Here are some more answers from EST to clear up a couple of follow-up questions:
1. Is this only available to houses not connected to the gas grid (I know solar is excepted). There is some ambiguity of wording where “gas used as main fuel” is mentioned. What happens where gas is only a backup fuel (gas fire in lounge) and where oil is used for central heating?
You can still claim RHPP. As mains gas is not the primary heating fuel they will be displacing.
2. Does RHPP apply to existing houses or can it apply to new build as well?
Only householders occupying a house can apply for a voucher. So, for example where a householder applies for a voucher in respect of a main heating system in their newly completed house, or in the case of individual self-build at point of completion, this is eligible. However, neither householders applying in relation to an offplan development, nor installers or building developers in any case are in a position to apply – they would not be eligible.
3. Can owners who have installed systems since 15th July 2009 apply for vouchers, or does that date only apply to the RHI proper? What is the earliest start date for a RHPP eligible installation?
Installations made from 21st July 2011, but before the application for the voucher will be eligible. However, if you as a householder do commission or carry out an installation before receiving a voucher, it is at your own risk; and we can give no guarantee that you will receive a voucher. The Government or Energy Saving Trust will not be liable for any costs in relation to decisions you have taken on this basis. You may find as a result that you have committed to paying the full cost of the installation yourself. We would in general recommend not entering into any binding contractual commitment or otherwise pay out any money (including any deposit) for a renewable heating system before receiving a voucher.