BERN. In the basement of a 1960s apartment block in Ostermundigen, the oil burner that rumbled for half a century has been replaced by a machine the size of a wardrobe that hums, discreetly, against the wall. Multiplied by tens of thousands of basements, that quiet swap explains a statistic that would have seemed fanciful five years ago.
Figures compiled by the industry's specialist association show that annual heat pump installations have doubled within three years, from roughly 22,000 units to more than 45,000 last year. The curve began climbing when oil prices spiked in 2022 and has not flattened since. Switzerland, long the European champion of the technology per capita, has found a new gear.
The machines themselves have matured. Four out of five units sold are air-to-water systems drawing warmth from the outdoor air even at minus seven degrees, and modern equipment delivers three to four kilowatt hours of heat for every kilowatt hour of electricity it consumes. Larger buildings increasingly use borehole probes sunk a hundred metres or more into the ground.
The policy engine is cantonal. Under the model energy prescriptions adopted by a growing number of cantons, a fossil boiler that reaches the end of its service life must be replaced by a renewable system, and subsidy programmes, financed in part by the CO2 levy on heating fuels, offer households grants that commonly run from 4,000 to 12,000 francs. Several cantons add top-up grants for low-income households, and a few municipalities layer their own bonuses on top.
Local politics decides the details, and the details are fought over. Municipal assemblies weigh district heating networks against individual pumps; heritage officers dispute the placing of outdoor units on protected facades; landlords and tenants argue, within the limits of tenancy law, over how much of the cost may flow into rents.
The economics have tipped. A conversion in a single-family house costs between 25,000 and 40,000 francs installed, but with oil prices where they have been, payback periods of eight to fourteen years are common, and new tariffs let heat pumps run cheaply at hours when the grid has power to spare. Financing packages from banks and cantonal lenders, some tied to the energy certificate of the building, have removed much of the cash-flow problem.
The constraint is human. The sector estimates it needs well over a thousand additional heating engineers, vocational schools have expanded their courses, and in some cantons households still wait months for an installation slot. The waiting list, installers say, is now the strongest argument for ordering early. Manufacturers have responded by expanding Swiss assembly lines and by shipping larger units suited to apartment blocks, the segment with the most headroom.
“The bottleneck is no longer the technology, it is the diary of the installer,” said a spokesperson for the heat pump industry association. The training pipeline, the association adds, is the number it watches most closely.
The environmental stakes are direct. Buildings account for roughly a quarter of Swiss greenhouse gas emissions, most of it from oil and gas boilers, and every conversion removes a few tonnes of carbon dioxide a year. The flip side is demand: widespread electrification of heating will add several terawatt hours of winter consumption by 2035, a projection that keeps grid planners busy.
The next decisions are already scheduled. Cantonal subsidy rules are to be harmonised further, new noise limits for outdoor units take effect shortly, and the installation statistics will be published each spring so that the trend, or its faltering, is visible to all.
The contrast with the neighbourhood is instructive. Germany's heated political battle over its building energy law showed how quickly heating policy can turn toxic; Switzerland's cantonal incrementalism, slower on paper, has so far proved the more durable route. Across the Alps, Austria's own boiler phase-out follows a similar regional logic, and the two countries' installers now compete for the same components.
The sound of the transition, in the end, is not a bang but a hum. It is coming from the basement.