The MCS Installer Scheme is changing – what does it mean for Retrofit Coordinators?

There’s a lot changing in retrofit at the moment, and the redevelopment of the MCS Installer Scheme is another development worth paying attention to.

Much of the conversation so far has understandably focused on installers. They’re the ones transitioning to the new scheme, getting to grips with MCS:2025 and understanding what the new requirements mean for their businesses. But we think there’s another conversation worth having. What does all of this mean for Retrofit Coordinators? When an MCS-certified technology forms part of a PAS 2035 project, it doesn’t exist in isolation. It sits within a wider retrofit design, alongside other measures, evidence, contractors and, ultimately, the outcomes we’re trying to achieve for the resident. That makes the changes relevant to more than just installers.

MCS Installer Scheme is changing, but the bigger picture hasn't

How do we know that what has been designed and installed is right for that particular home?

Certification is an important part of that assurance. But certification and coordination aren't the same thing.

A heat pump can be installed by a suitably certified installer, for example, but the Retrofit Coordinator still needs to consider how that measure interacts with the rest of the property. What is the condition of the building fabric? What does the heat-loss assessment tell us? Is the ventilation strategy appropriate? What other measures are planned? And, crucially, does the overall solution work for the person actually living there? That whole-house perspective doesn't disappear because an individual measure has its own certification framework. If anything, as assurance frameworks become more detailed, the need to connect everything together becomes more important.

The bigger question could be about evidence and competence

This is one area we'll be watching particularly closely as the new MCS scheme becomes established. Retrofit Coordinators already deal with a significant amount of project information. Assessments, designs, specifications, calculations, installation evidence, compliance documentation and handover information all need to tell a consistent story about what has happened to a property. MCS brings its own processes, calculations and evidence into that picture. But there’s an important distinction here. Having a calculation or document in place isn't necessarily the same as having confidence in the competence behind it. As software and systems become more accessible, there is a wider question for the sector about who is producing technical information and what qualifies them to do so.

A professional may hold a recognised construction qualification, for example, while having relatively little specialist knowledge of a particular MCS technology or requirement. For the Retrofit Coordinator, simply confirming that a calculation exists therefore can't always be the end of the conversation.

Who sits behind the evidence matters too

The Coordinator needs confidence not only that the appropriate evidence has been produced, but that it has been produced by someone with the appropriate competence for that particular element of the project. That might mean asking who completed the calculation, what their competence is in that area and whether the information itself makes sense within the wider retrofit design.

It sounds like a small distinction, but on large-scale programmes it could become an important one. The risk is that assurance becomes focused on whether the right documents are present rather than whether the decisions behind those documents are sound. And those are two very different things.

How will MCS Installer Scheme evidence fit into the PAS 2035 evidence trail?

There is another practical question here. How easily will the information generated through MCS fit into the wider PAS 2035 evidence trail? Ideally, better data and clearer accountability should make assurance easier. But only if the right people can access the right information at the right point in the project. A Retrofit Coordinator needs to understand what has happened across the property, not simply whether individual parts of the project have passed through their respective processes. That means information needs to move effectively between installers, designers, Coordinators and clients. Otherwise, we risk creating more information without necessarily creating more visibility. For organisations delivering retrofit across hundreds or thousands of homes, that distinction matters.

Retrofit Coordinators may need to ask slightly different questions

During the transition, Retrofit Coordinators are also likely to work with installers at different stages of moving onto the redeveloped MCS scheme. That doesn't necessarily mean adding another layer of bureaucracy to every project. It does mean being curious.

Which version of the MCS scheme is the installer operating under? Is their certification current and appropriate for the technology being installed? What calculations or technical evidence are required? Who has produced that information, and are they appropriately competent to do so? What evidence will be available following installation? Where will that evidence sit? And how does it connect with the project's wider PAS 2035 requirements? These aren't questions for the sake of compliance. They're questions that help everyone involved understand where responsibility sits and give the Retrofit Coordinator greater confidence in the overall solution. That's particularly important when several organisations are involved in delivering one retrofit programme.

More assurance is useful. Connected assurance is better

There is a bigger point here that goes beyond MCS. Retrofit has no shortage of standards, certification schemes, specifications, calculations and evidence requirements. Most exist for good reason. But residents don't experience a PAS 2035 process, an MCS process and an installer process separately. They experience their home. They experience whether it's warmer. Whether their energy bills have changed, the technology is easy to use or the work was explained properly. And whether somebody takes responsibility when something isn't right.

That's why we think the Retrofit Coordinator continues to play such an important role. Someone still needs to see the whole picture. The redevelopment of MCS has the potential to strengthen the assurance surrounding individual technologies. That's positive. But stronger assurance isn't simply about generating more evidence. It's about understanding where that evidence has come from, having confidence in the competence behind it and making sure it connects with everything else happening to the property.

So, what should Retrofit Coordinators do?

For now, we'd suggest keeping an eye on the transition rather than treating MCS:2025 as simply an installer issue. Understand what is changing. Check the certification status and scope of the installers you're working with. Think about who is producing the technical evidence you rely on and whether the appropriate competence sits behind it. And, as the new scheme beds in, pay attention to how information moves between installers, designers, Retrofit Coordinators and clients. Because ultimately, good retrofit isn't about collecting as many certificates, calculations and documents as possible. It's about being able to demonstrate that the right measures have been designed and installed properly, that they work together and that they deliver the outcome they were intended to achieve. We'd be interested to hear how other Retrofit Coordinators are approaching the MCS transition. Do you expect MCS:2025 to change the way you coordinate or assure projects?