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A new boiler is a job where the right choice, a legal install and a properly prepared system matter as much as the appliance itself — especially in Blackheath’s older, conservation-sensitive homes. These are verified heating engineers covering Blackheath, each checked before listing.
✅ Checked before listing — identity, insurance, trading presence, Gas Safe (where relevant).
✅ Workmanship guarantee badges on listings — 1, 3, 6 or 12 months
⚠️ Smell gas or suspect a gas leak? Do not operate electrical switches or use flames; ventilate and turn off the gas only if safe; leave and call the National Gas Emergency Service on 0800 111 999. CO alarm or suspected carbon monoxide? Stop appliances if safe, ventilate, leave immediately, call 0800 111 999 from outside, do not re-enter until the emergency service says it is safe, and seek immediate medical advice. Call 999 if anyone has serious symptoms or has collapsed. Gas & CO safety →
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Coverage: Blackheath and around — centred on SE3 (Blackheath Village, the Heath, Blackheath Park, Vanbrugh Park), with cross-borough streets into the Greenwich side and the Lee edge. Blackheath spans Lewisham and Royal Greenwich, so confirm your postcode and borough for tenant or landlord routing.
What this covers: supplying and fitting a new domestic gas boiler — choosing the type, the legal Building Regulations install, flue positioning, and preparing the system — by a Gas Safe registered engineer.
Not sure it’s this you need? A boiler that’s faulty rather than beyond repair is on Boiler Repair; keeping an existing boiler healthy is on Boiler Servicing; cold radiators or a sludged system on Central Heating Repair.
Costs: indicative ranges are under What it costs below — editorial estimates only.
Availability: each engineer sets their own hours, shown on their profile.
Choosing the right boiler for the property
The best boiler for a home depends on the building, not the brochure — and Blackheath’s mix of large period houses, converted flats and estate homes means there’s no single answer. A combi heats water on demand with no cylinder, which suits smaller homes and flats with one bathroom and limited space. A system boiler works with a hot-water cylinder and copes better with higher demand — several bathrooms drawing at once, which is common in Blackheath’s larger Victorian and Georgian houses. A regular (heat-only) boiler keeps the traditional tank-and-cylinder arrangement, and many older Blackheath homes still run one.
Switching type — say, a regular system to a combi — is a bigger job than a like-for-like swap, because it changes how hot water is delivered and often means removing tanks and re-running pipework. A verified engineer should size the boiler to the home’s heat demand and hot-water needs rather than fitting whatever’s on offer; our Combi vs System Boiler guide helps you weigh it up. If you’re considering a lower-carbon route, an air-source heat pump is a different option with its own government grant support and suitability checks — worth raising with your engineer.
What the law requires
Installing a boiler isn’t just a plumbing job — it’s notifiable building work, and cutting corners here causes real problems when you come to sell.
A Gas Safe registered engineer. Only an appropriately qualified Gas Safe registered engineer may install a gas boiler; the Gas Safe Register is the official list of those legally allowed to do it. Ask to see the Gas Safe ID card and check the engineer’s unique seven-digit licence number and relevant work categories before work starts.
Building Regulations notification. A boiler is a heat-producing appliance and the installation must comply with the applicable gas-safety and Building Regulations requirements. For an ordinary non-higher-risk building, Gas Safe Register explains the usual competent-person route: an appropriately registered engineer notifies the installation through Gas Safe, the scheme notification is made to the local authority, and a Building Regulations Compliance Certificate is normally sent to the property within 10–15 working days after notification. For competent-person scheme work in a higher-risk building, GOV.UK confirms that the relevant notice or certificate must be sent to the Building Safety Regulator rather than the local authority, and the installer should confirm that the scheme provider covers higher-risk-building work. Higher-risk-building work that is neither exempt nor competent-person scheme work generally requires Building Safety Regulator approval before it starts. For non-higher-risk work where self-certification is not used, approval must follow the applicable local-authority or registered-building-control-approver route. Keep the certificate or other completion evidence with the property records.
Boiler Plus and Approved Document L. Under the ordinary route for installing or replacing a gas-fired wet-heating boiler in an existing dwelling, the boiler should meet at least 92% ErP seasonal efficiency and have appropriate time and temperature controls. Approved Document L includes an exceptional-circumstances route using SEDBUK 2009 minimum efficiencies of 78% for natural gas and 80% for LPG. Oil-fired boilers are subject to separate efficiency provisions. The additional efficiency measure applies specifically to a gas-fired combination boiler installed in an existing dwelling and may be flue-gas heat recovery, weather compensation, load compensation or a qualifying smart control.
Carbon-monoxide warning. Requirement J3 of Schedule 1 to the Building Regulations requires appropriate provision to detect and warn of carbon monoxide when a fixed combustion appliance is installed in a dwelling. For a new or replacement fixed gas-burning appliance other than one used solely for cooking, the Approved Document J route is a carbon-monoxide alarm complying with BS EN 50291-1:2018 in the same room, positioned in accordance with paragraphs 3.43–3.45 and the manufacturer’s instructions.
