It is an eligibility requirement for the domestic Renewable Heat Incentive Scheme, which supports the installation of domestic renewable heating systems, that both the product and installation are covered by the Microgeneration Certification Scheme (MCS), which is the nationally recognised quality assurance scheme for microgeneration renewable heating technologies. MCS standards require installations to a defined quality, using products that have met testing standards. For the installation to qualify for RHI, the installer must be a member of MCS, use a product that is certified by MCS and the product must be on the RHI Product Eligibility List: https://www.ofgem.gov.uk/publications-and-updates/domestic-renewable-heat-incentive-product-eligibility-list-pel
MCS and its certification bodies have a consumer protection process in place in case there is a problem with an installation. Installers also have to be members of a consumer code, either the Renewable Energy Consumer Code (RECC) or Home Insulation and Energy Systems Contractors Scheme (HIES). These are approved by the Chartered Trading Standards Institute (CTSI). The standards that installers must meet when contracting with consumers are set out by these codes. They also cover advertising and promotion, behaviour of sales staff, proposals, estimates and quotes, terms of business, cancellation rights, deposits and prepayments, guarantees, maintenance and service agreements and service and repair. Both RECC and HIES have accredited Alternative Dispute Resolution (ADR) procedures. The ADR processes for RECC and HIES can be found at: https://www.recc.org.uk/consumers/how-to-complain and https://www.hiesscheme.org.uk/how-to-complain/
New central heating systems can be installed under the Energy Company Obligation (ECO) with any system having to meet relevant building regulations, the publicly available specification (PAS) or other relevant requirements to be eligible. Further guidance can be found on the Ofgem website at: https://www.ofgem.gov.uk/publications-and-updates/energy-company-obligation-2017-18-eco2t-guidance-delivery
Government is supporting the implementation of the Each Home Counts review of quality and standards in the energy efficiency and renewable energy sector. This will involve the introduction of a new quality mark standard and Government has said that it intends to apply that to ECO.