Window Replacement in Old Buildings: Tenant Rights Germany

Many tenants in Germany face the question of when landlords may legally justify window replacement in old buildings and who bears the costs. This text explains in plain language what modernization notices are legally required, which deadlines apply and how any rent increase due to modernization expenses is calculated. We show which rights and obligations tenants have, how to document defects and energy-saving potential, and when a rent reduction or court clarification makes sense. Practical wording aids, information about the competent courts and official sources help you act confidently and protect your rights in Germany.

What tenants need to know

A window replacement can be a modernization measure if it sustainably saves energy or improves the quality of the dwelling. Modernizations may allow the landlord to allocate part of the costs to the rent; the legal basis for cost allocation in modernizations can be found in § 559 BGB^[1]. Nevertheless, the form, content and deadlines of the announcement must be strictly observed so that tenants can check their rights.

Independent of modernization obligations, the landlord remains obliged to maintain the rental property (§ 535 BGB)^[2]. That means: replacement due to obvious defects or lack of usability is the landlord's responsibility, not the tenant's. If the window replacement is both defect remediation and modernization, the reasons must be given in writing.

If landlords issue termination or the window replacement is associated with a permanent rent increase, courts can be involved; proceedings run before the local district court or regional court, and for fundamental legal questions the Federal Court of Justice decides (BGH)^[3].

Practical steps for tenants

• Check the modernization notice for details on duration, type of work and expected rent increase.
• Document existing defects before and after the replacement with photos and dates.
• Ask for energy savings evidence and technical specifications of the new windows.
• Agree on deadlines and execution times, including quiet hours and apartment access.
• Seek legal advice if deadlines are not met or information is missing.

FAQ

Who pays for the window replacement?

For modernization, the landlord can allocate parts of the costs to the rent (see § 559 BGB). If it is purely defect remediation, the landlord remains liable.^[1]

Can the landlord simply install new windows?

No. For modernizations, the landlord must announce the works, meet deadlines and justify the measure. Tenants can object and seek judicial clarification if in doubt.^[2]

What can I do if the replacement causes defects?

Document damage, report it in writing immediately and request remediation. In case of dispute the local court can help; for urgent cases court proceedings under the ZPO are possible.^[3]

How-To

1. Request a complete modernization notice by letter or email with schedule and cost estimate.
2. Check whether the measure is modernization or defect remediation; record evidence and photos.
3. Agree on deadlines and execution times, especially quiet hours and access to the apartment.
4. Negotiate in writing about possible rent increases and request documentation of costs and energy savings.
5. If no agreement is reached, consider formal legal advice or filing suit at the local court; enforcement matters are governed by the ZPO.

Help and Support

• BGB §559 – Gesetze im Internet (Modernization cost allocation)
• BGB §535 – Gesetze im Internet (Landlord duties)
• Federal Court of Justice (BGH) – case law on tenancy

1. [1] BGB §559 — Gesetze im Internet
2. [2] BGB §535 — Gesetze im Internet
3. [3] ZPO — Gesetze im Internet