The announcement follows confirmation that the risk from certain pollutants discharged from such boilers is minimal.
The final domestic RHI policy, which was published in July 2013, said condensing biomass boilers would not be eligible for support, subject to tests carried out on behalf of the Department for the Environment, Food, and Rural Affairs (Defra).
The tests were to assess the potential impact on water quality of polycyclic aromatic hydrocarbons (PAHs) being emitted by these types of boilers.
PAHs are products of incomplete fuel burning and are categorised as potentially hazardous substances under the EU Water Framework Directive.
Defra has confirmed that, while a small amount of PAHs are released from the condensing biomass boilers, the levels released should not pose a significant threat to the aquatic environment once they have been through wastewater treatment.
The domestic RHI eligibility has been extended to condensing biomass boilers provided they meet the other eligibility criteria of the scheme, and it applies to boilers installed between 15 July 2009 and the launch of the scheme in spring 2014.