When we often recommend an upgrade
- Long pipe runs (boiler far from meter)
- Old skinny pipework feeding a higher-output combi
- Multiple gas appliances on the same supply
- Homes where hot water demand is high (busy mornings, big shower)
Will my gas pipes support a new combi boiler?
This is the bit that makes quotes jump.
If you’ve been quoted one price, then someone mentions “gas pipe upgrade” and everything shifts — you’re not imagining it. In London homes (especially terraces, conversions and flats), the boiler choice is only half the story. The gas supply feeding it is the other half… and it’s the half most “cheap quotes” skip.
We’re ARA Services Ltd — Gas Safe engineers based in Forest Gate (E7). We’re usually moving around Woodgrange Road, Romford Road, the A12 corridor and into North/East. Want a straight answer? Call +44 7727 154 746. Phone first. No finance plans. No scripts.
Gas Safe checks
Combi upgrades
Real London installs
Quick answer (so you don’t have to scroll)
Sometimes your existing gas pipework is fine. But if it’s undersized for a modern combi (or the run is long / the route is awkward), the boiler can struggle under load — which can show up as poor hot water performance, nuisance lockouts, or the boiler not reaching its proper output safely.
When it’s often okay
- Short run from meter to boiler
- Sensible boiler size for the property
- Pipework in good condition and correctly routed
- We can test and confirm safe working pressures
This page is about gas supply specifically. For the bigger installation picture, start here: boiler installation done properly.
What “gas pipe sizing” actually means (no waffle)
A combi boiler can demand a lot of gas when it’s producing hot water at full whack. If the pipe feeding it is too small for the distance and demand, you can get excessive pressure drop. That’s not “nice-to-have” territory — it’s safety and performance territory.
What we check (the proper way)
We look at the route, length, existing pipe sizes, and what else is on the line. Then we test as part of the installation process — because guessing is how bad installs happen.
If you’re collecting quotes, this is why some pricing looks too good to be true: why cheap boiler quotes fall apart.
What it can look like in real homes
In terraces and conversions, we often see gas runs that snake around kitchen units, go through boxed sections, or jump between floors in ways nobody wants to open up. It’s not “bad” — it’s just London housing doing London housing.
If you’re in a flat and the meter location is miles away, this becomes even more important to price properly.
Does this affect cost?
Yes, sometimes. Not because the pipe itself is gold — because access is the job. Lifting floorboards, chasing walls, working around finished kitchens, keeping it neat and compliant… that’s the time.
For how this shows up in quotes, use: our install cost breakdown.
A real moment: the “brand new combi” that still felt weak
This one sticks with me because the customer did everything “right”. They chose a solid brand. New boiler. Fresh start. But the hot water felt… underwhelming. Not awful — just not what you’d expect after spending that kind of money.
We checked the setup and found the gas supply was basically the bottleneck. Nothing dramatic, no horror story, just a run that wasn’t suited to the demand. Under load, it couldn’t comfortably deliver what the boiler wanted. Fixing the supply meant the boiler could actually behave like the boiler it was meant to be.
That’s why we push this topic. Not to sell pipework — to stop you paying for a premium boiler and getting “meh” performance.
If you’re choosing between Worcester, Vaillant and Ideal, that’s a separate decision:
brand comparison guide.
But even the best boiler can’t outsmart a starved supply.
How we handle it during an install (without making your house a building site)
A good install isn’t “rip it all out and hope”. It’s: plan the route, keep it tidy, protect finishes, and do the checks properly. If an upgrade is needed, we explain the “why” in normal language and keep the work proportionate.
Photo-first sanity check
If you don’t want a full survey yet, you can send photos: boiler location, meter position (if accessible), and any visible gas run. It’s not perfect, but it can stop wasted visits and fantasy quotes.
We size the boiler sensibly
Oversizing a boiler “just in case” can create its own problems. It can also push gas demand higher than the supply comfortably supports. The right boiler size matters (a lot).
If you’re doing that decision now: choose the right boiler size for your home .
We don’t ignore the system around it
Gas supply is one piece. System cleanliness, protection, commissioning and controls decide whether your new boiler is quiet, efficient and reliable.
If you’re worried about sludge/dirty water, this is the clean answer page: power flush: when it’s needed vs not.
Fastest way to know: 2 minutes on the phone
Call +44 7727 154 746. If you’re near Forest Gate Station, Woodgrange Park, or stuck in traffic by the A12 and just want a clear answer, tell us where the boiler is and roughly where the meter is — that alone usually gives us a strong first view.
Call — will it support it?
Not a talker? Send photos here: message your boiler + meter area.
What customers actually care about
People don’t leave reviews saying “the pipe sizing was excellent”. They leave reviews when the engineer turns up, explains things clearly, fixes the problem, and doesn’t leave a mess.
“My boiler went wrong… they fitted a new one, worked straight through, and cleaned up properly afterwards.”
Alison Louis“Identified the issues immediately and fixed the problem. Very professional.”
Rachel Boston“Reliable, honest and true to their quote — highly recommended.”
Elimelech HalberstamIf you’re mid-quote and trying to avoid “extras later”, call +44 7727 154 746 and we’ll tell you what usually changes the price on installs like yours.
Gas pipe sizing FAQ (real questions, no fluff)
How do I know if my gas pipe is too small for a new combi boiler?
The clean answer is: you confirm by proper checks as part of a Gas Safe installation process. But the clues are usually the setup: long runs from meter to boiler, older skinny pipework, and higher-output combis. If you tell us where the boiler is and where the meter is, we can usually give you a sensible first view on the phone.
Why does this matter if the boiler “still works”?
Because “works” and “works properly under load” aren’t the same thing. A combi can appear fine until hot water demand ramps up. Under-supply can lead to weak performance and nuisance issues — and it can push the installer into cutting corners to make it behave.
Is a gas pipe upgrade always expensive?
Not always. The pipe itself isn’t the cost — access is. If the route is straightforward, it can be sensible. If it involves lifting finished flooring, chasing walls, or working around a kitchen that someone paid serious money for, that’s when labour and time become the factor.
Does boiler brand change gas demand?
The brand matters for reliability and warranty support, but gas demand is more about boiler output and how the system is set up. If you’re comparing Worcester vs Vaillant vs Ideal, use: our brand comparison.
Can I get an accurate quote without a full survey?
Yes — often a realistic range is possible from photos and the right info. If you want the quickest route, follow this: how to get an accurate boiler quote without wasting time .
If my boiler is struggling, is it always the gas pipe?
No. Sometimes it’s system cleanliness, controls, or a failing component. If you’re seeing faults or inconsistent heating, start here: boiler repairs & diagnosis. We’d rather fix what’s actually wrong than push a replacement you don’t need.