Every installer's spreadsheet setup started with a job that needed doing. Someone had a heat loss to run on a Sunday night, no software worth the licence fee, and a decent grasp of formulas. So they built it. Then a tab for emitters, a tab for the cylinder, a quote template that pulled from both, and a folder structure that made sense to exactly one person.
That was the right call at the time, and it's worth saying so before anyone makes the case for replacing it.
What the spreadsheet actually got right
It was shaped around how that business works, which no off-the-shelf product ever is. It cost nothing. It changed the same afternoon you decided it needed to change. It quietly encoded years of hard-won judgement, the fudge factor on that estate of 1930s semis, the way you like a quote laid out.
Most spreadsheet workflow setups aren't inaccurate. The maths in them is usually fine. That's not where they fail.
Where they stop scaling
They fail at the second person, and at the second time you touch the same job.
Data gets entered more than once. Room dimensions go into the survey sheet on site, into the heat loss file that evening, into the quote, then into the MCS documentation. Four entries, four chances to transpose a number, and no way of knowing which version is right when they disagree.
Files drift. There are now three copies of the calculator in circulation and the newest one isn't on the shared drive. Survey notes live on a phone, in a notebook, or in someone's head, and the job that gets picked up by a second engineer starts with a phone call rather than a file.
And the whole thing sits with one person. Every installer business running on spreadsheets has somebody who understands the workbook, and their annual leave is a business risk. That's the ceiling on heat pump business scaling: not skill, not demand, just how many jobs can pass through one person's file.
The market changed shape, not just size
This isn't a growth story, and it's worth being straight about that. The UK passed 250,000 certified heat pump installations in early 2026, and 2025 was the strongest year on record with over 60,000. But heat pump installations in the first half of 2026 ran 17% below the same period in 2025, even while certified renewables overall hit a record 210,000. Around three quarters of heat pump installs are government-funded, and a quarter of 2026 installations were on new build.
Read that as an installer rather than an analyst. The pipeline is lumpier, more of it depends on scheme timing, and more of it is repeat work across similar properties. A choppy market punishes a slow survey-to-quote cycle harder than a booming one does, because the job you took four days to price has already been quoted by someone else. Installer productivity stops being an efficiency nicety and starts deciding which jobs you win. And twelve near-identical plots on a new build site is where a spreadsheet is at its most wasteful, you rebuild the same job twelve times because a file can be a template or a record but never both at once.
What the alternative actually looks like
Purpose-built heat pump design software isn't a spreadsheet with a nicer interface. The difference is that survey data is entered once and everything downstream reads from it: the heat loss, the emitter schedule, the cylinder, the MCS documentation. Change a U-value and the radiator schedule changes with it, because it was never a separate file to begin with.
The start of the job is where it shows first: a postcode pulling property data in before you've measured anything, rather than a blank sheet. The end of the job is where it pays.
Three questions worth asking before you move
Does it produce the MCS documentation you actually need, or documentation you'll be re-typing? Can you get your data out again if you leave? And does it follow the order you survey in, or the order a developer imagined you survey in, as MCS installer software that fights your site routine gets abandoned by March.
Those are fair questions to put to any of these heat pump business tools, including ours.
Start your free trial - 30 days, no card required and the postcode lookup fills the first part of your next survey before you've measured anything.
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