Replacing windows in an Altbau: what it really costs in 2026

Window replacement is the most expensive — and most consequential — single upgrade in an Altbau apartment, and the one where the most money gets wasted. Without knowing the going rates, you typically overpay by 20–30%. Here are the numbers tradespeople rarely volunteer.

The price basis: what does one window cost?

For a typical 3-room Altbau flat with six to eight windows, the total lands between €6,000 and €18,000 depending on material. Add 10–15% for shutters, interior sills and repainting around the frames.

Subsidies: the state pays along

Under KfW 264 (BEG), fitting triple-glazed or heritage-appropriate windows usually earns a 15% grant (up to €30,000 eligible cost per unit), rising to up to 25% with the renovation-roadmap bonus. Crucial: apply before awarding the contract — retroactive claims get nothing.

Three rules that save you thousands

1. Three quotes, identical line items. Demand an itemized list (dimensions, glazing, U-value, extras) — it's the only way quotes are comparable. Lump-sum quotes are almost always pricier.
2. Winter and quarter-end are discount seasons. Tradespeople hunt for jobs between November and February and at quarter-end — asking is worth 5–10%.
3. Wood over uPVC where the fabric deserves it. Good wooden windows last 50+ years, uPVC 25–30. Over their lifetime, wood is almost always cheaper — and the only choice that matches Altbau character.

Note: All prices are researched indicative values (as of October 2026) and vary by region, window size and building condition. This article contains no paid recommendations.