Questions for your green smart-tech installer

MCS (Microgeneration Certification Scheme) is the industry standard for renewable technology installations - including solar, battery, and heat pumps. It’s basically a government-backed mark of quality that says your system is designed and installed to a high standard.

If your install isn’t MCS certified, you can’t claim Smart Export Guarantee (SEG) payments for the energy you generate. It can also make it harder to use your installation as a selling point if you move house..

💡Tip: No MCS = no SEG payments

Look for HIES (Home Insulation & Energy Systems) or RECC (Renewable Energy Consumer Code). Both provide insurance-backed guarantees and deposit protection, so if a company goes under before or after your install, you're not left out of pocket.

💡Tip: Ask specifically for HIES or RECC membership.

A lot of solar installers spring up when demand is high and disappear just as quickly. You want to be confident that whoever fits your panels will still be there in ten or fifteen years when you need support. It’s always a good idea to ask how long they've been trading and look them up.

Your panels will come with a manufacturer's product warranty, but that doesn't cover the installation itself. A solid workmanship warranty means the company stands behind the quality of their work, so if something goes wrong with how the system was fitted, they should sort it at no cost to you.

💡Tip: Ask specifically about workmanship, not just the panel warranty.

This can matter more than you realise - when a company uses third-party installers, standards can vary and accountability gets blurry. Finding out who's actually coming to your home (and if they're vetted and managed directly!)is worth knowing upfront.

DNO (Distribution Network Operator) applications are required before you can export energy to the grid. A well-run installer gets the export licence approved before booking your installation date, not after. This guarantees the exact hardware quoted will be the hardware installed, with no last-minute surprises.

Which? Trusted Traders independently assess and vet the businesses they list. They check everything from customer reviews to business practices and financial standing. It's not a rubber stamp anyone can buy, traders have to pass an assessment to get listed and can be removed if standards slip.

A good solar system comes with a way to monitor it. Ask whether there's a dedicated app, and find out what happens when something doesn't look right - is there someone you can actually speak to? Aftercare availability can be super important in order to get the most out of your system.

💡Tip: Ask about weekend and bank holiday support specifically.

Ask for reviews - and not just the ones on their own website. Independent platforms like Trustpilot or Google can be good places to look. You can also pay particular attention to how a company responds to negative reviews; that tells you as much about them as the positive ones.

MCS is the industry standard for renewable technology installations - including solar, battery, and heat pumps. It’s basically a government-backed mark of quality that says your system is designed and installed to a high standard.

A MCS-certification is required to access the Boiler Upgrade Scheme (BUS) grant, currently worth £7,500 towards a heat pump. Only MCS-certified installers can apply for this on your behalf. Without it, you’ll likely have to pay full-price for your heat pump.

💡Tip: No MCS = no BUS grant

Look for HIES (Home Insulation & Energy Systems) or RECC (Renewable Energy Consumer Code). Both provide insurance-backed guarantees and deposit protection, so if a company goes under before or after your install, you're not left out of pocket.

💡Tip: Ask specifically for HIES or RECC membership.

This is the most important technical question on the list. A heat loss calculation tells an engineer exactly how much heat your home loses on the coldest day of the year - they need that to work out the right size heat pump for your home. A pump that's too large will short-cycle and wear out faster; one that's too small won't keep you warm.

💡Tip: If they haven't done one, ask why and consider walking away.

Heat pumps work at lower temperatures than boilers, which means undersized radiators may not deliver enough heat to your rooms. A thorough survey should check whether your existing radiators and hot water cylinder are suitable, or flag what needs upgrading before installation begins. The survey is an important part of designing a system that actually works.

💡Tip: Ask if they’ll assess your radiators room by room

Heat pump installation is more complex than swapping a boiler - it involves refrigerant handling, electrical work, and system balancing. When multiple subcontractors are involved, accountability for the overall result can get murky. It's worth knowing who's ultimately responsible if something isn't right.

This one can catch some installers out. Not every installer includes decommissioning and removing of your old boiler in their quoted price. It’s worth clarifying upfront what's included, and asking how they'll leave your home at the end of the job - including tidying up and disposing of old equipment properly.

The heat pump market has grown fast, and not all installers who entered it will still be around in five years. You want a company that will answer the phone in 10 years if you need them - so it's fair to ask how established they are and what their track record looks like.

The heat pump unit itself will come with a manufacturer warranty, but that's separate from whether the installation was done correctly. A workmanship warranty covers the quality of the work itself, so if something goes wrong that the manufacturer wouldn’t cover, the installer should come back and fix it.

To keep them running at peak efficiency, heat pumps should be serviced annually. Some installers include a service plan as standard, others offer it as an add-on, and some don’t offer them at all! Either way, it’s a good idea to find out what ongoing support looks like before you sign.

Ask for reviews - and not just the ones on their own website. Independent platforms like Trustpilot or Google can be good places to look. You can also pay particular attention to how a company responds to negative reviews; that tells you as much about them as the positive ones.