Energetisch saniertes Haus im Mittagslicht mit frisch gedämmter heller Fassade und Wärmepumpe an der Hausseite

Energy retrofit

Detached house in Greater Munich, built 1972 – retrofit with a heat pump

Location: Greater Munich
Year built: 1972
Scope: Insulation, basement ceiling, heat pump
Duration: Around nine months in stages

Example project – will be replaced by a documented client project.

Starting point

Off oil before the boiler decides

A detached house from 1972, around 150 m² of living space, with an oil boiler from 1994 that had lately needed a repair every year. The owners wanted to decide the switch to a heat pump themselves – not have the boiler decide it on a January morning. The walls were uninsulated; the windows from 2005, by contrast, were in serviceable condition.

Brief

Envelope and heating from a single source

We surveyed the building envelope and the heating plant together, set the sequence and executed both: insulation of the facade and basement ceiling, then the replacement of the heat generator including hydraulic balancing. The funding application was not ours – the owners' energy consultant submitted it, and we supplied the technical documentation.

Bausachverständiger mit Klemmbrett prüft Rohrleitungen und Manometer einer bestehenden Heizungsanlage im hellen Keller — Envelope and plant in one appointment. Both were surveyed together – a house's heat load cannot be calculated without its walls.

Decisions

Insulate first, then calculate, then buy

There were two possible routes: install the heat pump straight away, sized for the uninsulated house – or insulate the envelope first and recalculate the heat load afterwards. We advised the second: after insulation, the heat load came out around a third below the first estimate, and the system could be one size smaller. The radiators were checked against the lower flow temperature – most stayed, two were swapped for larger ones. The position of the outdoor unit was also fixed before ordering, with noise and the boundary distance in mind – not afterwards.

Eingerüstetes Haus unter hellem Mittagshimmel, Dämmplatten im präzisen Raster halb aufgebracht, davor ebener heller Vorplatz — The insulation came first. Only with the envelope finished was it clear how much heat the house really needs – and how small the heat pump could be.

Execution

Two stages in nine months

In summer, the envelope: scaffolding, 16 centimetres of facade insulation with insulated reveals, and below it the basement ceiling. In autumn, the plant: heat pump, buffer cylinder, new pipework in the basement and hydraulic balancing across every room. The house remained occupied throughout; water and heating were off on two days – announced a week in advance.

Mineralwolldämmung fugenlos an den Holzrahmen des Fensters gepresst, klares Tageslicht auf der Fuge — Meeting the windows of 2005. The existing windows stayed – the reveals were insulated too, so that no cold edge forms at the frame.

Outcome

A smaller purchase, quieter heating – and a wait

The heat pump runs at a low flow temperature without a single radiator having become too small – that was the point of the sequence. What was difficult was the waiting: the grid operator's approval for the connection took six weeks, and precisely for that reason the old boiler stayed in the basement until commissioning. On top of that came an item nobody had on the list beforehand: the meter cabinet from 1972 had to be replaced before the grid operator would agree.

Handwerker dokumentiert eine freigelegte Wand mit dem Tablet, grüne Laserlinie über dem Mauerwerk, Tageslicht aus der Fensteröffnung — Documented before it is closed up. Pipe runs and wall build-ups were photographed before closing – nobody has to guess at the next project.

Year built: 1972
Carried out: 2024, two stages
Trades: Facade & Insulation, basement ceiling, Heating
Scope: Envelope and heat generator, around 150 m² of living space
Heating: Air-to-water heat pump, hydraulically balanced

Let’s talk about your project.

The initial consultation is no-obligation. If we are not the right partner for your project, we will tell you so.

Daniel Braun

Your point of contact

When you call or write, he is the one you reach. He takes down what needs doing and gets back to you – even if the answer is that we are not the right firm for the job.

What happens after your enquiry

A reply within 24 hours on working days.
A short phone call – is the project a good fit for us?
An on-site visit with a building survey.