Gwresogi, an installer based in Gwynedd in north west Wales, achieved MCS certification in April 2025 for solar PV, air source heat pumps and battery storage systems1. The certification is reported in an MCS case study on the company, published on 5 February 20261. MCS describes Gwresogi as one of 400 MCS certified contractors working in Wales, and states that more than one in ten Welsh households now has an MCS installation1.
The company was founded in 2014 and its team has a background in plumbing and heating1. Robert Williams, its managing director, said the motivation for certification was to demonstrate a commitment to standards in its local area1:
"We've always held the firm belief that customers deserve quality workmanship and systems. Our motivation for achieving MCS certification was to show our local community that we are committed to high standards."
MCS states that certification allows an installer's customers to access government schemes such as the Boiler Upgrade Scheme, where installations must be MCS certified, and that MCS is now the sole certification scheme for government clean heat measures1. Williams said certification was "fundamental to our business, allowing our customers to access government schemes and giving them the confidence that their installations meet industry-recognised standards"1.
The case study also describes a completed project: a three-day installation at a three-bedroom bungalow in Pwllheli, combining solar panels and an air source heat pump1. The work integrated the new system with existing underfloor heating in the kitchen and added radiators elsewhere in the property, reusing a significant proportion of the original system1. No installed capacity, system cost or performance figures for that project are given in the sources1.
Why it matters for households
MCS certification is the route by which a household installation can qualify for government support. MCS states that the Boiler Upgrade Scheme requires MCS certified installation, and that MCS is now the sole certification scheme for government clean heat measures1. For a household weighing up a heat pump, solar panels or a battery, the certification status of the installer is therefore tied to whether grant funding is available at all, not only to workmanship.
The certification covers three measures that interact in a single home: generation from solar PV, heating from an air source heat pump, and storage in a battery. A household considering more than one of these can check what a given certification actually covers, and how to verify it, through the site's guide to MCS certified installers. The individual technologies are set out in the guides to air source heat pumps and to solar PV, with the storage side covered in adding battery storage to a solar system.
The Pwllheli project illustrates a point that affects running costs rather than eligibility: retaining part of an existing heating system, in that case underfloor heating, alongside new radiators1. How much of an existing system can be reused is a property-specific question, and the sources give no figures on the savings or efficiency achieved in that home1.
What happens next
No next steps are reported for Gwresogi beyond the certification and the completed project1. MCS states that Wales is the best-performing UK nation for uptake of renewable technologies as a proportion of households1.
Sources2 cited
- Gwresogi: Meet the Installers Driving Wales’ Green Revolution - MCS, mcscertified.com
- Meet the Installers Driving Wales’ Green Revolution - MCS, mcscertified.com