Summer thermal insulation ensures that your interiors remain pleasantly cool even on hot days - without the need for energy-intensive air conditioning systems. High temperatures and heated living spaces don't have to be a thing of the past: whether in new builds or renovations - if you take appropriate measures in good time, you can effectively limit heat development through windows, roofs and façades and save energy in the long term.
It is worth taking a look at modern solutions such as external Venetian Blinds systems or textile shading using Textile Screens. ROMA offers individual systems that are not only functional but also aesthetically pleasing. In this article, you will find out what constitutes thermal insulation in summer, which regulations apply and which measures really work.
Checklist: Measures for thermal insulation in summer
What does summer thermal insulation mean?
Why is summer heat protection so important?
What measures are effective against summer heat?
Calculating summer heat insulation: Practical example
Check BAFA funding for summer heat insulation
Clever implementation of thermal insulation with ROMA
Frequently asked questions (FAQ) about thermal insulation in summer
Equip windows with solar control glazing or films
Retrofit external Venetian Blinds or Textile Screens
Ensure sufficient shading on south/west-facing sides
Plan for light façade colors and green roofs
Actively use night cooling
Equip roof windows with special heat protection
Summer thermal insulation includes all structural and technical measures that prevent interior rooms from heating up too much due to solar radiation. Especially with large window areas, south-facing orientation or poorly shaded attics, temperatures can quickly become uncomfortable - particularly during frequent heat waves.
Summer thermal insulation is legally regulated in DIN 4108-2. This standard defines requirements for rooms that are exposed to a high solar load. The aim is to prevent overheating without active cooling.
Factors such as window area, room volume, orientation and overhang angle also play a role in the calculation.
There are two variants depending on the building type:
Simplified verification: using characteristic values such as window proportion, orientation and shading.
Dynamic verification: with simulation of the room temperature throughout the day, for more complex buildings.
If the summer thermal insulation is not met, structural measures or improvements are required.
Certain characteristic values are crucial for the structural verification of thermal insulation in summer. They help to objectively evaluate and specifically optimize the effectiveness of glazing and shading elements.
G-value: indicates how much solar energy enters the building through the glazing. The lower the value, the better the protection.
FC value: describes the effectiveness of the solar shading. For example, an external Venetian Blinds achieves FC values of 0.10 to 0.25. Textile Screens achieve 0 to 0.32, depending on the choice of fabric.
Overhang angle: Angle of a fixed component (e.g. balcony slab) that influences the shading.
These values help building owners to take specific measures and implement summer thermal insulation in accordance with standards.
Effective thermal insulation in summer not only increases living comfort - it also protects health, reduces energy costs and makes buildings future-proof. In poorly protected rooms, the indoor temperature can quickly rise above 30 degrees. This not only puts a strain on the circulation, but also on performance.
In addition, the increasing number of hot days leads to a growing demand for air conditioning units - with correspondingly high electricity consumption. Those who take structural measures at an early stage will reduce their cooling requirements in the long term and save energy costs. Summer thermal insulation is therefore a key component of sustainable construction.
(ROMA Architectural Consulting)
Effective thermal insulation starts at the planning stage - but many measures can also be implemented in existing buildings:
External Venetian Blinds, Textile Screens or Roller Shutters block the sun's rays before they hit the window glass.
Solar control glazing: reduces the G-value, but lets in less daylight.
Roof overhangs and greenery: passive shading through structural elements or plants.
Ventilation and night-time cooling: targeted ventilation in the morning and evening, keep windows closed during the day.
Internal sun protection: less effective, but sometimes useful as a supplement.
The so-called solar factor (Svorh.), which relates the potential heat input through window areas to the size of the room, helps to evaluate the thermal insulation in summer. The lower the value, the better the room is protected against overheating.
The solar gain value is calculated using the formula according to DIN 4108-2:
Svorh. = ∑Aw,J - gtot,j /AG
Svorh : solar gain value
Aw,J: Window area [m²]
gtot,j: Total energy transmittance (incl. sun protection)
AG: Net floor area of the room [m²]
Calculation example: What is the effect of external solar shading?
A 25 m² living room with two windows facing south-west has a total glazed area of 4.5 m². The windows are fitted with external solar shading, which reduces the total energy transmittance(gtot) to around 0.15. The solar gain value is calculated as follows:
Svorh. = (4.5 × 0.15) ÷ 25 = 0.027
This corresponds to a value of only 2.7% - and is therefore far below the limit value of 25% recommended in DIN 4108-2. The result shows: The room is well protected against overheating in summer, especially thanks to the external solar shading. Anyone planning a building project or carrying out a renovation should plan the thermal insulation with a Distributor at an early stage.
Well-designed summer heat protection is not only rewarded with greater living comfort, but can also be subsidized by the state under certain conditions - for example via the BAFA as part of the Federal Subsidy for Efficient Buildings (BEG). ROMA supports you with a practical subsidy assistant, which checks whether your solar shading system is eligible and guides you step by step through the application process.
Well thought-out thermal insulation in summer not only protects against overheated rooms, but also ensures greater comfort, energy efficiency and value retention in the long term. External blinds or Textile Screens are particularly effective - preferably automated and precisely tailored to the building.
ROMA offers high-quality, individually plannable solutions that have proven themselves in both new builds and renovations. Get advice now or find a specialist partner near you.
Winter thermal insulation keeps heat in the house - summer thermal insulation keeps heat out. Both aspects should be considered holistically in order to ensure a pleasant indoor climate and low energy costs all year round. High-quality insulation, modern windows with suitable glazing and external sun protection systems such as External Venetian Blinds or Textile Screens can efficiently combine both objectives.
External Venetian blinds are much more effective than internal sun protectionin summer, as the majority of solar radiation is intercepted outside the window pane. This means that considerably less heat enters the building. Internal systems such as roller blinds or curtains can reduce glare, but offer hardly any protection against heat input as the glass is already heated. External Venetian blinds with adjustable slats also allow flexible light control without having to sacrifice daylight - a clear advantage for comfort and energy efficiency.
Yes - state subsidies are available for summer heat protection, e.g. via BAFA as part of the BEG for external sun protection such as External Venetian Blinds, Textile Screens or Roller Shutters. ROMA supports you with the practical BAFA subsidy helper, which checks whether your system is eligible and guides you step by step through the application process.