How to price a boiler installation quote (2026)
Boiler installation is one of the highest-value single jobs a heating engineer carries out. A straightforward combi swap in a terraced house can generate £2,000–£3,000 in revenue in a single day. Done well and priced correctly, it is also one of the best-margin jobs in the trade. Done badly — with missing line items, optimistic labour estimates, or a price that does not reflect the materials used — it can quietly lose you money even as it feels like a busy day.
This guide breaks down every component that goes into a boiler installation quote, with realistic UK pricing figures for 2026, and explains how to present quotes in a way that wins jobs against cheaper competitors without dropping your price.
What goes into a boiler installation quote
A boiler installation quote has five distinct cost areas: the boiler itself, all associated materials (flue, fittings, filter, inhibitor, controls), labour, any system preparation work (flushing, power flush, pressurisation), and VAT. Each needs to be calculated correctly. Most engineers who undercharge do so because they lump materials together, forget incidental items, or use a day rate that does not account for time spent on preparation and commissioning.
A complete cost checklist for a standard combi-to-combi replacement in an average semi-detached property:
- Boiler (cost price from supplier)
- Flue kit and any extensions or bends
- Magnetic system filter (e.g. Adey MagnaClean, Fernox TF1)
- System inhibitor (full system dose)
- Thermostat / smart controls (if upgrading)
- Radiator valves if replacing
- Pipe fittings, solder, flux, PTFE tape
- Flue guard (if required by building regs)
- Condensate pipework extension (if required)
- Labour: removal, installation, commissioning, Gas Safe paperwork
- Chemical flush or power flush (if system requires it)
- Disposal of old boiler
- VAT at standard rate (20%)
Boiler supply margin: dealer vs distributor pricing
How you buy the boiler has a significant impact on your margin. Trade counter pricing from a merchant like City Plumbing, Plumbase or Wolseley is the most common route for smaller heating businesses. Typical trade prices for popular combi boilers in 2026:
| Boiler model | Trade price (ex. VAT) | Typical sell price | Margin |
|---|---|---|---|
| Worcester Bosch 4000 30kW | £680 | £850 | 25% |
| Viessmann Vitodens 050-W 30kW | £720 | £900 | 25% |
| Vaillant ecoFIT pure 30kW | £640 | £800 | 25% |
| Ideal Logic Max 30kW | £480 | £620 | 29% |
If you are installing 10+ boilers per month, it is worth exploring direct dealer accounts with manufacturers. Worcester Bosch, Vaillant, and Viessmann all offer approved installer programmes that provide preferential pricing, extended warranty schemes you can sell to customers, and marketing support. Dealer pricing can be 10–20% lower than trade counter, which flows directly into margin.
Do not buy boilers from Amazon or consumer-facing retailers even if the price looks attractive. Manufacturers will not honour warranty claims for boilers not purchased through the trade supply chain, and you are personally liable for the installation.
Labour rates for boiler installation: regional benchmarks
A like-for-like combi swap in a straightforward location typically takes 4–6 hours for one engineer. Factor in time for: removing the old boiler and disconnecting pipework; fitting the new boiler; running the flue; connecting gas, water, and electrics; setting controls; inhibiting and filling the system; commissioning and testing; and completing Gas Safe documentation. Do not forget the site survey visit if you did one separately.
Labour rate benchmarks for boiler installation in 2026 (ex. VAT):
| Region | Labour (install only) | Day rate equivalent |
|---|---|---|
| London (zones 1–3) | £600–£900 | £600–£750/day |
| South East (M25 corridor) | £500–£750 | £500–£600/day |
| Midlands | £400–£600 | £400–£500/day |
| North West / North East | £350–£550 | £380–£480/day |
| Scotland | £350–£500 | £360–£450/day |
If you are using a subcontractor or labourer to assist, add their cost to the labour line. Two people on a job often reduces the clock time but increases the total labour cost — make sure your quote reflects the actual cost, not just the principal engineer's time.
What most engineers forget to include
The items most commonly missed from boiler installation quotes are not the big ticket items — they are the smaller materials and services that individually seem trivial but together can represent £200–£400 of real cost on every job.
- Flue extension pieces and elbows. Standard flue kits cover a typical run. Any extension, extra bend, or non-standard exit point adds material cost. Budget £30–£80 for extensions; more for low-level flue kits or concealed flue runs. Always measure the flue route before pricing.
