It is important that you are aware of actual rent prices in the area regardless of whether you are looking for a new investment property or placing an ad for your existing rental apartment. There are various rental websites (e.g. vuokraovi.com and oikotie.fi) to help you with this. They are particularly useful if you are not yet familiar with the pricing in the area.
Most often, an appropriate rent is not the highest nor the lowest in the market. An appropriate rent provides a satisfactory rental profit and also helps with tenant commitment and execution of obligations. The risk of having the apartment empty and unused is minimized and the flux of tenants slows down. There are always costs and risks involved with tenant changes. High rental profit in the short term may become a risk in the long term.
Timing is also relevant. Cities with universities, polytechnics, and other schools are more expensive particularly during the high season, e.g. early fall when freshmen move to a new location and need an apartment. Families with children tend to move in the summer due to the fact that schools are on a break and the children do not need to change schools in the middle of the semester.
Data on actual rents in bigger cities is available at asuntojenvuokrat.fi, a service provided by the Ministry of the Environment and the Housing Finance and Development Centre of Finland. One way to figure out regional rent prices is to ask around, e.g. from other real estate investors or from friends who rent or even from real estate agents. In addition, there are rental statistics available on Statistics Finland’s pages.
The Finnish Landlord Association publishes a regular report on current and future markets in various cities. This report looks at trends in rent prices in different cities and in variably-sized apartments. Statistical data by Vuokraovi.com is used in the report. The market report is available in Finnish here.