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16.09.2025

Energy-efficient window refurbishment: all information at a glance

Beautiful old building, renovated with ROMA sun shading

Energy-efficient window refurbishment is one of the most effective measures for reducing energy losses in buildings - while improving living comfort, indoor climate and sustainability. With its external sun shading systems such as Roller Shutters, ExternalVenetian Blinds and Textile Screens, ROMA offers intelligent solutions that can be perfectly integrated into a renovation concept. In this article, you will learn everything you need to know about requirements, U-value, funding opportunities and implementation.

Find the right ROMA specialist partner in your area now:

Energy-efficient window refurbishment: the most important facts in brief

  • Saving energy by replacing windows: Energy-efficient window refurbishment reduces energy consumption in the long term and improves the indoor climate.

  • Take advantage of attractive funding opportunities: Subsidies from BAFA or KfW reduce investment costs and make refurbishment measures more economical.

  • Sun protection as an efficiency factor: External sun protection systems such as Roller Shutters, External Venetian Blinds or Textile Screens make a significant contribution to thermal insulation - in summer and winter.

  • U-value as a measure of efficiency: The heat transfer coefficient of a window determines how much heat escapes - the lower the U-value, the better the insulation performance.

Why windows are so important for energy-efficient refurbishment

From an energy point of view,windows are weak points in the building envelope. Outdated glazing and inadequate frame insulation lead to heat loss in winter and overheating in summer. An energy-efficient renovation of these components provides a remedy - and increases the value of your property at the same time.

The measure is particularly effective in combination with external solar shading, as this has a positive effect on the indoor climate all year round: The heat stays inside in winter and outside in summer.

Requirements for the energy-efficient refurbishment of windows

If you want to meet the requirements for energy-efficient window refurbishment, you should consider the following aspects:

  • Modernize glazing: Replacing outdated single or double glazing with energy-efficient thermal insulation glazing is essential.

  • Use thermally insulated frames: High-quality frame profiles with optimized insulation values significantly improve the overall balance of the window.

  • Ensure professional installation: An airtight, thermal bridge-free installation in accordance with RAL guidelines is a prerequisite for the measure to be fully effective.

  • Add sun protection intelligently: External systems such as ROMA Roller Shutters or External Venetian Blinds increase the energy effect - especially in combination with Smart Home control of the sun shading system.

Tip

The direction of the windows and the physical properties of the façade also influence the renovation concept - individual specialist advice is therefore recommended.

What does the U-value mean for windows?

The U-value (heat transfer coefficient) is a key parameter in the energy-efficient refurbishment of windows. It describes how much heat is lost to the outside through a component - such as a window. The lower the U-value, the better the insulating effect and therefore the greater the energy efficiency.

Component
Typical U-value (in W/m²K)
Single glazing
approx. 5.0
Insulating glazing (old)
approx. 3.0
Thermal insulation glazing (new)
approx. 1.1-1.3
Passive house windows
≤ 0,8

Optimizing the U-value when renovating windows is a decisive step towards reducing energy requirements. In addition, the use of ROMA solar shading systems - such as Roller Shutters, Venetian blinds or Textile Screens - significantly increases the energy efficiency even further: in summer by reducing the heat input, in winter by reducing heat loss when the elements are closed.

Funding for the energy-efficient renovation of windows: how you benefit

The German government supports energy-efficient renovations through various programs:

  • BAFA funding: for individual measures such as window replacement and external sun protection

  • KfW funding: as part of an efficiency house standard

  • Tax write-off: up to 20% of the refurbishment costs over three years

The prerequisite for the subsidy is that the refurbishment must be carried out professionally and accompanied by an energy consultant. Use the ROMA BAFA subsidy assistant to check whether your measure is eligible for a subsidy in just a few minutes.

Eat-in kitchen with large window and Textile Screens from ROMA

What role does external sun shading play?

An often underestimated factor in window refurbishment is solar shading. This is because it not only acts as a heat shield in summer, but also influences the energy balance all year round:

Advantages of external sun shading with ROMA

  • Reduction of cooling costs in summer

  • Avoidance of overheating with large window areas

  • Optimization of daylight entry through controllable slats

  • Improved sound insulation and privacy

  • Compatible with Smart Home solutions

External sun shading therefore makes a significant contribution to the energy-efficient refurbishment of windows - in terms of technology, design and living comfort. Anyone who wants to reduce energy costs in the long term, improve the indoor climate and at the same time focus on high-quality design is making a future-proof decision with ROMA sun shading systems.

ROMA solutions for your window renovation

ROMA offers a wide range of sun shading systems that can be ideally integrated into energy-efficient refurbishment projects:

Energy-efficient window refurbishment pays off twice over: it reduces energy costs and increases living comfort - especially in combination with intelligent, external sun shading from ROMA. Whether new build or renovation - with ROMA you are making a decision for quality, durability and efficiency "Made in Germany".

Getadvice now and find the right ROMA specialist partner in your area!

Frequently asked questions (FAQ) about energy-efficient window refurbishment

What is included in the energy-efficient refurbishment of windows?

Energy-efficient refurbishment involves replacing old glazing with modern thermal insulation windows, professionally insulating the connection areas and ensuring airtight installation. In addition, external sun protection significantly improves energy efficiency by keeping the heat out in summer and minimizing heat loss in winter.

What are the requirements for funding?

The measure must be effective in terms of energy efficiency - this is confirmed by an energy consultant as part of an individual renovation roadmap or specialist planning. Windows and external sun protection must meet defined minimum technical requirements, for example with regard to the U-value or thermal insulation in summer. It is also important that the work is carried out by a qualified specialist company and that funding is applied for before the measure begins.

What U-value is recommended for refurbishment?

A maximum U-value of 1.3 W/m²K is recommended for the energy-efficient refurbishment of windows - this corresponds to the current standard for energy-efficient buildings. If you want to renovate in a particularly sustainable way, you can opt for passive house windows with a U-value of ≤ 0.8, which offer maximum insulation and reduce energy costs in the long term.

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