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 probably not trying to become an expert. You’re trying to understand why quotes vary so much.
Why did I get one quote for £1,900 and another for £4,200 — and am I 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 in London.
Want the full numbers? See our main guide to new boiler cost and installation in London, including realistic ranges and what affects boiler replacement cost UK homeowners end up paying.
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.
It’s also why two people searching “cost of installing a new boiler” can see wildly different answers. The real cost is usually hidden in the labour, checks, and compliance.
The real split: boiler vs labour (roughly)
On most London installations, the boiler unit itself is only 35–50% of the total cost.
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”. That’s the biggest misunderstanding of all.
What “labour” actually includes
Comparison sites talk about “installation” as if it’s just hours on site. It isn’t.
1. Removing the old boiler properly
Draining the system, disconnecting safely, disposing of old components legally, and dealing with seized valves or brittle pipework.
Older London properties make this unpredictable, and that affects boiler installation cost.
2. Gas safety and pipe sizing
Checking whether the existing gas pipe can actually support a modern boiler is non-negotiable.
Undersized gas supplies are common, especially in flats and older houses, and upgrading them takes time and skill.
3. System flushing and protection
A proper flush, magnetic filter installation, and radiator balancing are what stop a new boiler dying early.
This is where cheap installs usually cut corners, and why “cheap” often becomes expensive later.
4. Controls and efficiency setup
Modern boilers rely on controls to work efficiently. Thermostats, programmers, modulation settings — most rushed installs never optimise these properly.
That’s why some homes see no energy savings even after fitting a new boiler.
5. Legal compliance and paperwork
Gas Safe registration, benchmark logs, warranty activation — miss any of this and 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 always the same.
Someone finds “New boiler installed from £1,999”.
What usually happens:
- Entry-level boiler
- Flush skipped or rushed
- Old pipework left untouched
- No real commissioning
- Warranty only partially registered
A few months later: noise, pressure drops, uneven heating.
The boiler didn’t save money — it just delayed the real cost. This is a big reason boiler replacement cost ends up higher than expected over the life of the system.
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 boiler installation cost in London 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 full benchmark, including average cost of a new boiler ranges we’re seeing this year and what moves the price, use the main boiler cost and installation 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 fast 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.