§ Heat pumps · Updated: 22 July 2026 · Published by: KEY-FI · 6 min read
Heat pumps in Germany: check the building, cost and support
Review insulation, heat distribution, flow temperature, electricity use and current KfW support before planning a heat pump for an existing home.
A heat pump cannot be judged by the appliance price alone. The building's heat demand, insulation, radiators or underfloor heating, required flow temperature and electricity tariff affect both comfort and running cost.
Start with the building
Collect the living area, construction year, renovation history and recent fuel consumption. A heating-load calculation and a review of the heat-distribution system are more useful than a rule based only on the age of the property. Older buildings can be suitable, but the technical conditions need to be checked.
Understand efficiency in practice
The annual performance factor describes how much heat the system produces in relation to the electricity used over a year. It depends on the heat source, system design, flow temperature, hot-water demand and operation. A brochure value is not a promise for a particular home.
Include the full project cost
Planning should cover the unit, installation, electrical work, hydraulic balancing, any changes to radiators or pipework and possible work around the outdoor unit. Keep a contingency for findings that only appear during detailed planning.
Check support before starting
The current KfW heating support for private owners sets out eligible measures, applicants, conditions and the application process. Funding is subject to the current programme and available budget. Obtain the required confirmation and follow the application order before committing to work.
Questions for the first review
- What flow temperature was needed on cold days?
- Which rooms are difficult to heat?
- Are radiators or surfaces large enough for lower temperatures?
- How much fuel did the building use in recent years?
- Where can indoor and outdoor components be installed?
- Which renovation work is planned at the same time?
An initial check does not replace engineering or an installer quotation. It helps identify the information a specialist will need.
Use the heat pump suitability page to prepare the building details.
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