Sun shading: an effective tool against overheating

The importance of coordinated sun shading becomes particularly clear when protecting against heat in the summer. RTG (Repräsentanz Transparente Gebäudehülle) has commissioned several studies by the renowned engineering firm Ingenieurbüro Prof. Dr. Hauser (IBH) on the efficacy of sun shading. In its latest study, IBH 4* (based on a predefined generic test room with around 45 m² of floor space and a south-facing window area of around 36% of the room floor space), calculations show the great potential offered by external sun shading and an intelligent control system: conventional use of sun shading reduces the number of hours with interior temperatures of over 26°C from 2,781 hours (without sun shading) to 512 hours over the course of the year. If the automated system activates the sun shading early on, this drops to 212 hours. When this is combined with night-time ventilation, the number of hours above 26°C can be reduced to just 39.

Thinking of sun shading and windows as a system

To adapt existing buildings to the consequences of climate change, windows and sun shading should be viewed as a system. This is the only way to optimise their energy potential. The building components significant to energy transmittance – glazing and sun shading – are included in an overall energy value: the total solar energy transmittance (gtot). Precisely coordinating both components allows the incidence of energy to be optimised during both cool and hot periods.

Another benefit of viewing it all as one system is that the window’s heat transmission coefficient is improved when sun shading is used as temporary thermal protection. On winter nights, closing the sun shading can reduce the energy lost through the window by up to 37% (additional thermal resistance of a roller shutter in combination with an existing window with a heat transmission coefficient of Uw=2.7W/(m²K)). Even modern triple glazing can only reduce energy loss by up to 16%. This calculation is based on the additional thermal resistance of a roller shutter in combination with triple heat protection glazing with a heat transmission coefficient of 0.86 W/(m²K).

The comfort of the home can also be increased. Using suitable sun shading such as an external venetian blind can optimise the daylight that enters the space. Depending on the specific requirements, the flexible slat angle can provide effective glare protection or privacy as well as a good view of the outside. A window awning’s properties depend on the fabric selected, so it’s worth thinking about how it is going to be used. Roller shutters also boost living comfort by protecting against overheating in the summer and reducing heat loss in the cooler months. The various sun shading products can also be combined to fulfil the specifications required for every room.

Sun shading for increasing weather extremes

These days, sun shading needs to do much more than just protect against summer heat. Climate change is resulting in hotter summers – both day and night – and longer periods of warm weather. Wind loads and heavy rainfall are also increasing. This raises expectations of functionality and stability and increases demand for systems that are reliable, watertight against driving rain and last a long time. Outdoor living is also becoming more and more important, increasing the focus on reliable insect and pollen protection.

When planning and executing a project, this means that the materials, construction and design have to be adapted to the changes in climatic conditions. For example, material stress due to rising heat exposure has to be taken into account. This places more emphasis on aspects such as choosing between plastic and aluminium and how a material behaves in extreme conditions. More intense UV radiation also requires new quality standards in surface coating. Depending on where a product will be used, highly weather-resistant coatings will be needed.

With all this in mind, renovating energy systems takes on a central role in achieving climate goals in existing buildings. It also has great potential for adapting existing buildings to these changing requirements.

Flexible system solutions for different renovation situations

For practical implementation – particularly when carrying out energy-efficient refurbishment of a building – Warema offers future-proof system solutions that treat sun shading as a functional part of the building envelope and are aligned with the changing climatic conditions. The focus is on flexible systems for various construction situations that have a high level of pre-assembly and are easy to install – useful given the increasing lack of skilled workers. These include front-mounted and shaft solutions for external venetian blinds, roller shutters and versatile window awnings. The portfolio is complemented by modular function packages that can be easily integrated into the sun shading products. Warema SecuKit is a good example of this. Allowing window awnings, roller shutters and external venetian blinds to be operated manually, it provides quick and reliable access to escape and emergency routes in the event of danger or a power failure. Another is the SolarKit for retrofitting roller shutters and window awnings with a self-sufficient energy source. This can be operated independent of the network via an integrated solar panel. The VisioNeo Sun railing system combines design freedom and verified safety for floor-to-ceiling windows and is available in various designs, from glass to rail to combined systems. Warema also offers a wide range of effective insect protection solutions that are simple to integrate between the window and sun shading.

All of the additional solutions mentioned enable window construction partners to generate attractive additional sales and specifically reduce interfaces between tradespersons. End customers benefit from additional comfort, safety and energy efficiency above all else.

Automation: the key to effectiveness

For sun shading systems to actually be effective, they must be selected and constructed professionally. How they interact with the window is also crucial. Intelligent control systems allow them to be automatically adjusted to external factors, help to protect the sun shading and support efficient energy management in the building. Paying attention to usage times is another tool that often goes unused: presence detectors and information on work days, weekends, public holidays and vacations can be used to manage rooms as needed.

* Study on the integrated evaluation of summer heat behaviour (developed by Ingenieurbüro Prof. Dr. Hauser GmbH on behalf of Repräsentanz Transparente Gebäudehülle GbR)

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