Apartment buildings: up to five energy classes better, no investment costs

The problem: retrofitting costs money, doing nothing costs more

Apartment buildings in energy classes G and H are offered on average around 28 percent below comparable class A properties. Banks assess energy performance with every financing, the CO₂ price on gas and oil rises every year, and the Building Energy Act with municipal heat planning sets deadlines for fossil heating.

Retrofitting the boiler room yourself costs six figures, plus planning, subsidy applications and operation. Many owners postpone it. Meanwhile the building loses value.

The solution: buy heat instead of owning a heating system

With heat contracting a provider takes over the entire heat generation in the building. It converts the old boiler room, finances the technology and operates it over the contract term. You buy heat at the agreed price per kilowatt hour, fixed for 10 to 15 years, and pass it on to tenants as before.

Work takes place in the boiler room, on the building and on the roof. No scaffolding on the facade, no access to the apartments, operation continues.

What gets installed

Heat pumps replace boiler and burner. The storage tank goes into the basement, the outdoor units stand next to the building or on the roof.
Photovoltaics on the roof supply the electricity for operation where the building allows it.
Learning controls with sensors and valves on the existing pipe network balance the risers hydraulically and lower the flow temperature.
Tenants receive heat as before through the service charges. Switching to heat supply is regulated in section 556c of the German Civil Code.

The result: up to five energy classes better

Because primary energy demand drops drastically with heat pumps, the energy class on the certificate improves by up to five levels depending on the starting point, for example from G to B. That affects sale price, lending value and lettability.

Topic	Own retrofit	Heat supply
Conversion costs	Owner	Provider
Planning, financing, maintenance	Owner	Provider
Facade, scaffolding, apartments	usually required	not required
Heat price	fluctuates with the market	fixed for 10 to 15 years
Energy class	depends on scope	up to 5 classes better

Which buildings qualify

From 8 residential units. Apartment building, no upper limit. Several buildings of one owner are assessed together.
Central heating system. One system for the building. Individual gas boilers per flat do not qualify.
Energy class E or worse according to the certificate. For district heating we also look at better classes.
One owner for the whole building, or an owners' association with a resolution of the owners' meeting.
Heating costs run through the owner, who passes them on to tenants.

How it works

Submit the property. Address and key data, plus energy certificate and energy statements of the last three years. Takes two minutes.
Calculation. We check the key data and align the design with the provider. Feedback usually within 5 working days.
Offer and technical review. Written offer with a guaranteed heat price, site visit of boiler room, floor space and roof.
Contract. Heat supply contract between owner and provider, then scheduling of the installation during ongoing operation.

What it costs

Assessment, site visit and offer are free of charge and without obligation for owners. The provider bears the conversion costs. You pay the agreed heat price, fixed over the term. Kola NetZero is paid by the provider.

Frequently asked questions

Can I really retrofit my apartment building without my own money?

Yes, for the heat generation. The provider plans, finances, builds and operates the new boiler room. Facade, windows and insulation are not part of the model, but for the energy class the heating is the biggest lever.

How many energy classes are realistic?

Depending on the starting point up to five classes, for example from G to B. The exact figure is stated in the offer after calculation.

What changes for tenants?

Tenants receive heat as before and pay for it through the service charge statement. Under section 556c of the Civil Code the costs may not exceed the previous service charges. No access to the apartments is needed.

How long until I receive an offer?

After submission we usually check the key data within 5 working days. Then follows the site visit, after that the written offer.

What does the assessment cost?

Nothing. Assessment, site visit and offer are free of charge and without obligation. Kola NetZero is paid by the provider.