The rental contract as a rule specifies the monthly rent and what it covers (net rent plus additional expenses). If no additional expenses are spelled out, you can assume that these are included in the rent.
The rent may be increased effective on the next possible date of giving notice of termination. Excluded from this are rental contracts with a fixed duration. To increase the rent, the landlord must use a form approved by the canton. The tenant must be in receipt of it at least 10 days prior to the start of the notice period.
The increase must be clearly justified and explained in detail. As a rule, rents are based upon the reference interest rate, development of the cost of living (National Consumer Price Index) and the landlord's maintenance costs.
Reference interest rate
According to the ordinance concerning tenancy law modified on 1 January 2008, the reference interest rate applicable throughout Switzerland is decisive for establishing the monthly rent. It is determined on a quarterly basis and is published by the Federal Department of Economic Affairs.
Rent increases and maintenance costs
40 per cent of the increase in prices due to inflation as Based on the National Consumer Price Index may be used for a rent increase. On the other hand, according to the Federal Supreme Court, the landlord must clearly justify maintenance costs, explain them in detail and may not pass on these as a flat fee. Conclusion: As a tenant, you should accept only those rent increases which are clearly justified.
Rent increases following a renovation
The law allows a landlord to increase rents following a renovation that brings additional services and benefits. If only appliances are replaced, that does not justify a rent increase. However, if additional appliances are installed or if the kitchen, bathroom or even the complete apartment are totally renovated, the rent can be increased.
Contesting a rent increase
If tenants believe a rent increase is unjustified, they can contest it with the conciliation authorities within 30 days after receipt. If they miss this deadline, the increase can go into effect.