How much should you charge for a boiler swap?

A like-for-like combi swap in the UK in 2026 typically sells somewhere between £1,900 and £2,800 all-in, and yet two engineers quoting the same job can be £600 apart and both be “right”. The difference is rarely the labour. It is what each one has decided to include, absorb or forget. Price the parts deliberately and the number defends itself. Here is the breakdown.

Ranges below are for straightforward domestic swaps. System conversions, relocations and anything involving a loft tank are different jobs; price them as such.

The five parts of a boiler swap price

1. The boiler and flue

The single biggest line, and the one that moves most by brand and warranty length. Quote from a live merchant price, not memory: boiler prices have moved enough in the past two years that last winter’s figure quietly costs you money. Name the model and warranty on the quote; “Worcester 4000, 10-year warranty” sells better than “boiler”.

2. Labour

A straight combi-for-combi swap on the same wall is typically a day, one and a half with awkward access or a flue rerun. Price your day honestly, including the second pair of hands if you use one. If your day rate has drifted since you last checked it, run it through the day rate calculator before quote season.

3. The flush

A proper system flush protects the new boiler and, in most cases, the warranty. Put it on the quote as its own line: it is real work with real value, and when it is visible the customer understands what happens to the price if they decline it, and whose problem the sludge becomes.

4. The parts everyone forgets

Magnetic filter, condensate run, gas pipe upsizing where the regs require it, flue plume kit, chemical inhibitor. Individually small, together £250 to £450 of real cost. These are the lines that separate an accurate quote from an optimistic one.

5. Certification and commissioning

Gas Safe notification, commissioning, benchmark, handover. Price it and print it; it reassures exactly the kind of customer you want.

A worked example

Like-for-like combi swap, same wall:

• Boiler and flue, supplied: £1,240
• Installation labour: £520
• System power flush: £480
• Magnetic filter, supplied and fitted: £140
• Commissioning, notification and handover: £120

£2,500 in five legible lines. The customer comparing you against a one-line “£2,150 supply and fit” text message can now see what the £350 buys, and the conversation shifts from price to value, which is the only conversation you win.

The extras that carry the margin

The smart money on a boiler swap is in the tickable add-ons: smart thermostat, heated towel rail, an extra radiator while the system is drained, upgraded controls. Offered as priced options on the quote, they get ticked far more often than they get agreed on the phone afterwards, because the customer is already in spending mode and the incremental number looks small next to the boiler. A ticked £180 thermostat at acceptance costs you an hour; sold cold in November it costs you a call-out. If a radiator upgrade is in the mix, the free BTU calculator sizes it in seconds.

Take the deposit before you order the boiler

The boiler is a four-figure item that you order and the customer can cancel. A 20% deposit taken by card at acceptance means the kit is funded before it is on the van, and the odd cold-feet customer cancels before the merchant order, not after. It also fixes the cash-flow gap that makes January miserable. The wider case is in how to get paid faster as a tradesperson.

Speed wins boiler work more than price does

A dead boiler is an emergency purchase. The homeowner has no heating, two quotes coming “later in the week”, and yours arriving the same afternoon with a model name, a warranty, five clear lines and a pay-the-deposit button. Same price, first in writing, wins.

That flow is what Snapquo built for plumbers and heating engineers does: your boiler packages, flush and extras saved once as items, the quote assembled in the kitchen in about a minute, add-ons the customer ticks, the deposit taken on accept, and the balance invoiced in one tap when the heating is back on. The first few documents are free, so quote the next swap with it and see what same-day does to your win rate.