Who is entitled to a rent reduction in Switzerland?
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All tenants in Switzerland whose lease is based on a reference interest rate higher than the current one. The decisive factor is the reference rate stated in the contract at the time of signing. If it exceeds today's rate (currently 1.25%, as of September 2025), a legal entitlement exists under Art. 270a CO — without the landlord's consent.
What is the Swiss reference interest rate (Referenzzinssatz)?
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The reference interest rate is a figure set quarterly by the Federal Office for Housing (FOH), based on the average of outstanding Swiss mortgages. It serves as the anchor for rent adjustments: when it drops, tenants can demand a reduction; when it rises, landlords may increase rent.
How is the rent reduction calculated?
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Three steps: (1) Difference: reference rate at contract signing minus current reference rate. (2) Steps: every 0.25% reduction equals one step. (3) Reduction: each step entitles you to reduce net rent by 2.91%. Example: contract rate 1.75%, current 1.25% → 2 steps → 5.82% reduction of net rent.
Does my landlord have to agree to the rent reduction?
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No. The entitlement exists by law (Art. 270a CO) on first written request. The landlord is obliged to reduce the rent unless they can prove that their costs (e.g. maintenance, mortgage interest) have risen by the same amount.
When does the rent reduction take effect?
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The reduction applies from the first day of the month following the landlord's receipt of the request. Important: the request must be in writing and you should be able to prove delivery — ideally by registered mail. The reduction does not apply retroactively.
What is the difference between net rent and gross rent?
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Net rent (Nettomietzins) is the pure rent without utilities (heating, hot water, maintenance, etc.). Gross rent (Bruttomietzins) includes net rent plus utilities advance payment. Rent reductions always refer to net rent. Both figures are usually listed separately in the lease.
What if my landlord refuses the rent reduction?
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If the landlord refuses or doesn't respond, you can contact the cantonal rent conciliation authority (Schlichtungsbehörde für Mietangelegenheiten) free of charge. They mediate between landlord and tenant. Only after conciliation can a judge decide. The process is free of court fees.
Do I need a lawyer for the rent reduction?
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No. The process is clearly defined by law and no lawyer is required. A correct reduction letter is sufficient. Legal advice may be helpful if the landlord refuses and the case goes to conciliation — but it is not required even there.
What does Zinssenker.ch cost?
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Checking your entitlement is completely free. The finished reduction letter as a PDF download is also free. For CHF 9.90 you can have the letter printed and sent by post to your landlord — convenient, without needing to visit the post office yourself.
Does the rent reduction also apply to commercial premises?
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Swiss tenancy law (Art. 270a CO) generally applies to commercial premises too. However, commercial leases may contain contractual exceptions. Check your lease for such clauses. If in doubt, consult the Swiss Tenants' Association (Mieterverband) or a lawyer.