A new boiler is a big purchase and a notifiable piece of gas work, so it pays to get the right boiler, properly sized, installed to the regulations by a Gas Safe registered engineer. These are plumbers and heating engineers covering the London Borough of Hillingdon for boiler installation, each checked before being listed, so you can contact one directly.

✅ Checked before listing — identity, insurance, trading presence, Gas Safe (where relevant).
How we verify →
✅ Workmanship guarantee badges on listings — 1, 3, 6 or 12 months

⚠️ Smell gas or suspect carbon monoxide? Leave it off, don’t touch any switches, open doors and windows if safe, and call the free National Gas Emergency Service on 0800 111 999 — full gas safety steps ↓

Contact verified plumbers in Hillingdon ↓

Coverage: boiler installation across Hillingdon’s UB postcodes (UB3, UB4, UB7, UB8, UB9, UB10, UB11) and HA postcodes (HA4, HA5, HA6) — Uxbridge, Hayes, West Drayton, Yiewsley, Ruislip, Northwood, Eastcote, Ickenham, Harefield and the Heathrow villages.
What this covers: new and replacement boilers — combi, system and heat-only — like-for-like swaps and conversions, controls and flue, system cleaning and filters, and the Building Regulations notification and certificate.
Not sure this is the right page? For a boiler that’s broken down, see Boiler Repair; for the annual service or a landlord gas safety check, Boiler Servicing; for cold radiators or system faults, Central Heating Repair.
Costs: indicative installation ranges are under What it costs below — editorial estimates only.
Availability: each plumber sets their own hours, shown on their individual profile.

Jump to: Choosing & installing · The rules · Safety first · Hard water & a new boiler · By district · Costs · FAQs

Choosing and installing a new boiler

The first decision is the type of boiler. A combi heats water on demand with no cylinder, which suits smaller homes and flats; a system or heat-only boiler works with a hot-water cylinder and suits homes with higher hot-water demand or more than one bathroom. Our Combi vs System guide walks through the trade-offs — but the key point is that the boiler should be sized to the home’s actual heating and hot-water demand, not simply bought bigger. An oversized boiler cycles inefficiently; an undersized one struggles. Before quoting, a good installer surveys the job — checking gas pipe sizing, the mains water flow rate, hot-water demand, the radiator and system condition, and the flue and condensate routes — because those are what decide which boiler is suitable and what work is really needed.

A good installation is more than swapping the box. It usually includes cleaning the existing system — a chemical clean, flush or power-flush depending on its condition — to clear scale and sludge, adding a chemical inhibitor and a magnetic filter to keep it clean, fitting the heating controls the regulations now require, and making sure the flue and the condensate pipe are correctly routed (a condensate run that’s exposed outside is the thing that freezes in winter). A like-for-like combi swap is often a one-day job; converting from a system boiler and cylinder to a combi takes longer because the cylinder and tanks come out and the pipework is reworked. Moving the boiler to a new position is more involved still — it can mean rerouting the flue and condensate, upgrading the gas pipe, moving electrics and making good afterwards. If you’re weighing a lower-carbon option, a heat pump is the main alternative and government grants can apply — a different installation worth exploring separately.

The rules: efficiency, controls and notification

A new boiler in England has to meet two separate sets of requirements, and a good installer handles both as a matter of course.

The first is Boiler Plus, in force since 2018. Under it, a new gas boiler must have a space-heating efficiency of at least 92% ErP, every gas and oil boiler installation must have time and temperature controls (at minimum a programmer and room thermostat), and a new combi installation must also include one of: flue gas heat recovery, weather compensation, load compensation, or smart controls with automation and optimisation, as the government’s Boiler Plus factsheet sets out.¹

The second is Building Regulations notification. A boiler is a heat-producing appliance, so the local authority has to be told. A Gas Safe registered installer who’s a member of the Competent Person Scheme can self-certify the work and notify it through Gas Safe Register within 30 days, after which you receive a Building Regulations Compliance Certificate confirming the install meets Part L (energy efficiency).² Keep that certificate safe — it matters when you sell or remortgage. At handover, the engineer should also commission the boiler properly — checking the gas rate and combustion, dosing the system inhibitor, and handing over the filter and controls — then complete the Benchmark checklist (usually needed to validate the manufacturer’s warranty, so register the warranty too) and confirm the Building Regulations notification. And if the job includes an unvented hot-water cylinder, it should be fitted by someone holding the G3 qualification under Part G.

