Why Two London Homes Get Very Different Boiler Quotes (Even on the Same Street)
If you’ve ever thought, “How did my neighbour pay one price and I’m being quoted something totally different?” — you’re not being dramatic. It happens all the time.
And it’s not always because someone’s trying it on. A boiler quote is basically an estimate of how complex the work gets once we start checking access, tracing pipe runs, confirming flue routes, and seeing what condition the existing system is in. In other words, the boiler itself might be predictable — the job around it often isn’t.
If you want a calm answer based on your actual setup (not a “from £999” headline), call 07727 154746 — we’ll ask a few practical questions and tell you what usually drives the price up or down.
If you’re mainly here because you’re researching boiler replacement cost UK (or the average cost of a new boiler) and you want proper price ranges for 2025, we keep that separate to avoid mixing “prices” and “reasons” on one page: full breakdown of new boiler costs here. This page focuses on why boiler quotes vary in London — the things that change the boiler installation cost.
Helpful next reads: how to get an accurate new boiler quote (without wasting time) and why “cheap” boiler installation quotes often fall apart in London.
The short version: you’re not paying for a boiler — you’re paying for the job around it
In a perfect world, replacing a boiler is simple: old one off, new one on, tidy pipework, clean flue route, safe test, paperwork done, home warm. When it’s like that, the cost to replace a boiler looks “normal”.
In London, it’s rarely like that. The boiler might be straightforward, but everything around it isn’t: access, parking, pipe sizing, condensate routes, old sludge, ventilation, electrics, cupboard space, flue distances, and whether we can isolate water without affecting shared supplies in flats.
Same street, different reality
Two homes on the same road can have totally different installs. One might be a straightforward swap in a kitchen cupboard. Next door could involve a relocated boiler, undersized gas line, awkward flue route, and a system full of black sludge that would destroy a new heat exchanger.
Quotes feel random… but they usually aren’t
A good quote is basically a risk assessment: how long it takes, what parts are needed, what upgrades are required for safe compliance, and what the building throws at you (especially in flats and older housing stock). That’s why new boiler installation cost can vary massively between two properties.
Who we are (and why we’re even writing this)
We’re ARA Services Ltd — a small team based in Forest Gate, East London. A lot of our days start around Romford Road, hop onto the A12, then end up somewhere central because… well, London does what it wants.
We’re Gas Safe registered and we’re the people who actually do the work — not a call centre passing your details around. We’ve also got 30+ Google reviews, many from real “boiler’s died, help” situations, where timing, safety and clean work matter more than fancy words.
This page exists because we’ve heard the same thing at kitchen tables for years: “I don’t mind paying… I just want to understand why it’s so different.” Fair question. So this is the plain-English answer — the stuff that changes boiler replacement cost.
What actually changes a boiler quote in London
1) Access: stairs, cupboards, and “where are we even putting it?”
Access sounds boring until you live it. A boiler on the ground floor with clear space? Lovely. A boiler tucked in a tight cupboard above a washing machine, with the flue boxed in, while you’re working sideways with your torch in your mouth? That’s a different job — and a different boiler installation cost.
Flats add another layer: lifts that don’t work, concierge rules, narrow corridors, and the classic one — “You can’t isolate that here, it’s shared.” Suddenly a “simple swap” isn’t simple.
2) Gas pipe size: the hidden upgrade nobody mentions in cheap quotes
This one catches people out. A modern boiler often needs a proper gas supply to run safely and efficiently. If a property is still on older, skinny pipework, you can’t just ignore it. Sometimes it’s fine. Sometimes it’s borderline. Sometimes it’s a hard no.
Upgrading a gas line can mean lifting floors, chasing walls, or re-routing in a way that stays neat and accessible. It’s not glamorous, but it’s real — and it’s a major reason two “cost of boiler replacement UK” estimates can be miles apart.
