Guide
8 min
Aug 28, 2026
Retrofitting a 1910 building to EPC B
Windows, insulation and a heat pump: what it cost and what tenants save.
Lena Hoffmann
Asset management
Looks after boilers, roofs and leases in our fourteen Berlin buildings.
EPC B
the rating a 1910 building can reach with the right works
Where we started
Our oldest Berlin buildings were rated E or F when we bought them: single glazing, uninsulated roofs and gas boilers in every apartment.
Retrofitting them is not about a single big project. It is a sequence of works, each done when it costs the tenants the least disruption.
The order of the works
We start with the roof and the top-floor ceilings, then the windows, then a shared heat pump in the courtyard. Facades on listed streets stay as they are and are insulated from the inside.
Done in that order, a 1910 building can reach an EPC B rating. Tenants pay less for heating, and the building is protected from the stricter rent rules on poorly rated homes.
Every retrofit is paid for from the fund’s reserve and repair budget, never by cutting a monthly payout.
02·L
In this letter
3 takeaways
Key takeaways.
Roof first, then windows, then a shared heat pump.
A 1910 building can reach EPC B without touching a listed facade.
Works are paid from the reserve, never from a payout.
