Most of Europe’s buildings today will still be standing in 2050.
Keeping them in use and renovating them well usually causes less CO₂e than demolishing and building new.1
Of every 20 buildings standing in the EU today, 17 to 19 will still stand in 2050.
01 / Building new
Demolition makes more waste than everything else in Switzerland combined.
Taking down buildings, roads and railway lines produces about 17 million tonnes of material a year. All other waste in the country together comes to 6 to 16 million tonnes.
Making, transporting and disposing of the materials for Swiss buildings also causes 9 to 11 million tonnes of CO₂e a year, in Switzerland and abroad.
02 / What renovation keeps
Rebuilding causes more than twice the CO₂e of renovating.
For a typical Swiss apartment building of 1,000 m², demolishing and rebuilding causes about 400 tonnes more CO₂e from materials over 60 years than renovating it, within 210 to 600 tonnes. That is 2.3 times as much in the central case, and 1.5 to 4.3 times across the range.
03 / Heating
Even with 60 years of heating added, renovation stays ahead.
With the old heating replaced by a heat pump, as in both buildings here, the renovated building still causes about 290 tonnes less CO₂e over 60 years, heating included.
04 / Even against timber
Even against a timber new build, renovation saves material emissions.
If the new building has a timber structure, renovating still causes about 250 tonnes less CO₂e from materials over 60 years.
05 / People
In five years, one in a hundred people in the Zürich area had to leave their home.
From 2015 to 2020, 7,253 long-term tenants left buildings that were demolished, and 7,120 left for a total renovation. Renovating while residents stay, or adding storeys, keeps them in their homes.
06 / Homes
In 2025, Zürich demolished more than five times as many homes as stood empty.
The city lost 1,379 homes to demolition and gained 547 inside existing buildings, two thirds of them in former non-residential space. On June 1, 2026, 252 homes stood empty.
Across Switzerland 0.93 percent of homes stood empty that day. The office space advertised in 2024 could in theory hold 8,000 to 10,000 homes, though a consultancy study finds that hard in practice.
07 / Where we fit
Renovation starts with knowing what is already there.
Missing information about existing buildings is one of the reasons renovation is hard to plan, and across the EU only about one building in 500 gets a deep renovation each year.
Our robot scans the building as it stands, and our software turns the scan into point clouds, plans and models.
The plans and models describe the existing building, so a renovation can be planned against it.
We do not decide whether a building is kept. The emissions a renovation avoids are the owner’s, not ours.
The numbers on this page describe renovation in general. They are not savings made by Synoptic.
08 / How we calculated
One building type, Swiss values, every input stated.
- Question
- For a Swiss apartment building of 1,000 m², how much CO₂e from building materials do renovation and replacement cause over the next 60 years?
- Scope
- Grey emissions per SIA 2032: materials, construction, replacement of parts, disposal. The same floor area in both cases. Heating is compared separately.
- Inputs
- New build 10.5 to 12.2 kg CO₂e per m² and year, the current Swiss average. Renovation 3 to 7 kg, around the Swiss guide value of 5. Demolition of the old building 0 to 50 kg per m², once.4,6
- Result
- Renovation 180 to 420 t, replacement 630 to 780 t, difference 210 to 600 t, about 400 t in the central case.
- Heating
- Heat demand 21 kWh per m² and year for the new building and 60 for the renovated one, a heat pump in both with a seasonal performance factor of 3, the Swiss electricity mix at 0.128 kg CO₂e per kWh, held constant. Over 60 years that adds about 270 t to the renovation and 160 t to the new building.7,8
- Timber
- If the new building has a timber structure, it causes 2.5 kg CO₂e per m² and year less. The difference then falls to 60 to 450 t, about 250 t.9
- Limits
- One building type, Swiss values, guide values for renovation rather than measured averages, a constant electricity mix. Not every building can be renovated to a good standard, and replacements often add homes.
Renovate = area × renovation × years. Rebuild = area × (new build × years + demolition). Ranges at the extremes: the lowest rebuild against the highest renovation, and the other way round.
09 / Sources
- 1
Schwartz, Raslan, Mumovic, The life cycle carbon footprint of refurbished and new buildings: a systematic review of case studies, Renewable and Sustainable Energy Reviews 81, 2018. discovery.ucl.ac.uk ›
- 2
European Commission, A Renovation Wave for Europe, COM(2020) 662, October 14, 2020. eur-lex.europa.eu ›
- 3
Federal Office for the Environment (BAFU), Rohstoffe, Abfall und Kreislaufwirtschaft: Das Wichtigste in Kürze, September 25, 2025. bafu.admin.ch ›
- 4
Swiss Federal Council, Bericht in Erfüllung des Postulates 20.4135 Schaffner, August 20, 2025. parlament.ch ›
- 5
Synoptic, Grey emissions of renovation and replacement, November 2026. Method on this page ›
- 6
SIA, SIA 390/1:2025 Klimapfad, 2025 (guide value for conversions, the renovation input). shop.sia.ch ›
- 7
Intep for the City of Lucerne, Gebietsentwicklung Kleinmatt-/Bireggstrasse: Analyse Gesamtenergie, June 20, 2025 (heat demand values). stadtluzern.ch ›
- 8
treeze for BAFU, Umweltbilanz Strommix Schweiz 2018, 2018 (electricity mix). bafu.admin.ch ›
- 9
Machado, Silvestre, Bohne, Building and Environment, 2025 (structure in reinforced concrete and in timber).
- 10
Kauer, Lutz, Büttiker, Kaufmann; Federal Office for Housing (BWO) and ETH Zürich, Bautätigkeit und Verdrängung in der städtischen Schweiz, June 2025. bwo.admin.ch ›
- 11
Statistik Stadt Zürich, Mehr Wohnungen trotz vieler Abbrüche, February 2026 (2025 data). stadt-zuerich.ch ›
- 12
Statistik Stadt Zürich, Leichter Anstieg: 252 Leerwohnungen in Zürich, August 2026. stadt-zuerich.ch ›
- 13
Federal Statistical Office (BFS), Leerwohnungsziffer fällt unter 1 Prozent im Jahr 2026, September 10, 2026. admin.ch ›
- 14
Wüest Partner, reported by awp (moneycab), Umnutzungspotenzial von Büros ist begrenzt, April 10, 2025 (a press report of the study, a secondary source). moneycab.com ›
Planning a renovation?
We measure the building as it stands, so the renovation can be planned with what is there.