Commissioning and warranty. On completion you should receive the relevant commissioning and compliance records. A manufacturer warranty may require registration, servicing or other evidence within specified times, but the requirements and consequences depend on the particular product terms and are separate from statutory consumer rights.
The flue question — the part conservation rules reach
Every new boiler needs a compliant flue route, and its position is not a free choice in Blackheath. The Planning Portal explains that, for a house in a conservation area, a flue on a highway-facing principal or side elevation will not normally fall within the relevant householder permitted-development rights, so planning permission may be required. Flats and maisonettes cannot rely on those householder rights, so the proposed work must be checked with the local planning authority. Historic England explains that Listed Building Consent is required where the work affects the building’s special architectural or historic character. Confirm the position with the local planning authority before the flue route is fixed.
In practice, that shapes where the boiler can go. A verified engineer who works in Blackheath plans the flue route with those constraints in mind before quoting — a boiler positioned for a tidy flue on a rear elevation is very different from one that would force a terminal onto a protected street frontage.
Preparing the system — the step that protects a new boiler
A new boiler should not be connected to a contaminated system without appropriate preparation. Approved Document L’s ordinary installation route calls for central-heating and primary-hot-water circuits to be thoroughly cleaned and flushed before the new heating appliance is installed, with suitable inhibitor and commissioning. BS 7593:2019+A1:2024 gives the detailed system-water recommendations, including cleaning method, inhibitor and in-line filtration. The particular method — including whether powerflushing is justified — depends on the system condition and instructions.
Blackheath adds a second reason to prepare the domestic-hot-water side correctly: Thames Water confirms that the region’s water is hard. Under the ordinary Approved Document L route, suitable measures should be taken for feed water to water heaters and for the domestic-hot-water circuit of combination boilers in hard-water areas. That is not a universal requirement to fit a scale-treatment device to every boiler primary heat exchanger. The chosen measure should match the appliance, system and manufacturer’s instructions.
Safety first
If you smell gas or suspect a leak, follow the National Gas Emergency Service steps in order:
1. Don’t switch anything electrical on or off, don’t use a naked flame, and don’t smoke.
2. Open doors and windows if it’s safe to do so.
3. If the meter control handle is safely reachable, turn the gas off at the meter — unless the meter is in a cellar.
4. Leave the property.
5. Call the National Gas Emergency Service on 0800 111 999. Do not go back into the property until the National Gas Emergency Service or attending emergency services advise that it is safe.
A correctly installed boiler is the first defence against carbon monoxide. London Fire Brigade says CO can come from faulty, badly fitted or poorly maintained fuel-burning appliances, or blocked flues and vents, and recommends an audible CO alarm rather than a colour-change indicator. If a CO alarm sounds or CO is suspected, leave immediately, call 999 if anyone has serious symptoms or has collapsed, and always seek immediate medical advice stating that CO exposure is suspected. Call 0800 111 999 before returning and do not re-enter until advised that it is safe. After a new install, keep to the applicable servicing and safety-check schedule; see Boiler Servicing.
Landlords, leaseholders and council tenants
Private landlords. Where Regulation 36 applies — generally where residential accommodation is occupied under a lease shorter than seven years or under a licence — HSE requires the landlord to arrange the required gas-safety checks on relevant landlord-provided appliances and flues, including the first check within the applicable period after installation and annual checks thereafter. Existing tenants must receive the record within 28 days of the check, and prospective tenants must receive a current record before occupation. Regulation 36(3)(c), as amended in 2018, requires each record to be retained until two further safety checks of that appliance or flue have been carried out. If the appliance or flue is removed, the last record must be retained for two years from the date of its last check.
Leaseholders. A boiler inside your flat is normally yours to arrange, but a new flue, condensate route or external pipework can affect the building’s fabric and shared elements — check your lease and tell your managing agent or freeholder before work that touches outside walls, especially on a conservation-area or listed block.
Lewisham council tenant. A boiler replacement isn’t a private booking. Lewisham carries out gas heating and hot-water work through its specialist contractors — report it through the council rather than arranging your own install. Royal Greenwich council tenant (Greenwich-side) should follow Royal Greenwich’s route; confirm your borough by postcode.
What a boiler installation costs
A rough orientation for boiler installation in Blackheath, to sense-check a quote — not a price list.
| Job | Typical indicative range | Notes |
|---|---|---|
| Like-for-like combi swap | £1,800–£3,000 | Similar position; includes controls and filter |
| System or regular boiler replacement | £2,200–£3,800 | With cylinder; varies by size and layout |
| Regular-to-combi conversion | £3,000–£4,500+ | Removing tanks, re-piping, added labour |
| System flush + filter at install | £300–£600 | Pre-install clean; protects the new boiler |
Editorial estimate only — not regulated rates, market data or a cost survey. Actual quotes vary by boiler make and output, boiler type, flue and pipe routing, system condition and access. Blackheath is inside the London ULEZ. A van up to and including 3.5 tonnes that is driven within the ULEZ on a ULEZ operating day, does not meet the applicable emissions standard and is not exempt or covered by a valid discount or grace period is subject to the £12.50 daily charge. ULEZ operates every day except Christmas Day (25 December); heavier vehicles are governed separately by the London LEZ. Rules can change, so check the current position.
