Every time an old oil or gas boiler gives out, the habit of replacing it with another fossil burner quietly locks in decades of emissions, and a group of Swiss cantons has set out to break that cycle. A new study in PLOS Climate, from researchers at the University of Geneva, examines how these regions have combined renewable mandates, subsidies and public information to steer households toward heat pumps, and finds the approach working better than most of Europe's more cautious efforts. Its authors stress that the evidence is still early, and that the outcome rests on something beyond any cant
Swiss Cantons Show How Targeted Policy Can Steer Building Heating Away From Fossil Boilers Toward Heat Pumps
Quasi-ban: no outright prohibition, yet fossil boilers are being replaced
Mark
Why does this study matter beyond Switzerland?
Mimi
Because the usual outcome is that a broken boiler gets replaced by the same kind of boiler. These cantons built policy around that moment.
Mark
What exactly did they do?
Mimi
Mandatory renewable shares, subsidies, and information campaigns, all together. The authors call the result a quasi-ban on fossil boilers.
Luke
Quasi is doing real work there. It isn't a full ban, and the paper says that's deliberate.
Mimi
Right. Leaving room for hard cases seems to make owners more accepting.
Luke
Seems is the key word. The evidence is interviews and the authors call it early. That's not measured installation data.
Mark
And the cost figure?
Mimi
With a subsidy of 11% of investment, a heat pump's levelised cost is 7% above a gas boiler.
Luke
That's one modelled scenario, and the paper says it swings with the gas-to-electricity price ratio. If that ratio falls, the picture changes.
Mark
Does Switzerland's clean electricity limit how far this travels?
Mimi
It helps the emissions case a lot. Other countries were compared, but results will differ with their grids.
Luke
And whether other governments will adopt this is unknown. Germany and the Netherlands have recently backed away from tougher rules.
The Pulse
- Old fossil boilers are being replaced by reflex, and Swiss cantons are working to interrupt that habit in older buildings.
- Cantonal packages of renewable mandates, subsidies and information campaigns amount to a quasi-ban on new fossil boilers, while stopping short of an outright prohibition.
- Across Europe, most countries have softened or delayed their heating rules, leaving Switzerland's approach comparatively bold and exposed.
- A typical subsidy of about 11% brings heat pumps within roughly 7% of gas boilers on lifetime cost, but the economics hinge on the gas-to-electricity price ratio.
- The authors recommend the model to other countries, and the next test is whether anyone adopts it while those price ratios stay favourable.
Every time an old oil or gas boiler gives out, the habit of replacing it with another fossil burner quietly locks in decades of emissions, and a group of Swiss cantons has set out to break that cycle. A new study in PLOS Climate, from researchers at the University of Geneva, examines how these regions have combined renewable mandates, subsidies and public information to steer households toward heat pumps, and finds the approach working better than most of Europe's more cautious efforts. Its authors stress that the evidence is still early, and that the outcome rests on something beyond any canton's control: the price relationship between gas and electricity. What Switzerland is testing, in effect, is whether a country can change the habits of the home furnace without forcing its owners into a corner.
When an old oil or gas boiler in an older building reaches the end of its life, the owner almost always buys another one. A group of Swiss cantons has decided to break that pattern, and a new PLOS Climate paper led by Martin Patel and colleagues at the University of Geneva examines how they have done it and whether it is working. The authors, drawing mainly on interviews with officials in the leading cantons, present their findings as early evidence rather than a final verdict.
The cantons did not rely on one tool. They combined a mandatory renewable share when a heating system is replaced, subsidies for the switch, and information campaigns. Together these form what the authors call a quasi-ban on fossil boilers, with heat pumps taking their place. The qualifier matters: by avoiding an outright ban, the cantons appear to have won more acceptance from owners and kept room for the hardest cases where no fully renewable option works technically or financially.
