also cool

A climate control system can be a helpful tool for particularly hot periods. "But only in a few cases is such a system really necessary if I consider the other heat protection measures," says Martin Persch. And someone who heats their home with a heat pump in the winter can save themselves the climate control system. Because a heat pump can also cool, and this passively through the heating system.

With ground source heat pumps, for example, the cooling effect is achieved by the heat pump using thermal energy from the earth. Temperatures in a depth of around 100 meters remain constant throughout the year at an average of ten degrees Celsius. "Water with this temperature can circulate through a surface heating system in the house and cool it down," explains Martin Persch. "Air-air heat pumps and water-water heat pumps can also be used for cooling."

To achieve energy efficiency in homes, the Federal Ministry of Economics promotes solar promotion programs, providing financial support for the installation of solar energy systems.
Consumers seeking advice on energy-efficient solutions can consult with advisors at KfW, a German development bank known for its work in environmental protection and climate change mitigation.
In the process of renovating an apartment, investing in energy-saving measures such as insulation, heat pumps, and solar panels can significantly reduce heating costs for consumers.
Real estate developers can leverage the expertise of energy advisors to ensure that new constructions meet high energy efficiency standards, promoting the use of materials like concrete and masonry with high thermal mass.
Consumer centers advocate for utilizing natural means to minimize heat absorption into buildings, such as planting trees, creating gardens, and implementing facade and roof greening to maintain comfortable indoor temperatures during summer.
As part of their offerings, some solar energy companies provide cooling services using heat pumps, which can be an energy-efficient alternative to traditional air conditioning systems, saving consumers money on cooling costs.
House owners considering the installation of heat pumps for heating can also benefit from using them for cooling during hot summer days, utilizing the thermal energy provided by the ground or water sources for passive cooling.