Plastic windows

Plastic windows are windows whose frames are made of polyvinyl chloride (PVC) or another type of plastic profile. Today, they are the best-selling window system in Germany because they offer good thermal insulation at a low price, require little maintenance, and are available in almost any color. They are frequently used as an alternative to wood or aluminum windows in renovation projects and new construction.

Features and Benefits of Plastic Windows

Plastic windows offer compelling advantages in many areas:

• Thermal Insulation: Modern multi-chamber PVC profiles achieve Uw values (total U-value of the window including glazing) below 1.0 W/(m²·K)-thus easily meeting EnEV and GEG requirements
• Ease of maintenance: PVC does not weather, does not need to be painted, and can be cleaned with a mild detergent
• Sound insulation: Multiple glazing (double or triple glazing) offers good noise protection (Rw up to 42 dB possible)
• Cost-effectiveness: Generally 20 to 40% cheaper to purchase compared to wood or aluminum windows

Advances in profile technology have made significant strides in recent years: Modern six- and eight-chamber profiles achieve thermal insulation values that were reserved for special applications just ten years ago. Thanks to steel reinforcement in the profile chambers, PVC windows are also structurally sound and suitable for large window sizes.

Sustainability and Life Cycle

The sustainability debate surrounding PVC is complex: On the one hand, the production of PVC profiles generates significant CO₂ emissions; on the other hand, the material is easily recyclable after 30-40 years of use, and the energy savings from improved thermal insulation clearly outweigh the environmental impact when considering the entire life cycle. In recent decades, the window industry has switched to lead-free stabilizers (calcium-zinc stabilizers), which has improved the environmental footprint.

Disadvantages and Limitations

Despite their advantages, there are limitations:

• Historic Preservation: Plastic windows are often not permitted in historic buildings; authorities frequently require wooden frames or special profiles
• Recycling: PVC recycling is more complex than for aluminum; however, a service life of 30-40 years is routinely achieved
• Aesthetics in historic buildings: Smooth PVC surfaces often look out of place on older buildings; wood-grain films offer a compromise but rarely satisfy historic preservation authorities

Plastic Windows in the Energy Performance Certificate and GEG

The Building Energy Act (GEG 2023) sets minimum requirements for the thermal insulation of windows. Anyone replacing windows should aim for a U-value of no more than 1.3 W/(m²·K). Triple-glazed plastic windows, with a U-value of approximately 0.8 W/(m²·K), fall well below this threshold and can meet KfW funding requirements (e.g., Program 261, BEG EM).

When replacing windows in existing buildings, an important side effect must be considered: Highly insulated windows reduce heat transfer and the associated air drying so significantly that the risk of condensation on other, less insulated building components (roller shutter boxes, window reveals) increases. Professional installation with joint sealing in accordance with the RAL quality mark and, if necessary, additional insulation of the reveals are therefore essential.

Practical Tip for Homeowners in Nuremberg and Franconia

When replacing windows in existing buildings in Nuremberg, homeowners should first check whether the building is located in a historic preservation district or subject to design regulations. For most Wilhelminian-style houses near the city center (Gostenhof, St. Johannis, Steinbühl), white or laminated plastic windows are eligible for approval; in the Old Town, however, strict regulations apply. We also recommend submitting grant applications (BAFA, KfW) before hiring a specialist contractor-funding is no longer available retroactively. It’s worth comparing at least three quotes: Price differences for comparable plastic windows can vary significantly among different providers in Nuremberg.

Window Replacement and Condominium Law

In apartment buildings and homeowners’ associations, the question arises regarding window replacement: who is responsible and who bears the costs? According to the Condominium Act (WEG), windows-that is, frames, glazing, and hardware-are considered common property, even if they are located in the exterior walls of an individual unit. This means that an owner may not replace their windows on their own initiative, even if they wish to cover the costs themselves. A resolution by the owners’ meeting is required.

In practice, this often leads to tensions when individual owners wish to modernize for energy efficiency, but the community does not go along with it. Since the 2020 WEG reform, the legal situation has improved somewhat: Under certain conditions, individual owners may carry out structural changes at their own expense if they do not unduly inconvenience the others. However, this is generally not sufficient for a complete window replacement-a resolution remains the safest course of action. We recommend putting the topic on the agenda as part of the condominium association’s annual planning and obtaining quotes collectively to take advantage of economies of scale.

Frequently Asked Questions

How long do PVC windows last?

With professional installation and regular maintenance of the hardware (annual oiling of the hinges), PVC windows will last reliably for 30 to 40 years. After about 20 years, seals may wear out and may need to be replaced.

Can I replace the windows in my condominium at my own expense?

In a condominium association, windows are generally considered common property. Unauthorized replacement without a resolution from the owners’ association is therefore not permitted. Bring up the topic at the next owners’ meeting.

Are plastic windows mandatory in a KfW Efficiency House?

No-the window material is not specified. The U-value is the deciding factor. Whether wood, aluminum, or plastic: all materials can provide KfW-compliant windows, provided the thermal requirements are met.

What is the average cost of replacing windows in the Nuremberg region?

Costs vary depending on window size, profile system, and installation conditions. As a rough guide: A standard apartment window (approx. 1.0 × 1.2 m) with triple glazing and installation typically costs €800-1,400 in the Nuremberg metropolitan area. Basement windows, skylights, and complex custom shapes are more expensive.

Can I apply for subsidies when replacing windows?

Yes. The replacement of old windows with models featuring a high thermal insulation value (Uw ≤ 0.95 W/(m²·K)) is subsidized by the Federal Office for Economic Affairs and Export Control (BAFA) under the Federal Subsidy Program for Efficient Buildings - Individual Measures (BEG EM). The subsidy application must be submitted before commissioning the specialist contractor; retroactive applications are not permitted. The subsidy rate is currently 15% of eligible costs; with an Individual Renovation Roadmap (iSFP), up to 20% can be achieved.

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