Set against the rest of Europe, the Swiss approach stands out. The EU aims for a decarbonised building stock by 2050, but most member states have been cautious, and several recent governments, including in Germany and the Netherlands, have softened or reversed earlier rules. Switzerland's own electricity, which is very low in carbon, gives heat pumps an especially strong climate case, though the authors caution that this only holds if renewable power is available in winter, possibly through seasonal storage, and that insulation should ideally come first.
On cost, a subsidy around 11% of the investment leaves a heat pump's lifetime cost about 7% above a gas boiler, which the authors consider acceptable. Yet that balance is fragile, since viability depends heavily on gas prices relative to electricity prices. The authors conclude the cantonal measures are effective, affordable and accepted, and they recommend them elsewhere. Whether other countries follow, and whether the price landscape cooperates, will determine whether Switzerland's experiment becomes a model or remains a local success.
When an oil or gas boiler in an older building reaches the end of its life, the owner usually buys another oil or gas boiler. That habit is the problem a group of Swiss cantons set out to break, and a new paper in PLOS Climate, published April 1, 2026, looks at how they have gone about it and whether it is working.
The study, led by Martin Patel and colleagues at the University of Geneva, rests mainly on semi-structured interviews about the policies in the leading cantons. The authors describe their findings as early evidence, not a final verdict. The research was funded by the Chair for Energy Efficiency at the University of Geneva and by two projects backed by the Swiss Federal Office of Energy, DeCarbCH and RenewHeat. The Cantonal Office of Energy in Geneva also contributed to RenewHeat. The authors state that the funders had no role in the study's design or publication.
The cantons did not rely on a single instrument. Their packages combine a mandatory share of renewable energy when a heating system is replaced, subsidies for the switch, and information and communication measures. Together, the authors say, these amount to a quasi-ban on fossil fuel boilers, with heat pumps the main technology taking their place. The word quasi matters. The cantons avoided outright bans. According to the paper, that seems to raise acceptance among building owners, and it leaves room for the hardest replacement cases, where no fully renewable option is technically or financially viable.
The paper places this against a patchy European record. The EU wants its whole building stock decarbonised by 2050 and requires new buildings to be zero-emission from 2030. Its buildings directive calls for a clear legal basis for banning fossil fuel boilers but gives no guidance on how. Denmark makes renewable heating the default, with exceptions such as areas served by a gas grid. Belgium, France, Greece and Slovenia focus on phasing out heating oil. Austria, Belgium, Ireland and Slovenia bar fossil fuels in new buildings, and Austria has set distant decommissioning deadlines of 2035 to 2040. Germany adopted a 65% renewable share for newly installed heating in existing buildings, taking effect in mid 2026 or mid 2028 depending on municipality size, but its new government has announced it will revise the law. The Netherlands' de facto ban on pure gas boilers from 2026 was cancelled by its new government. No EU country currently prescribes full decarbonisation of heating in existing buildings in the short term, and the authors say even Germany's targets were far less ambitious than Switzerland's.
Switzerland's case for heat pumps is strengthened by its electricity. The authors compared the CO2 emissions of heat pumps against gas and oil boilers across several European countries, and the very low carbon footprint of Swiss power makes the comparison especially favourable. They add a caveat: a heat pump only counts as a convincing solution if renewable electricity is available whenever it runs, including winter, which may require seasonal storage such as power-to-gas. They also say building insulation should ideally come first, to avoid high winter electricity demand.
On cost, the study compared the levelised cost of heat pumps at different subsidy levels. With a typical subsidy equal to 11% of the investment cost, a heat pump's levelised cost comes out 7% above that of a gas boiler, which the authors judge acceptable. A sensitivity analysis shows that financial viability depends heavily on a high ratio of gas prices to electricity prices.
The authors conclude that the cantonal measures are effective, affordable and accepted, and recommend them to other countries. What to watch is whether those countries, several of which have recently softened their own rules, adopt a similar mix, and whether gas and electricity prices keep the economics favourable.
Notable Quotes
Evidence from leading cantons indicates the policy measures are effective, affordable and accepted and can be recommended to other countries.— Patel et al., PLOS Climate (2026)
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