To complement the SDE+ with a scheme for smaller renewable energy systems, the investment subsidy scheme ISDE has started in 2016. This scheme was based on one of the agreements under the Agreement on Energy for Sustainable Growth form 2013. The scheme is planned for the period 2016-2020. Households and small commercial users can receive an allowance for the purchase of heat pumps, biomass boilers, solar water heaters, pellet stoves and small wood-fired boilers.
In 2016 and 2017 the budget was € 70 million/year; in 2018 and 2019 the budget is €100 million/year.