Information of the scope of housing supplement you will find from the student financial aid brochure from KELA's (The Social Insurance Institution of Finland) home page.
General housing allowance after 1.8.2017
The housing costs of higher education students in Finland are currently mainly subsidized through the student housing supplement, but from 1.8.2017 onwards students will be covered by the general housing allowance scheme. Kela will cease student housing supplement payments automatically. Remember to apply for general housing allowance instead! You can apply for the allowance from Kela.
Low-income households are eligible for general housing allowance from Kela to help with their housing costs. A household includes everyone sharing living quarters, and the housing allowance is granted to the household collectively.