UK plumbing & HVAC: compliance and subsidy pay better than pipework

About 126 UK plumbing, heating and air-conditioning companies publish a full profit-and-loss, booking £3.6bn of combined turnover — and the map they draw is upside down. The biggest hands-on contractor in it, Integral UK, lost £8.8M on £293.6M of work while revenue fell 19% and headcount 15%. The best profit-to-payroll ratio in the entire trade belongs to Berks Insulation — 21 employees, £81.2M of turnover, £17.4M of pre-tax profit — an energy-efficiency retrofit business whose economics come from grant-and-obligation schemes, not hourly labour. Between those poles, the steadiest money is social-housing compliance work (the Sureserve group books roughly £246M across the three regional companies in this category, all profitable), and the trade’s fastest growth — heat pumps — is being bought at a loss. Fitting pipe is the hard way to earn a living here; the returns sit wherever a regulation, an obligation or a subsidy writes the invoice. Figures are approximate — verify against a company’s own accounts before relying on any single number.

Read the names first

Four things change how you read every number below.

Not everything on this shelf is a contractor. The category’s giants include several businesses that don’t send an engineer to site on contract terms at all. Homeserve Membership (£279.9M, £56.7M profit) sells home emergency cover — recurring policy income with insurance-like economics, which is why its 20% margin towers over every installer’s. Carrier Solutions UK (£143.4M) and Johnson Controls Building Efficiency UK (£131.7M) are the British arms of two global air-conditioning and controls groups — as much equipment sales and service as contracting. Grant Engineering (UK) (£78.4M) is an Irish boiler and heat-pump maker’s UK sales operation, and further down, Swegon (23.3% margin) and Aermec UK sell Swedish and Italian ventilation and chiller kit. They’re labelled in the giants table and kept out of every competitive read.

One group holds three of the top seven slots. Sureserve Compliance South (£100.3M), Central (£96.4M) and Northwest (£48.9M) are regional companies of one compliance group — count them once, as a combined ~£246M (the slice of the wider Sureserve group that lands in this category), or the top of this market looks more crowded than it is.

What you see is the top of the trade. Britain has tens of thousands of plumbing and heating firms — 1,881 substantial enough to register in this category alone — but the one-van plumber and the small local firm publish accounts too small to carry a profit figure. This map covers the commercial, industrial and social-housing top slice.

Margin is not margin across models. A mechanical contractor on lump-sum terms passes enormous material and subcontract costs through its top line and keeps a sliver; a compliance business earns repeat framework revenue on its own engineers; a retrofit installer’s turnover is scheme funding routed through subcontract crews; a kit-maker’s arm earns a distribution margin; Homeserve earns premiums. Comparing their percentages tells you about their models, not their management — this report doesn’t.

The giants

The contrast at the top is the whole story. Integral UK — the biggest genuine installing-and-maintaining business on the map — is shrinking on both axes and losing money; cutting revenue 19% and staff 15% in the same year is a business contracting, not one defending margin. Meanwhile the two retrofit specialists, Berks and Borthwick, grew 28% each and made a combined £27.4M — more than every hands-on contractor in the giants table put together. The Sureserve rows need splitting: Central’s +16% is organic, riding the gas-safety and compliance cycles that social landlords must fund every year regardless of the economy — but South’s +55% is the group’s own restructuring, the first full year after it merged its K&T Heating and Swale Heating businesses into one southern company in late 2024, folding Swale’s order book (and its engineers — hence staff +48%) into these accounts.

The shape of the market

Below the giants this is a healthy trade. The heart of it is the £5–25M regional mechanical contractor — 60 companies, 82% profitable — and the £25–100M tier above is even stronger at 86%. The graveyard is only at the bottom: below £1M just 38% make money, though barely a dozen companies that small publish full figures at all. Unlike the roll-up-scarred markets we’ve mapped, there’s no loss-making acquisition tier here; the mid-market simply gets on with it.

The compliance economy

Strip out the kit-sellers and the subsidy plays and the best reliable money in this trade is regulated, repeating work for social landlords: annual gas-safety checks, boiler servicing, heating replacement under framework contracts. The Sureserve group is the template — its Central company alone made £9.9M at 10.3% — and a whole tier of the best-run table works the same seam: T Brown Group (£65.3M, family-run since the 1970s), Oakray (£45.6M), Scotland’s Saltire Facilities Management (£31.4M at 10.8%), BSW Heating (£27.6M), Switch2 Energy (£28.3M, heat networks). Margins run 4–11% — unspectacular, but attached to statutory obligations that renew every year. It’s the same lesson as our electrical contractors map, where the framework and maintenance specialists out-earn the lump-sum installers: recurring beats project, and regulation is the best salesman in the building trades.

The best-run genuine contractors, £5–100M, profitable at ≥4%, with the group companies, kit-sellers and scheme-funded retrofitters set aside:

…and 8 more clear the same bar. The standout margins (E Plan at 15.8%, CPS at 10.5% while growing 38%) belong to firms mixing installation with service and energy work — the pure install-only model rarely clears 7%.

