Germany has roughly 14 million poorly insulated homes, a federal subsidy that covers a large share of the bill, and broad public agreement that the country should fix its leaky housing stock. What it does not have is enough people willing to do the work. That gap, between a problem nearly everyone wants solved and a workforce far too small to solve it, is the opening VARM has built a company around, and last week the Berlin startup raised €17.5 million to close it.

The Series A was led by ABN AMRO Sustainable Impact Fund, a €500 million vehicle backed by the Dutch bank, and co-led by GET Fund, the Munich firm once known as Munich Venture Partners. Aurum Impact, the investing arm of the Goldbeck family office, joined as a new backer, alongside returning investors Emerge, Pale Blue Dot, and noa. It is a cap table with real cleantech mileage on it: GET Fund’s earlier exits include sonnen, the home-battery company Shell bought, and Luxexcel, a lens maker Meta acquired. The money brings VARM’s total raised past €24 million, and most of the new tranche goes into one place, expanding the installer network behind the product rather than the product itself.

Demand was never the thing standing in the way

The usual account of why Europe cannot decarbonise its buildings fast enough blames money, technology, or political will. VARM’s pitch begins by throwing all three out. The insulation itself is a solved, decades-old product. The subsidies exist: after grants from Germany’s federal economics agency, BAFA, a homeowner pays under €4,000 out of pocket on a job that lists at around €5,000, cuts heating bills by up to 50%, and pays for itself within four to seven years. The demand is there too, with hundreds of German households signing up every month.

What is missing is the installer. The German trades market for retrofits is fragmented and short-staffed, and the existing middlemen make it worse. Energy-consulting portals broker jobs and then hand them off. General contractors coordinate subcontractors without ever building their own capacity to do the work. “In the retrofit market, demand is not the problem, execution is,” said Gaetano Giuffré of ABN AMRO Sustainable Impact Fund. Brokerage models, in his telling, only shuffle the shortage around. They do not remove it.

A logistics company wearing a climatetech badge

VARM’s answer is to stop fighting over the scarce pool of certified specialists and manufacture its own. Through a model it calls the Cloud Installer, it trains career changers, people coming out of logistics, retail, and adjacent trades, into certified insulation installers in a matter of weeks. Established trade firms then join its partner network, add insulation to what they already sell, and run the jobs on VARM’s software. The platform owns the unglamorous middle of every project: automated measurement capture, material-quantity calculation, fixed-price quoting, subsidy paperwork, scheduling, and in-field quality checks. A standard single-family home gets done in a single day, often in about six hours.

There is a labour-market bet folded inside the climate one. By opening insulation work to people without a traditional trade background, VARM is trying to widen the installer pipeline at the same time as it widens its own revenue, turning a skills shortage into a hiring funnel. The founders have built unglamorous operations before. Christian Grüner, the CEO, is a mathematician who spent time at Siemens Advanta and earlier ran a longevity-supplement business. Sebastian Würz, his co-founder, scaled the co-living platform homefully to a Series B before it was acquired by Habyt in 2021. Their wager, since starting VARM in 2023, is that the binding constraint on the heat transition is operational rather than scientific, and that whoever industrialises the labour takes the market.

The catch is that a franchise is only as good as its worst crew

So far the receipts hold. VARM operates in seven German cities, Berlin, Hamburg, Bremen, Essen, Cologne, Frankfurt, and Minden, has completed thousands of projects since 2023, and carries a 4.9-star Google rating across hundreds of reviews. It is B Corp certified. GET Fund’s Julian Klaiber said the deciding signal was that quality stayed “consistently stable, scalable, and verifiable” as volume grew, which is the polite way of saying this is exactly the point where the model usually breaks.

Because it does. A decentralised, franchise-style network is only as good as the least careful crew on a job in a city the head office has never visited. Insulation done badly does not announce itself on day one. It shows up years later as trapped moisture and mould behind a wall, long after the fixed-price invoice was paid. The entire model rests on the AI platform enforcing one standard across hundreds of semi-independent installers, and that is a promise far easier to print in a release than to keep across a continent.

The market pulling VARM forward is real and getting more urgent. The EU’s revised Energy Performance of Buildings Directive, in force since May 2024, requires member states to renovate their worst-performing buildings on a fixed timetable, with roughly 75% of the bloc’s stock rated energy-inefficient and deep-renovation rates stuck near 1% a year. Berlin has quietly become a cluster for the problem: ecoworks raised €23 million for serial building renovation, GALVANY €10 million for heat pumps in apartment blocks, and metiundo €40 million for building-energy metering. VARM’s nearest comparable, the heat-pump installer thermondo, raised more than $56 million before Brookfield acquired it. Against all of them VARM is making the narrower bet, that insulation, the cheapest lever, has been overlooked in favour of flashier machinery.

Whether that bet becomes the retrofit infrastructure Europe keeps saying it needs comes down to one unromantic question: can a company built around one-day insulation jobs hold its quality steady as it goes from seven German cities to a continent. The capital to try is now in the bank. The 14 million cold houses are still waiting.