MCS certification: what it means for cooling your home

MCS (the Microgeneration Certification Scheme) certifies installers and products for small-scale low-carbon heat - including the air-to-air heat pumps that cool your home in summer and heat it in winter from the same unit. If you are weighing up how to keep an overheating home comfortable, MCS matters for one concrete reason: it is the accreditation the £2,500 air-to-air grant requires.

Where MCS applies to cooling - and where it does not

There are two honest routes, and MCS only touches one of them.

The grant-eligible route (MCS). You are eligible for the £2,500 Boiler Upgrade Scheme grant only when an air-to-air heat pump replaces your fossil-fuel or electric heating and is fitted by an MCS-certified installer. The heat pump does your heating and your cooling, and the old system is decommissioned rather than kept alongside it.

The cooling-only route (not MCS). If you keep your existing boiler and simply add cooling, that add-on is not eligible for the grant, and it is not an MCS job. A pure air conditioning install - a single-split, multi-split, ducted or portable unit - is carried out by an F-Gas / REFCOM-registered engineer instead. (Grant rules as of August 2026 and subject to change.)

So the rule of thumb is simple: MCS is the grant-eligible heat pump that replaces your heating; F-Gas / REFCOM is a private-pay cooling install that keeps it.

Why the accreditation protects you

The same air-to-air unit that cools a top-floor flat - a home type our overheating model scores around 90 out of 100 - is the one MCS covers on the grant route. MCS certification means the installer works to a recognised standard, the job is registered, and the installation carries a workmanship guarantee under a consumer code. That accountability is part of why the grant is tied to MCS at all: public money only backs work that meets the standard.

Getting the accreditation right is not a technicality. An installer offering you an "MCS grant" on a split-AC unit that keeps your boiler has the routing wrong - that is an F-Gas / REFCOM job with no grant.

Check which route fits your home

Which accreditation you need follows directly from which system suits your home and whether you replace your heating. Our free cooling checker works that out from your address - your overheating score, the right system, your real grant eligibility and the matching accreditation - on screen, with no phone call and no cold-calling, ever.

Check your home in 60 seconds ▸