Safety first

Installing a gas boiler is restricted by law. The Health and Safety Executive is clear that work on gas fittings in homes must be carried out by a Gas Safe registered engineer, and that it’s illegal for anyone else to do it.³ A registered engineer carries a Gas Safe ID card showing what they’re qualified for — it’s reasonable to ask to see it, and to verify them on the Gas Safe Register.

If you ever smell gas or suspect a leak, follow the steps the National Gas Emergency Service sets out:⁴

• Don’t turn any switches on or off, don’t use anything that could spark (light switches, doorbells, mobile phones), and don’t smoke or light a flame.
• Open doors and windows to ventilate, if it’s safe to do so.
• Turn the gas off at the meter control handle — unless the meter is in a cellar or basement, in which case don’t enter.
• Leave the property if the smell is strong or you feel unwell, and call the free National Gas Emergency Service on 0800 111 999 from outside or a safe place. The line is open 24 hours.
• Don’t go back inside until you’ve been told it’s safe.

A correctly installed and commissioned boiler also protects against carbon monoxide, which a poorly burning gas appliance can produce. Every home with a gas appliance should have a CO alarm that complies with BS EN 50291, sited in line with the manufacturer’s instructions — and a new install is a sensible moment to check yours is present and in date.

Hard water and a new boiler

Protecting a new boiler from scale matters more in Hillingdon than in soft-water areas. Affinity Water classes the borough’s supply as hard to very hard (varying by zone),⁵ and the Drinking Water Inspectorate classes water of 200–300 mg/l calcium carbonate as hard, with scale building up in appliances and reducing efficiency.⁶

That’s why a careful installer doesn’t just fit the boiler onto an old, scaled system. Cleaning the existing pipework and radiators — whether a chemical clean, a flush or a full power-flush, depending on the system’s condition and the manufacturer’s warranty requirements — clears scale and sludge that would otherwise be pushed into the new heat exchanger; a chemical inhibitor slows future scale and corrosion; and a magnetic filter catches debris before it reaches the boiler. Many manufacturers’ warranties require this kind of system cleaning and protection, so it’s worth confirming it’s included in the quote. Where a scale reducer or softener is fitted to protect the boiler and hot-water system, the kitchen drinking-water tap should still be left unsoftened, as covered on our Kitchen Plumbing page.

Find a verified boiler installer by district

What an installation involves varies with the housing.

Ruislip, Eastcote and Northwood (HA4, HA5, HA6) — older suburban homes, often on system or heat-only boilers with hot-water cylinders, where conversions to a combi are common: removing the cylinder and loft tanks, reworking the airing cupboard and pipework, and upgrading the controls, with loft and cupboard space to do it.

Uxbridge and central Hillingdon (UB8, UB9, UB10, UB11) — town-centre flats and flats above shops, typically on combis, where replacing or moving a boiler can depend on safe flue termination and plume position, the condensate route, balcony or external-wall rules, and freeholder or managing-agent approval before external pipework is altered; converted properties can constrain where a boiler can go.

Hayes and Yeading (UB3, UB4) — managed blocks and newer developments, some on communal or district heating with heat interface units (HIUs) or plant-room systems, where an individual boiler installer may not be the right contractor at all; others are on individual combis, and replacing one in a flat can need managing-agent sign-off.

West Drayton, Yiewsley and the Heathrow villages (UB7) — shared and let properties where landlords commission installs and need the Building Regulations and gas paperwork; newer managed developments are common too.

Harefield and the Colne Valley (UB9) — larger and rural-edge properties, some of which may be off the mains gas grid on oil or LPG, or candidates for a heat pump. For oil, LPG or a heat pump, check the installer holds the correct qualification for that system, not just ordinary mains-gas registration.

For listed installers’ availability, check each profile.

What boiler installation costs

A rough orientation for boiler installation in Hillingdon, to sense-check a quote — not a price list.

Editorial estimate only. These figures are not regulated rates, not market data and not a published cost survey — they’re a general guide and actual quotes vary by the boiler, the system and access. The Building Regulations notification and certificate are normally handled by a Gas Safe registered installer as part of the job.

Travel charges: Hillingdon is inside the London Ultra Low Emission Zone (ULEZ), which Hillingdon Council confirms applies across all London boroughs at £12.50 a day for non-compliant vehicles, so an engineer’s van may carry that cost.⁷ Hillingdon is outside the central London Congestion Charge zone, so a Hillingdon job doesn’t normally attract the Congestion Charge unless the route also runs into central London. ULEZ rules and charges can change, so check the current position.

