The Greener Homes Scheme provides grants to homeowners who intend to purchase a new renewable energy heating system. Originally the sheme covered both new and existing housing, but is now restricted to existing housing with new measures dealing with new housing under building regulations. The scheme is administered by Sustainable Energy Ireland (SEI) and aims to increase the use of renewable energy and sustainable energy technologies in Irish homes. Grants are provided to householders who invest in renewable energy based heating systems under the following categories: -Solar Thermal Space and or Hot water heating -Heat Pump (horizontal and vertical ground collectors, water to water and air source) -Wood chip or pellet stoves and boilers -Biomass / Wood pellet Stove with integral boiler Grants have been disbursed since 1 October 2007, and as of May 2008 there were 20,500 scheme applications. 26% were for heat pump technologies, 27% for biomass, and 47% for solar.