Labour vs boiler unit cost: where your money actually goes Why “cheap boilers” usually cost more
If you’ve searched “boiler cost and installation” or “boiler installation cost”, you’re not trying to become an expert — you’re trying to understand why quotes vary so much in London.
Why did you get one quote for £1,900 and another for £4,200 — and are you being mugged off?
This page exists to resolve that tension. Not to sell you a boiler, not to push prices — but to explain where the money actually goes when a boiler is installed properly.
Want the real ranges and what drives them? See our main guide to boiler prices and installation cost in London, including realistic fitted totals and the factors that push quotes up.
The mental mistake almost everyone makes
Most homeowners assume the boiler itself is the expensive bit.
A metal box.
A few pipes.
A few hours of work.
So when someone sees “Boiler only £899”, the natural assumption is:
Right — fitting can’t be that much on top.
That assumption is where people get burned, especially when the quote ignores what actually makes a boiler safe, legal, and reliable long-term.
It’s also why two people searching “cost of installing a new boiler” can see wildly different numbers. The real cost is usually in the labour, checks, materials, and compliance — not the boiler box itself.
The real split: boiler vs labour (roughly)
On most London installations, the boiler unit itself is only 35–50% of the total.
The rest is everything required to make that boiler:
- Safe
- Legal
- Efficient
- Reliable
- Insurable
- Sellable with the property
Typical real-world example:
Total installed cost: £3,200
Boiler unit: £1,200
Labour, compliance, setup: £2,000
And that £2,000 is not “fitting time”. It’s the work that keeps the system safe, compliant, and actually working properly for years.
What “labour” actually includes
Comparison sites talk about “installation” as if it’s just hours on site. It isn’t. Proper installation is a bundle of checks, upgrades, protection work and documentation.
1. Removing the old boiler properly
Draining the system, disconnecting safely, disposing of components legally, and dealing with seized valves, brittle pipework or old fittings that crack when touched.
In older London properties, this is often unpredictable — and it affects the real boiler installation cost.
2. Gas safety and pipe sizing
Checking whether the existing gas supply can actually support a modern boiler is non-negotiable.
Undersized gas pipes are common in flats and older houses — upgrading them takes time, access, and skill.
3. System flushing and protection
A proper flush, magnetic filter installation, inhibitor dosing, and radiator balancing are what stop a new boiler failing early.
This is where cheap installs cut corners — and why “cheap” becomes expensive later.
4. Controls and efficiency setup
Modern boilers rely on controls to run efficiently. Thermostats, programmers, modulation settings — many rushed installs never optimise these properly.
That’s why some homes see little to no energy savings after fitting a new boiler.
5. Legal compliance and paperwork
Gas Safe notification, benchmark logs, warranty activation — miss any of this and the problems show up later.
- Warranties can be void
- Insurance claims can fail
- Property sales can be delayed
Why cheap boiler installs fail long-term
The pattern is usually the same:
Someone finds “New boiler installed from £1,999”.
What often sits behind that headline:
- Entry-level boiler (not always bad — but often basic)
- Flush skipped or rushed
- Old pipework left untouched
- No proper commissioning
- Warranty only partially registered (or missing support documents)
A few months later: noise, pressure drops, uneven heating, radiators not warming properly.
The boiler didn’t save money — it delayed the real cost. If you’re budgeting, use our pricing pillar for new boiler fitted cost ranges and what typically pushes totals up.
If you’re dealing with breakdowns after a rushed install, see our boiler repairs in London page.
Why London labour costs more (and why that’s normal)
London installs are rarely straightforward.
- No parking or restricted access
- Congestion delays
- Flats above shops
- Shared or awkward flues
- Victorian-era pipework
- Management company restrictions
A job that takes half a day elsewhere can take a full day (or more) here.
That isn’t inefficiency — it’s reality. It’s also why London pricing ranges are wider than people expect.
Helpful comparisons
If you’re comparing combi quotes specifically, examples help more than headlines. See combi boiler installation prices in London.
For a proper benchmark, including realistic fitted totals and what moves the price, use the main boiler prices and installation cost in London guide.
The bottom line
This article isn’t about selling installs, justifying prices, or flexing expertise.
It’s about explaining reality clearly — so homeowners understand what they’re paying for, and why wildly different quotes exist.
If you want a quick sanity-check on a quote, call 07727 154746 or use our contact page.
Common questions
Why does boiler installation cost more than the boiler itself?
Because installation includes gas safety checks, pipe sizing or upgrades, system flushing, controls setup, commissioning, and legal compliance. The boiler unit itself is often only 35–50% of the total.
Are cheap boiler installation deals a false economy?
Often, yes. Cheap installs usually cut corners on flushing, commissioning, or pipework. That leads to breakdowns, inefficiency, and higher long-term costs.
Why are boiler installation labour costs higher in London?
Restricted access, parking issues, old pipework, flats above shops, and shared flues can add time and complexity, so labour becomes a bigger portion of the quote.
Where can I see realistic boiler replacement cost UK ranges?
Use our new boiler cost and installation guide for realistic London ranges and what typically pushes prices up.