Heating an Altbau: gas boiler, heat pump or night storage?
Many Altbau apartments still run on night-storage heaters or 1970s oil boilers. Replacement is mandatory under the GEG's 65% rule — the only question is with what. The answer depends more on the building than the technology. Here's the honest comparison.
The head-to-head comparison
| System | Investment | Heat cost / year* |
|---|---|---|
| Gas condensing (transition) | 6.000–10.000 € | 1.400–2.200 € |
| Air-to-water heat pump | 12.000–20.000 € | 1.100–1.800 € |
| District heating (where available) | 5.000–9.000 € | 1.500–2.500 € |
| Night storage (status quo) | 0 € | 2.500–3.800 € |
*80 m² apartment, medium heat demand, prices as of 2026.
Altbau buildings with exposed brick store heat exceptionally well. That lowers flow temperature — and often makes heat pumps economical even without full insulation. Get a heat-demand calculation before anyone sells you a "necessary" full insulation package.
What the state subsidizes in 2026
- Heat pump (BEG-EMWG): 30% base grant, up to 5% efficiency bonus, up to 20% income bonus — up to 70% in total.
- District heating connection: municipal or BEG-WV grants, commonly 30–50%.
- Night-storage replacement: municipal programs (e.g. Berlin) sometimes add €5,000–10,000 on top of BEG money.
Our recommendation by scenario
- Owner-occupier, renovation-ready flat: heat pump with low flow temperatures + large radiators. Use the grants; payback typically 8–14 years.
- Rented flat, limited budget: district heating if available at the building — lowest investment, no plant in the basement, good marketability.
- Listed building, no alternatives: modern night-storage heaters running on surplus PV or a green tariff as a transition — yes, that's legitimate, as long as a renovation roadmap exists.
What does your heating swap cost in context?
Use our tool to estimate the total investment across all trades.
Open the calculatorNote: indicative values, not legal or investment advice. Subsidy terms change regularly — check current KfW conditions before applying. Questions for the editors: hello@altbau.com