Swiss heating statistics have a heat problem of their own
The building register shows large cantonal differences. But almost half of the heating entries are more than eight years old – a risk for planning and climate policy.
Switzerland's heating statistics are meant to show how quickly the country is replacing oil and gas heating systems. Yet on this central climate question of all things, the data base is surprisingly old. In the energy monitoring of the federal building and housing register, 51 percent of recorded buildings are assigned to the gas and heating oil category. At the same time, 49.7 percent of the heating entries have not been updated for more than eight years.
That second figure changes how the first one is read. It does not mean that half of the entries are wrong. An old oil heating system may still be in operation. But it does mean that for a substantial part of the building stock, the federal government does not know from a current report whether a heat pump, district heating or another system has been installed in the meantime.
A register, not a live counter
The monitoring draws on the federal building and housing register. Municipalities and cantons feed in information from the census, building permits, on-site inspections and other sources. For the data status of March 2026, the BFS reports that 34.2 percent of heating entries are younger than four years, 16.1 percent are four to eight years old and 49.7 percent are older than eight years.
The register is therefore valuable, but it is not a nationwide live counter of heating replacement. New buildings are usually well documented because they go through a permit procedure. Whether a replacement in an existing house reaches the dataset quickly or slowly depends on the cantonal and municipal process.
Cantonal comparisons need a warning label
The BFS dashboard shows the data down to cantonal and municipal level. That resolution is politically attractive: it makes visible where fossil systems are frequently registered and where alternatives appear more widespread. But a ranking can blend two effects – the actual heating stock and the quality of updating.
A canton with many newly verified entries can appear to move faster on paper than a canton whose register still lists old systems. Conversely, an old entry is not automatically fossil: what matters is what was last reported. A comparison is therefore only sound if it shows not just the energy source but also how current the entry is and where the information comes from.
This limitation is not new. In earlier building and housing statistics, the BFS had already pointed out that changes to heating systems were not recorded systematically and that a realistic picture could not always be guaranteed. The current monitoring now makes the shortfall measurable.
Why the data gap can cost money
For homeowners, the register entry is initially administrative material. For the public sector, it is a planning basis. Municipalities have to estimate where electricity grids need to be reinforced for heat pumps, where district heating networks should be expanded, or where subsidy programmes should be targeted. If the stock and the pace of renewal are unclear, misinvestments threaten: grids that are too large in the wrong place, or too little capacity where many heating systems are converted at the same time.
The climate balance depends on it as well. Buildings cause direct CO₂ emissions mainly through oil and gas. If replacement systems appear in the register late, the transformation looks slower than it is. If retired fossil systems remain wrongly listed as active, cantonal progress is underestimated. If, conversely, decommissioned or supplementary systems are missing, the balance can be too optimistic.
The solution is organisational, not statistical
A better statistic does not require a new survey of all households. It would be more obvious to merge reports from permits, subsidy programmes, furnace inspections and building energy certificates more bindingly and automatically – with clear responsibilities and data protection rules. It would be particularly helpful to show the currency of the underlying entries on an equal footing with every published cantonal figure.
The 51 percent figure shows how large the fossil starting point still is. The 49.7 percent figure shows how cautiously progress has to be measured. For a heat transition worth billions, setting targets is not enough. Switzerland also needs to know promptly which heating system is actually running in which building.
51 percent is not 51 percent of households
The dashboard counts buildings with a recorded heating system. A single-family home and a large apartment block each appear as one building. The 51 percent share therefore cannot be used to derive directly either the share of affected households or energy consumption or CO₂ emissions. For climate policy, building data has to be linked with living space, consumption and emission factors. The register answers the question “what is being heated with”, but not on its own the question “how much is being emitted”.