Frequently asked questions

Why verified plumbers — not a general directory

A new boiler is a major spend and a piece of notifiable gas work, so it pays to use someone qualified and straight with you — who’ll survey and size the boiler to your home rather than upsell, protect the system properly in a hard-water area, and handle the Building Regulations notification and paperwork as part of the job.

Every listing is checked before going live and re-verified annually: we confirm the business is legitimately trading and verify the named contact, we check evidence of public liability insurance, and — for gas and boiler work — we check Gas Safe registration, alongside confirming the engineer covers Hillingdon’s UB and HA postcodes before a profile is approved. We also keep an eye on customer feedback gathered from across the web, and you can verify any gas engineer yourself on the Gas Safe Register.

Listed plumbers pay a flat monthly fee to be listed. What that fee never buys is the verification itself — every listing is checked on the same terms — and there’s no per-enquiry middleman fee, so your enquiry goes directly to the engineer. Profiles may be suspended or removed if credentials lapse or credible concerns are raised; see the full verification process →.

Related areas

Verified plumbers across Hillingdon’s neighbourhoods, including:

• Belmore
• Botwell
• Charville
• Colham
• Cowley
• Eastcote
• Harefield
• Harlington
• Harmondsworth
• Hayes
• Hayes End
• Hayes Town
• Heathrow Villages
• Hillingdon
• Hillingdon Heath
• Ickenham
• Longford
• North Hillingdon
• Northwood
• Northwood Hills
• Pinkwell
• Ruislip
• Ruislip Gardens
• Ruislip Manor
• Sipson
• South Harefield
• South Ruislip
• Stockley Park
• Uxbridge
• Uxbridge Moor
• West Drayton
• West Ruislip
• Wood End
• Yeading
• Yiewsley

Related services

Other verified plumbing services in Hillingdon:

• Emergency Plumber in Hillingdon
• Burst Pipes in Hillingdon
• Leak Detection in Hillingdon
• Blocked Drains in Hillingdon
• Toilet Repairs in Hillingdon
• Tap Repair & Installation in Hillingdon
• General Plumbing in Hillingdon
• Bathroom Plumbing in Hillingdon
• Kitchen Plumbing in Hillingdon
• Washing Machine & Dishwasher Installation in Hillingdon
• Boiler Repair in Hillingdon
• Boiler Servicing in Hillingdon
• Central Heating Repair in Hillingdon
• Commercial Plumbing in Hillingdon

Related guides

• Combi vs System Boiler — Which Is Right for You?
• Boiler Repair or Replace?
• London Hard Water — The Complete Homeowner & Landlord Guide 2026
• London Plumbing Costs & Compliance Guide 2026

A new boiler is worth getting right first time — the correct type and size, the controls Boiler Plus requires, the system properly cleaned and protected against this borough’s hard water, and the Building Regulations notification done so you have the certificate. A verified Gas Safe engineer can survey the job, advise on the right boiler and handle the whole installation, paperwork included.

Contact verified plumbers in Hillingdon ↑

← Back to all plumbing services in Hillingdon

Last reviewed: May 2026 by Adiel Khan — SFEDI-accredited business advisor, 20+ years’ experience (South East Enterprise Ltd) and operator of VerifiedPlumbers. LinkedIn ↗

This page is checked for compliance and regulatory accuracy against the bodies cited on it — the UK Government (Boiler Plus), Gas Safe Register, the Health and Safety Executive, the National Gas Emergency Service, Affinity Water, the Drinking Water Inspectorate and Hillingdon Council. Source links are provided within this page where relevant.

Sources & further reading

1. UK Government — Boiler Plus factsheet (new gas boilers in England: minimum 92% ErP, time and temperature controls, and a combi must include one additional efficiency measure)
2. Gas Safe Register — Building Regulations certificate (a Gas Safe registered installer self-certifies and notifies within 30 days; homeowner receives a Building Regulations Compliance Certificate for Part L)
3. Health and Safety Executive — Gas safety (work on gas fittings must be carried out by a Gas Safe registered engineer; it is illegal for anyone else to do it)
4. National Gas — Emergency contacts (what to do if you smell gas; National Gas Emergency Service 0800 111 999; signs of carbon monoxide)
5. Affinity Water — Water hardness (Affinity supply classed as hard to very hard; varies by zone)
6. Drinking Water Inspectorate — Water hardness (hard = 200–300 mg/l CaCO₃; scale reduces appliance efficiency)
7. Hillingdon Council — Ultra Low Emission Zone (ULEZ covers all London boroughs including Hillingdon; £12.50 daily)