Relevant parts

The Domestic RHI scheme is intended to support the installation of new equipment.

To be eligible for the Domestic RHI scheme, all heat generating parts of the heating system must be new (ie. must not have been used before the heating system’s first commissioning date). We refer to the heat generating equipment of the heating system as "relevant parts". See Refurbished equipmentopen key term pop-up.

There are, however, some previously used relevant parts which are permissible under the Domestic RHI scheme. The following table shows a list of relevant parts that can and cannot have been previously used at the time of first commissioning.

Heating system type	Cannot have been used before first commissioning date of heating system	Can have been used before first commissioning date of the heating system	Can have been used before first commissioning date of the heating system
	(relevant parts which are not excepted components)	(not heat generating components - ie. not relevant parts)	(relevant parts which are excepted components)
Biomass boiler	Boiler	Fuel storage/preparation/delivery equipment Fixings Controls Emitters (e.g. radiators) Hot water cylinders Pipes Circulation pumps Supplementary electric heaters Buffer tanks/ thermal stores Expansion vessels	Immersion heaters for domestic hot water Supplementary electric heaters Circulation pumps
Biomass stove	Stove Heat exchanger Integrated back boiler	Fuel storage/preparation/delivery equipment. Pipes Fixings Controls Emitters Hot water cylinders Supplementary electric heaters Buffer tanks/ thermal stores Expansion vessels	Immersion heaters for domestic hot water Supplementary electric heaters Circulation pumps
Ground (or water) source heat pump	Ground or water loop Heat pump unit/ Compressor Internal oil/gas burner (hybrid heat pump systems)	Container and fixings Pipes Circulation pumps Emitters Hot water cylinders Supplementary electric heaters Buffer tanks/ thermal stores Expansion vessels Controls	Immersion heaters for domestic hot water Supplementary electric heaters Circulation pumps
Air Source Heat Pump	Heat pump unit/ Compressor Internal oil/gas burner (hybrid heat pump systems)	Container and fixings Pipes Supplementary electric heaters Controls Emitters Hot water cylinders Buffer tanks/ thermal stores Expansion vessels	Immersion heaters for domestic hot water Supplementary electric heaters Circulation pumps
Solar Thermal	Solar Collectors (flat plate or evacuated tubes)*	Roof fixings Pipes Supplementary electric heaters Controls Hot water cylinders Thermal store/buffer	Immersion heaters for domestic hot water Supplementary electric heaters Circulation pumps

*Evacuated tube cassettes / manifolds are part of the plant see refurbished equipment

Refurbished equipment

No part of a renewable heating system that generates heat may have been used before the date that it is first commissioned. This means that refurbished generating equipment (the equipment used to generate heat) isn’t eligible for the scheme. More.