Heat demand limits have been set for biomass, air source, and ground source heat pumps. There is no heat demand limit for solar thermal. Solar thermal payments continue to be based on the annual generation figure on the Microgeneration Certification Scheme (MCS)open key term pop-up Certificate.
The Government introduced changes to the Domestic RHI scheme Regulations on 20 September 2017. If you applied after the amendments to the regulations came into effect, annual heat demand limits will apply to you.
Heat demand limits cap the financial support that scheme participants can receive for their annual heat use. Heat demand limits have been introduced for air source heat pumps, ground source heat pumps, and biomass boilers and stoves - there is no heat demand limit for solar thermal.
Payments for heat pumps will continue to be made only on the renewable portion of the heat demand shown on your EPC. The electricity used by the heat pump to generate the renewable heat is deducted from the total heat generated to calculate the amount of renewable heat produced by the heat pump. This ratio of heat generated to electricity used is known as the Seasonal Performance Factor (SPF)open key term pop-up.
The figures for the heat demand limits are:
| Technology Type | Annual heat demand limit (kWh) |
| Air source heat pumps | 20,000 |
| Biomass boilers and stoves | 25,000 |
| Ground source heat pumps | 30,000 |
Please refer to our Factsheet: Tariffs and Payments and Payment calculations – heat demand limitopen key term pop-up for calculation examples.