The Renewable Heat Incentive (RHI) for domestic customers has been hit by further delays.

The RHI is the government’s main subsidy to get homes and businesses to switch to renewable heating systems, but the Department of Energy and Climate Change (DECC)  now says that the domestic RHI will not launch until Spring 2014.

The industry argues that the tariffs have been too low to incentive businesses to take up the RHI. Figures just released by DECC shows that as of last month, there were just over 1000 non-domestic RHI systems accredited and eligible for payment and 76 per cent of those were for small solid biomass boilers (under 200 kilowatt). Just four per cent (43) were for small water or ground source heat pumps and one per cent (eight) were for large solid biomass boilers (over 1000 kW).

The non-domestic RHI is already up and running and the RHI for households, which has already been delayed once, was set to launch this summer. Instead, though, Ministers said only the "final details" of the scheme will be announced in summer 2013.

The delay was confirmed as ministers provided more details about which technologies would be in line for an increase in tariffs for the non-domestic RHI. Ground source heat pumps and large-scale biomass were both cited as in line for increases. The decision to increase tariffs follows an underspend of the non-domestic RHI Budget for 2012-13 and calls by industry to better support some technologies. Only around £24 million worth of RHI payments are expected to be paid out in this financial year out of a budget of £133 million.

Ministers are also consulting on expanding the RHI for business to include further technologies, such as air source heat pumps, and DECC said it would confirm the way forward in the summer.

"The Renewable Heat Incentive, which has been available for non domestic investors for over a year, is a key part of our approach to cutting carbon and driving forward the move to more sustainable low carbon heating alternatives," Energy and Climate Change Minister Greg Barker said.

"So far, over 1,000 groups have got on board, and today we have outlined details of our tariff review to help encourage even more organisations to invest."