The best explanation we've found is from the Centre for Sustainable Energy so click and read that if you hope to apply.

Meanwhile, here's what Ofgem say:.

What is it?

The Domestic Renewable Heat Incentive (Domestic RHI) is a government financial incentive to promote the use of renewable heat. Switching to heating systems that use naturally replenished energy can help the UK reduce its carbon emissions.

People who join the scheme and stick to its rules, receive quarterly payments for seven years for the amount of clean, green renewable heat their system produces.

Who's it for?

The scheme's open to anyone who can meet the joining requirements. It’s for households both off and on the gas grid. People off mains gas have the most potential to save on fuel bills and reduce carbon emissions.

The Domestic RHI

Key to joining is that the renewable heating system heats only a single property which is capable of getting a domestic Energy Performance Certificate (EPC). The EPC is the proof  that your property is assessed as a domestic ‘dwelling’. Without one, you won’t be able to apply and can’t join the scheme.

An EPC gives information about a property’s energy use, plus recommendations on how to reduce energy and save money. It’s required every time you buy, sell or rent a property. It’s included as part of a Green Deal Assessment, which is a requirement for most to join the Domestic RHI.

The Domestic Renewable Heat Incentive publication by the DECC can be downloaded from our Green Deal leaflets here.

The Non-Domestic RHI

Generally, if the renewable heating system is in commercial, public or industrial premises, then you would apply to the Non-Domestic RHI. This can include small and large businesses, hospitals, schools, and organisations with district heating schemes where one heating system serves multiple homes.

Where it’s more complicated

If your property set-up doesn’t quite fit into standard descriptions, or if your renewable system supplies heat to more than one building, it can be more difficult to decide which scheme to apply to. Or, if you’d be eligible to join either.

Ofgem assess it case by case, but very generally:

  • properties with a home office within a house that has, or can get a domestic EPC, should be eligible for the Domestic RHI.
  • properties with annexes attached to the house are normally covered by one domestic EPC and should be eligible for the Domestic RHI.
  • properties with a main house and a self-contained outbuilding (with its own bathroom and kitchen), both heated by a renewable heating system, would normally have an EPC for each. They would not be eligible for the Domestic RHI.
  • properties with a main house and other outbuildings all heated by a renewable heating system may not be eligible for the Domestic RHI.

 Find out more from Ofgem's website or see their publications:

See the Guardian article about the scheme.