The checklist
Check your installer is MCS certified.
It’s what makes you eligible for the grant, and it’s worth checking directly rather than assuming — especially if you’re going with an independent installer rather than a well-known name. Ask to see it.
Somewhere for materials to be delivered.
Pipes, radiators, and the cylinder often arrive before the install starts. You’ll need space for that — a garage, driveway, or spare room.
Groundworks done in advance.
If the outdoor unit needs a base, bracket, or any digging, that’s usually done before install week, not during it. Ask your installer when this needs to happen.
Clear access to every radiator.
Any room getting a new radiator needs to be cleared — furniture moved, floors accessible. This is easy to underestimate if it’s a full house of radiators.
Asbestos testing, if you have Artex ceilings.
Older Artex can contain asbestos. If your ceilings need drilling into (for pipework or fixings), this usually needs checking and signing off first.
Loft signed off for weight, if the cylinder’s going up there.
A hot water cylinder is heavy once it’s full. If it’s being fitted in the loft, the loft structure needs to be checked and approved to take that weight.
An approved location for the cylinder.
Wherever it goes — loft, airing cupboard, garage — it needs sign-off in advance, not decided on the day. Cylinders usually stand 1.5–2m tall and 50–80cm across; if you don’t have room for one, ask about a heat battery instead, which takes up to four times less space.
Space for an indoor heat exchanger, if your system has one.
Some heat pumps keep the heat exchanger indoors instead of built into the outdoor unit — about the size of a boiler, roughly 50–80cm tall and wide, 30–50cm deep. If you’re replacing a boiler, it’ll usually fit in the same spot.
Electrics sorted: switches and meter box.
Heat pumps need their own power supply, which usually means new switches and sometimes extending your meter box or consumer unit. This is often done by a separate electrician, so it’s worth asking early who’s doing it and when.
Scaffolding, if your outdoor unit needs height access.
This is sometimes an extra cost on top of your quote, not always included — worth checking. It also tends to go up well before install day and can sit there for weeks afterwards before it’s taken down. Mildly annoying, but normal — ask your installer roughly how long to expect it for.
Check your existing pipework isn’t too narrow.
Older houses sometimes have “microbore” pipework — thinner pipes than modern systems use. Heat pumps generally need wider pipes to move enough water around efficiently. Whether yours is wide enough depends on the exact size and your system design, so it’s a good question to ask at survey stage rather than assume. If it’s too narrow, replacing it can add real cost and disruption on top of everything else.
If you’re on LPG, check who’s decommissioning your old connection.
Some installers include disconnecting a standard mains gas boiler as part of the job, but LPG connections aren’t always covered the same way — you may need to arrange and pay for an approved engineer to decommission it separately, before install day one. Don’t assume it’s included; ask specifically if you’re not on mains gas.
None of this is unusual — it’s just not obvious until someone tells you. A good installer should walk you through all of it at the survey stage. If they don’t mention any of this, ask.
Summary
The short version
Somewhere for deliveries
Pipes, radiators, and the cylinder often arrive before install week even starts.
Electrics need sorting early
New switches, sometimes a bigger meter box — ask early who’s doing this and when.
Sign-offs happen in advance
Cylinder location, loft weight, asbestos checks — settled before install week, not during it.
Check your pipework width
Older “microbore” pipes may need replacing to work well with a heat pump.
Ask about your specific fuel
LPG decommissioning isn’t always included the way mains gas disconnection is.
Just Ask: Heatpump
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