Industrialised Retrofit in Germany

“The biggest barrier isn’t technical.”

That line, from Rafe Bertram’s Churchill Fellowship research, set the tone as Jon Warren, Director at Energiesprong UK, shared lessons from September’s Energiesprong Festival in Berlin.

A new industry in 15 years

Germany wants serial retrofit[1] to reach the mass market in 15 years, against 70 to 140 years for earlier technologies such as solar PV. A steady European policy ratchet helps: no subsidies for standalone fossil boilers from 2025, a carbon price on heating from 2028, zero emission new buildings from 2030 and fossil boilers phased out by 2040.

Facing a renovation rate below 1 per cent and skills shortages reported by 59 per cent of firms, Germany chose to industrialise. It now has around 6,000 homes done or on site, 17,000 in planning, a €3bn market and more than 1,000 active companies. Costs remain the big challenge: €1,500 to €1,800 per square metre today, targeting €750 to €1,200, compared with around £1,000 in Energiesprong UK’s latest trial. And Germany starts from a better baseline: its homes lose heat about three times more slowly than UK homes, the result of “decades of policy, funding and training”.

Five models for UK landlords

• Warm rent neutrality. Retrofit is judged on rent plus heating, which must stay flat for tenants, with post-retrofit rent rises capped per square metre.

• Percentage funding. KfW[2] offers rules based low interest loans with part written off for energy savings. “There’s a lot of bidding and winning and competition for grant funding, but Germany has none of that.”

• External insulation culture. Re-render more than 10 per cent of a wall and you must insulate it. With scaffolding already paid for, the extra cost roughly halves to €90 to €100 per square metre.

• Balcony solar. Germany has more than 1.4 million plug-in systems. Approved kits up to 800 W became legal in Great Britain in August 2026, and some landlords are already getting tenant requests.

• Tenant electricity. Landlords sell rooftop solar power directly to tenants, with specialists handling billing. An attendee noted UK licence exemptions already allow this, citing a Hackney project.

“The biggest thing Germany was doing was rolling in EWI along with the repairs and maintenance.”

Jon Warren, Energiesprong UK

What comes next

With the two to eight storey block cracked, attention is turning to smaller, varied buildings, which make up most of the UK’s stock. The FRAIMwork project is testing adaptable prefabricated facades installed by robots without scaffolding, at 25 per cent lower cost.

Circular Reno renovated 69 social homes with straw, timber and other bio-based panels from local supply chains, tested to the same fire standards as conventional products.

Questions from the room

Attendees explored why mixed tenure is less of an issue in Germany (far more people rent, and pepper potting puzzles European colleagues), the role of local banks in financing local projects, and why heritage homes have largely been avoided. An asset management contributor argued the UK cannot copy Germany’s timing of insulation with maintenance because the money is not set aside: assets are “sweated” until they break. Energiesprong UK and Healthy Homes Hub are also gathering interest in a European study tour next spring.

Health co-benefits

Warm rent neutrality protects residents from paying more for a healthier home, while external shutters fitted with insulation can cut indoor summer temperatures by five to six degrees, helping tackle overheating as well as cold.

Questions for housing providers to reflect on

1. Do your planned maintenance and retrofit programmes talk to each other, so insulation can be added when facades are already due for work?

2. Are you judging retrofit on tenants’ total housing cost, and could you commit that it will not rise?

3. Are you ready for tenant requests for balcony solar?

Key takeaways

1. Consistency beats generosity. Rules based, continuous funding lets landlords and suppliers plan years ahead.

2. Time retrofit with maintenance. Insulating when a facade needs work anyway roughly halves the extra cost.

[1]Serial retrofit: retrofitting many similar homes using standardised, often factory made components, to cut cost and time through scale.

[2]KfW: Germany’s state owned development bank, which provides low interest loans for energy efficient renovation.

Retrofit Society 2:0 , October 2026, panel write up

Image credit: Healthy Homes Hub