3) “Old installs”: what the last engineer left behind (or didn’t do)
London has a lot of older housing stock and a lot of “just get it working” history. We walk into homes in Leyton, Hackney, and bits of Islington where the boiler’s been kept alive like a 20-year-old car: it starts, it stops, it bangs a bit… but it’s been limping.
When we open the case and see undersupported pipework, messy electrics, seized isolation valves, and system water that looks like Guinness… the quote changes. Not because we want it to, but because fitting a brand new boiler onto a neglected system is asking for trouble.
4) The system condition: sludge, flushing, and protection
If the system’s contaminated, you’ve got two choices: pretend it’s fine (and deal with breakdowns later), or clean it properly so the new boiler isn’t taking the blame for an old system.
This is where you’ll hear terms like power flush, magnetic filter, inhibitor. Some quotes include these. Some don’t. That’s why one looks “cheap” and the other looks “high” — they’re not quoting the same job.
5) Flue route and condensate: the boring stuff that decides whether it’s compliant
A flue isn’t just a pipe you shove out the wall. Distances, terminals, clearances, neighbouring windows, and where it terminates all matter. Condensate has rules too — where it drains, whether it freezes, whether it needs routing internally.
In terraces off the A12 you might have easy external routes. In some flats, you’re dealing with awkward runs, boxed-in routes, or permissions. Again: different job, different quote.
6) London reality: parking, congestion, loading, and time
People outside London think we’re exaggerating when we talk about parking. We’re not. Some areas around Central London are a full extra hour of your day just getting close enough to unload safely, especially near busy stretches like City Road, Euston Road, or anywhere with constant restrictions.
That time doesn’t disappear. It lands in the quote — or it lands in the installer rushing the job to “make it work”. We’d rather price it honestly than sprint through a gas appliance install.
What a “good” quote usually includes (without trying to scare you)
You don’t need jargon. You need clarity. A solid quote normally shows (or at least explains) what’s being allowed for: time on site, compliance steps, protection measures, and the awkward bits that are specific to your home. That’s what makes boiler installation cost comparisons meaningful.
It’s specific
Not just “new boiler installed”. It should reflect your property type (flat/house), access, flue/condensate route, and whether pipework upgrades are expected.
It’s honest about uncertainty
Some things only show once we’re there — especially in older installs. A trustworthy installer will tell you what’s included and what could change, and why.
If you want the process side (what happens on the day, what’s checked, what should be registered), we keep a separate guide here: how a proper boiler installation is handled. If you’re trying to avoid back-and-forth and just want an accurate quote faster, read: how to get an accurate new boiler quote without wasting time.
Three real-world examples of why prices jump
Example 1: “It’s a straight swap”… until it isn’t
We had one near Stratford where the customer was told it was a straight swap. On the surface, yes: combi in a kitchen cupboard. But once we checked, the gas supply was borderline and the isolation valves were basically decorative. Add in system water that wasn’t clean, and suddenly the “simple” job needed protection and prep.
Example 2: Flat install, building rules, and a flue route problem
Another job not far from Old Street — the boiler itself wasn’t the drama. The building rules were. Access windows, timings, where we could run the condensate, and what we could and couldn’t touch without approvals. The quote was higher than a “quick price” firm, but it was priced like reality, not best-case.
Example 3: The “cheap quote” that ignored the system condition
This one is common. Customer gets a low quote that basically assumes everything is perfect. Then the boiler’s fitted onto a dirty system, and a few months later it’s noisy, error codes, circulation issues. Now everyone’s arguing about whose fault it is. This is exactly why cheap boiler installation quotes often fall apart in London.
A practical way to compare quotes:
- Ask what’s allowed for: gas pipe size, flue/condensate route, cleaning/protection, controls, disposal, testing and paperwork.
- Ask what could change on the day (and why).
- Then compare like-for-like — not “headline price vs headline price”.
What we actually do (so you know who you’re talking to)
ARA Services isn’t “just boilers”. We’re a heating, plumbing and electrical team, which helps because boiler jobs don’t live in a bubble. Controls, wiring, condensate routing, isolation valves, leaks — it overlaps.