- Magnetic system filter. Building regulations now require a filter on new boiler installations. An Adey MagnaClean Pro or Fernox TF1 costs £50–£80 at trade. Do not absorb this into your margin — line-item it on the quote.
- Inhibitor dose. A full system dose of Fernox F1 or Adey MC1+ for an average 10-radiator system costs £15–£25. Small cost, but it adds up across 100 jobs.
- Chemical flush. If the system is older or the water is visibly dirty on draining, a chemical flush (Fernox Cleaner F3 or equivalent, circulated before fitting the new boiler) should be priced at £80–£150 labour and materials. A power flush on a heavily sludged system costs £300–£600 and should always be a separate line item.
- Smart controls and thermostat. The Boiler Plus regulations (England and Wales) require time and temperature zone control on combi installations. If the customer is upgrading to a smart thermostat (Nest, Hive, Honeywell T6R), price the supply and installation of controls as a separate item: typically £120–£280 supply, plus 1–1.5 hours labour.
- Condensate run. If the condensate pipe needs to be extended or rerouted to an internal drain, budget materials and additional time. An external condensate run in an unheated area may also require lagging, which must be included.
- Old boiler disposal. Taking away the old boiler and associated pipework is a service. Most engineers absorb the skip or tip cost silently. Charge £30–£60 for disposal, or factor it into your overhead recovery.
VAT on boiler installations
Standard-rate VAT (20%) applies to the majority of boiler replacement jobs. However, a reduced rate of 5% VAT applies to the supply and installation of certain energy-saving materials under HMRC Notice 708/6. In practice, this applies when installing a boiler as part of a broader energy efficiency upgrade — for example, installing a boiler alongside loft insulation, cavity wall insulation, or a solar thermal system — in a qualifying property.
From February 2024, the reduced rate was extended to include heat pumps and associated controls, but a like-for-like gas boiler replacement on its own remains standard-rated. If you are installing under a government scheme (Great British Insulation Scheme, ECO4), the VAT treatment depends on the specific scheme and whether you are a subcontractor or main contractor. Take advice from your accountant if you work on scheme-funded installations.
Always present your quoted price with VAT split out clearly. Customers see the total cost and understand what they are paying in VAT. It also avoids disputes later if a customer assumed the price was inclusive.
Quote presentation: how to win against cheaper quotes
The majority of customers who get three boiler quotes do not automatically choose the cheapest one. Research consistently shows that homeowners are risk-averse about boiler installations: a boiler that fails in January costs them far more in call-out fees and inconvenience than the savings from a cheaper upfront quote. Your job in the quote presentation is to reduce perceived risk and increase confidence in choosing you.
A detailed, itemised quote does this better than a single lump-sum figure. When a customer can see exactly what they are getting — the specific boiler model, the filter, the inhibitor, the controls, the system flush, the Gas Safe certificate, the warranty period — they can compare accurately with cheaper quotes. Cheap quotes are often cheap because they exclude items that the customer will be charged for on the day. A transparent quote protects you from that comparison.
Include your Gas Safe registration number prominently. Show the manufacturer warranty period (Worcester Bosch, for instance, offers up to 12 years when installed by an approved installer). State exactly what is included and, critically, what is not — so there are no surprises.
Example quote breakdown — combi swap, semi-detached, Midlands
When presenting this kind of detailed quote alongside a cheaper competitor's single-line “£1,800 supply and fit”, the customer can immediately see what the cheaper quote omits. Often, when you add back the filter, controls, flush, and disposal to the cheap quote, the real price differential narrows or disappears.
Trade2Base boiler installation quote templates
Building a full boiler installation quote from scratch takes time — especially when you are pricing on-site or straight after a survey visit. Trade2Base includes pre-built boiler installation quote templates that cover all the standard line items for a combi swap, system boiler replacement, or heat-only installation.
When you create a new boiler installation quote in Trade2Base, the template pre-populates with the standard line items. You update the boiler model and price, adjust the flue configuration, tick whether a flush or power flush is required, and select the controls package. The system calculates the totals, applies VAT, and generates a professional PDF quote branded with your Gas Safe number, company logo, and payment terms.
Customers can view and accept the quote online, digitally signing to confirm the order. You receive a notification the moment they accept. For heating engineers quoting 10–20 boiler jobs per month, the time saved versus building each quote in a spreadsheet or Word document is typically 30–45 minutes per job — the equivalent of a full week saved every month.