The thermomodernization bonus is a form of state help for an investor who carries out thermomodernization enterprise. It is paid out by Bank Gospodarstwa Krajowego at 25% of the loan used for such an enterprise. An investor who carries out a thermomodernization enterprise only pays off 75% of the amount used for the loan. The thermomodaernization bonus only partakes to investors who benefit from a loan granted by banks co-operating with BGK, it cannot be used by enterprises that carry out thermomodernization enterprise with their own funds. The clients can be council, housing co-operatives, commercial law partnerships, housing associations, as well as natural persons, detached family house owners.