The subsidy economy

The strangest economics on the map belong to the retrofit installers. Berks Insulation: £81.2M of turnover, £17.4M of profit, 21 employees — nearly £4M of revenue per head, which no amount of hands-on labour produces. Broad Oak Properties Eco runs £31.8M through 9 staff; Borthwick (£64.2M, 15.5%) and MWA Eco Systems (£17.3M, up 50%) carry more of their own workforce but ride the same wave. This is the shape of Britain’s energy-efficiency obligation and grant schemes: funding flows to accredited installers who deliver through subcontract crews, so the accounts show scheme revenue with a skeleton payroll.

Read those margins with care in both directions. They’re real profit — but they’re attached to policy, not to a customer base. When a scheme is retuned, paused or tightened (as these schemes regularly are), the revenue line can halve without the company doing anything wrong. A 21-person business booking £81M is magnificent while the funding window is open; it is not a 21-person business you can value like a contractor with 400 engineers and a framework book.

Growth, read with care

(One mid-size firm with an implausible headcount swing in its accounts is left out of this table.)

The most telling row is the top one. CB Heating is a heat-pump installer that has nearly tripled revenue while hiring 51% more staff — and lost £1.6M doing it, an 11.6% negative margin. That is what the heat-pump transition looks like in the accounts right now: the volume is arriving, energy-supplier and grant money is behind it, and the installation economics don’t yet pay. Contrast Woodford Heating & Energy — +65% to £57.9M installing for housebuilders, hiring 21% more staff, and landing at exactly breakeven: growth priced to win work, not to bank it. The genuine article is CPS Building Services (+38%, 10.5% margin, staff +15%) — profitable, hiring-backed and rare. And Sureserve South’s +55% isn’t market growth at all: it’s the group’s 2024 merger of K&T Heating and Swale Heating into a single southern company — the first year with Swale’s book inside these accounts — a restructure, not work won from the market.

Market structure

This is one of the least concentrated markets we’ve mapped: the top 5 hold 26.6% of visible turnover and the top 10 under 39% — and even that overstates it, since the head of the curve is padded with the non-contractors (Homeserve, the kit arms) and one group counted three times (Sureserve). Heating and plumbing remains a genuinely regional trade: the main contractors who hire these firms consolidate scale in our building contractors map, while the wet trade below them stays fragmented across a hundred-plus regional operators.

Ownership and vintage

Ownership says the consolidators haven’t arrived. Of the 126 companies, 69 are individually owned against 56 corporate-owned, and only about 6% carry a Holdings/Group/Bidco-style name — the fingerprint of a buyout — versus 15% in markets like pubs. This is still a family-firm trade, which is precisely what makes it a target: fragmented, obligation-backed revenue is the classic buy-and-build thesis, and the Sureserve group shows what the assembled version looks like.

The vintage split tells the sector’s story in two cohorts. The biggest is pre-1990 (33 companies) — the established mechanical and heating firms, some tracing to the 1950s and 60s, that anchor the mid-market. But nearly everything in the subsidy and heat-pump economy dates from 2009–2015: Borthwick (2009), Berks (2013), MWA (2013), E Plan (2013), JCW (2013), CB Heating (2015). The old cohort fits pipe; the young cohort was built to catch policy money.

What the map shows

1. Installing at national scale is the hard way to earn a living. The biggest hands-on contractor, Integral UK, lost £8.8M while shrinking on both axes; the £25–100M regional tier, 86% profitable, is where contracting actually works.
2. Compliance is the steady core. Social-housing gas-safety and heating frameworks (Sureserve’s ~£246M across the three companies here, T Brown, Saltire, BSW, Oakray) earn 4–11% on revenue that statutory obligations renew every year.
3. Subsidy is the margin outlier — and the fragile one. Scheme-funded retrofitters (Berks: £17.4M profit on 21 staff; Broad Oak: £31.8M through 9) post the best profit-to-payroll in the trade, attached to policy rather than customers.
4. The heat-pump race is being run at a loss. CB Heating tripled revenue and hired 51% more staff to lose £1.6M — the transition’s volume has arrived before its installation economics.
5. Several “giants” aren’t contractors at all. Home emergency cover (Homeserve, £56.7M profit) and the UK arms of global equipment makers (Carrier, Johnson Controls, Grant, Swegon) sit at the top of the table on entirely different economics.
6. It’s still a family-firm trade — 69 of 126 individually owned, top 5 at 26.6% share — the classic pre-consolidation profile, with Sureserve as the proof-of-concept roll-up.

Methodology and caveats

This covers only the 126 UK plumbing, heating and air-conditioning companies that publish a full profit-and-loss; the one-van and small-firm tail — most of the trade by headcount — reports figures too small to appear. Some companies in the category are equipment makers’ sales arms, home-emergency cover providers or scheme-funded retrofit businesses rather than contractors; they’re labelled and kept out of competitive comparisons, and business-model labels are directional. Group companies report separately (the three Sureserve regional companies are one business), so combined-turnover and concentration figures count some organisations more than once. Margins across different models — lump-sum contracting, compliance frameworks, distribution, cover plans, scheme funding — are different economics and never directly comparable. Large swings can reflect contract transfers within groups or scheme-funding cycles rather than market wins or losses. Figures are approximate — verify any specific figure against the company’s own accounts. This is analysis, not financial advice.