- Boiler replacements and like-for-like swaps
- Combi upgrades and system changes (when it genuinely makes sense)
- Boiler relocations (when the layout demands it)
- Heating controls and smart thermostat installs
- System cleaning, filters, inhibitors and long-term protection
- Fault finding and repairs when a replacement isn’t needed
If you’re specifically comparing combi swap numbers (and want to understand why one combi quote is higher than another), we keep examples here: real combi boiler installation pricing examples. And for broader 2025 price ranges (often searched as “boiler replacement cost UK” or “average cost of a new boiler”), use: our London boiler cost & installation guide.
Why people choose us (it’s usually not because we’re the cheapest)
Most customers who call us have already had one quote that felt too good to be true… or one that was so vague it might as well have been a text message. What people want isn’t a bargain. It’s confidence: “Are we comparing the same job?”
We’re happy to say “you don’t need a new boiler” if that’s the truth. We’re also happy to say, “This will cost more because the gas line needs upgrading and the system needs cleaning.” It’s not the fun answer — but it’s the honest one.
If you’re collecting quotes, ask each installer the same simple question: “What in my house is making the job harder?” If they can’t answer, the quote’s not really a quote — it’s a guess.
What customers mention in reviews (the pattern is pretty consistent)
We won’t dump a wall of reviews here. But the themes come up again and again: people mention we turn up when we say we will, we explain what’s happening in plain English, and we leave the place tidy.
- One customer described a full boiler replacement where the team worked straight through and cleaned up properly afterwards.
- Another mentioned we identified the issue quickly and fixed it without fuss — professional, no drama.
- We also get a lot of “fixed it on the first visit” feedback, which is usually down to proper diagnosis, not luck.
We’re a local team working across East and Central London. If you want to check basics first, start at the ARA Services homepage.
FAQ (the ones people actually ask, not the generic stuff)
Why did one engineer quote in 10 minutes and another wants photos / a visit?
Because the fast one is pricing “best case”. Photos (or a quick survey) reveal the stuff that changes the quote: gas pipe size, flue route, condensate drain, controls, access, and the condition of the existing system. If someone can price your home without seeing anything, they’re either guessing… or they’ll “discover” extra costs later. If you want a simple checklist, use: how to get an accurate new boiler quote without wasting time.
Is it normal for a flat to cost more than a house?
Often, yes — not always, but often. Flats come with access rules, shared services, awkward routes, and time. A two-bedroom flat can be trickier than a three-bedroom house if the building setup is difficult.
What’s the biggest “hidden” cost factor you see in London?
Gas supply upgrades and system condition. If the pipework needs changing or the system’s full of sludge, the job isn’t just “swap boiler and leave”. That’s where quote gaps get wide — and why “cost of boiler replacement UK” searches can be misleading without context.
Do I always need a power flush?
No. Sometimes a chemical clean and proper protection is enough. But if the system water is filthy, radiators are cold at the bottom, or the old boiler’s been failing for a while, cleaning becomes the difference between a reliable new install and a callout later.
How do I compare quotes fairly without becoming a boiler expert?
Ignore the headline number for a minute and compare what’s included: protection (filter/inhibitor), system clean if needed, controls, compliance, flue/condensate allowance, disposal, and paperwork. If you want the 2025 price ranges to sanity-check against (often searched as “boiler replacement cost UK” or “how much is a new boiler”), use our main London boiler cost guide.
If you’re trying to decide between two quotes and you want a second opinion on what’s driving the difference, you can call 07727 154746 or use our contact page. No scripts — just a quick “what’s likely going on in this type of property?” conversation.
ARA Services Ltd • Based in Forest Gate, East London • Working across Stratford, Leyton, Hackney and Central London. Gas work carried out by Gas Safe registered engineers. Always ask for proper certification and paperwork.