What is RHI

Renewable Heat Incentive

The Domestic Renewable Heat Incentive (RHI) is a Government funded financial incentive for households to switch to renewable heating systems. The aim of the scheme is to help the UK reduce its carbon emissions.

Applicants must have one of the following eligible types of renewable heating systems:

  • Biomass only boiler
  • Biomass pellet stoves with integrated boiler

To qualify, the make and model of the system must meet the specific technical requirements. A checklist of products will be available once the scheme launches.

The Domestic RHI is separate to the Non-Domestic RHI, and it is clear cut for most people which one applies. You can apply for the Domestic RHI if your renewable heating system only heats a single home for which you have a domestic energy performance certificate (EPC). The Non-Domestic RHI is for those who have renewable heating systems in commercial, industrial or public premises.

Tariff Name Eligible Technology Eligible Sizes Tariffs
Small Commercial Biomass Solid Biomass including solid biomass contained in waste Less than 200 kWth
Tier 1
Less than 200 kWth
Tier 2


Medium Commericial Biomass 200 kWth and above & less than 1MWth
Tier 1
200 kWth and above & less than 1MWth
Tier 2


Large Commercial Biomass 1MWth and above 2.03
Solid biomass CHP systems (commissioned on or after 4 December 2013) Solid biomass CHp systems all capacities 4.17

Pellet costs depend mainly on the size and method of delivery. If you have room for a large fuel store that will accept several tonnes of pellets at a time, delivered in bulk by tanker, you can keep the cost down to around £250 per tonne in most parts of the UK.

Logs can be cheaper than pellets, but costs depend on the wood suppliers in your local area, as they cost a lot to store and transport. If you have room to store more than a year’s worth of logs you can save money by buying unseasoned logs and letting them season for a year. Search for wood fuel suppliers in your area at Log Pile.


Biomass boilers and stoves should be kept clean and swept regularly to remove ash. Ash quantities are generally very low (less than one per cent of fuel volume), but you will still need to empty the ash bin of a wood burning stove or boiler. This is likely to be weekly and never more than once a day. A log fire requires ash removal before every use.

Some appliances, particularly boilers, have self-cleaning systems which will collect ash from the combustion grate and the heat exchanger tubes. If there is no automatic ash cleaning mechanism in place the boiler will need to be shut down periodically so that this can be done by hand. If the ash is not cleaned out regularly, it will build up and adversely affect combustion conditions, which can lead to boiler failure and shut down. Some boilers have a mechanism for compressing the ash which reduces the number of times the ash bin needs to be emptied.

With automatic ash removal and cleaning of the heat exchanger the only other maintenance requirement will be occasional ash removal and an annual maintenance check. If you have a wood burning stove or boiler the chimney and flue pipe must be swept regularly to remove all soot deposits and prevent blockage. HETAS recommend that this “should be done at least twice a year, preferably before the heating season to check that the flue has not been blocked by bird’s nests for example and also at the end of the heating season to prevent soot deposits from resting in the chimney during the dormant period”.

Contact us for more on the Renewable Heat Incentive

Please feel free to contact us on +44 (0) 28 8225 0160 or m: +44 (0) 77 9354 8036
e: info@alternativeenergy.ie for more information on the renewable heat incentive, alternatively you can send us an email or fill in our enquiry form.

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