Why verified plumbers
A boiler installation is safety-critical and legally regulated, and compliance records may be needed later for a sale, building-control evidence or a warranty claim. Every heating engineer listed for Blackheath is verified for identity, insurance and trading presence before going live and re-checked annually, with Gas Safe registration confirmed directly where gas work is involved — you should still ask to see the ID card. You contact the engineer directly: no lead fee, no per-enquiry charge, and no pay-to-play ranking, with any Sponsored placement labelled. Listings show a workmanship-guarantee badge of 1, 3, 6 or 12 months.
Frequently asked questions
Under the usual Gas Safe competent-person route for a non-higher-risk building, the registered engineer notifies the installation and the Building Regulations Compliance Certificate is normally sent within 10–15 working days after notification. For competent-person scheme work in a higher-risk building, the relevant notice or certificate goes to the Building Safety Regulator rather than the local authority; work outside the competent-person or exempt routes generally requires BSR approval before it starts. Other lawful building-control routes and completion evidence apply according to the building and work. The system must be properly commissioned and the applicable commissioning information supplied; the Benchmark checklist is a commonly used way to evidence commissioning, not a universally mandatory statutory certificate. Keep the records because they may appear in property searches or be requested by a conveyancer, buyer or lender, but a Building Regulations Compliance Certificate is not a universal legal prerequisite to sell or remortgage a home.
Under the ordinary Approved Document L route, a gas-fired wet-heating boiler installed or replaced in an existing dwelling should meet at least 92% ErP seasonal efficiency and have appropriate time and temperature controls. An exceptional-circumstances route uses SEDBUK 2009 minimums of 78% for natural gas and 80% for LPG. The additional efficiency measure applies to gas-fired combination boilers installed in existing dwellings; oil-boiler standards are separate.
It should be prepared before the new appliance is installed. Approved Document L calls for the relevant circuits to be thoroughly cleaned and flushed and treated with suitable inhibitor under the ordinary route; BS 7593:2019+A1:2024 gives the detailed preparation and maintenance recommendations. Whether a particular warranty requires additional evidence is product-specific.
On a house in a conservation area, a flue on a highway-facing principal or side elevation will not normally fall within householder permitted-development rights, so planning permission may be required. Flats and maisonettes cannot rely on those householder rights. For a listed building, Listed Building Consent is required where the work affects its special architectural or historic character. Confirm the route with the local planning authority before choosing the boiler or flue position.
Usually yes, but it’s a bigger job — tanks come out and pipework changes, which affects hot-water delivery. It’s worth sizing it properly for the home; see our Combi vs System guide.
No. Lewisham handles heating installs and repairs through its specialist contractors, so report it through the council rather than booking privately.
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Related areas
Verified heating engineers across Blackheath and nearby, including Lee, Hither Green, Lewisham, Kidbrooke, Greenwich, Charlton and Eltham. Browse all local coverage from the Lewisham plumbers hub.
Related services in Blackheath
Boiler Repair · Boiler Servicing · Central Heating Repair · Emergency Plumber · General Plumbing
Related guides
Combi vs System Boiler · Boiler Repair or Replace · London Hard Water Guide · Landlord Plumbing Compliance Checklist
A new boiler is only as good as the choice, installation and system behind it. Match the appliance and flue to the property, prepare the system correctly and keep the compliance records. Manufacturer warranty conditions are product-specific, so check registration, servicing and evidence requirements rather than assuming the installation alone preserves cover.
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Last reviewed: August 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 — Gas Safe Register, GOV.UK, the Health and Safety Executive, the National Gas Emergency Service, London Fire Brigade, Thames Water, Lewisham Council and the Planning Portal. Source links are provided within this page where relevant.
Sources & further reading
- Gas Safe Register — Building Regulations certificates
- Gas Safe Register — official register of gas engineers (check the engineer’s unique seven-digit licence number and work categories on the ID card)
- GOV.UK — Boiler Plus factsheet– GOV.UK — Approved Document L, Volume 1 (existing-dwelling efficiency, controls, exceptional route and system preparation)- GOV.UK — Building regulations approval (competent-person and building-control-body routes); changes to the building-control process (scheme notices for higher-risk buildings go to the Building Safety Regulator); building-control approval for higher-risk buildings (approval route and exceptions)
- GOV.UK — Approved Document J (Requirement J3 and the standard route for a BS EN 50291-1:2018 carbon-monoxide alarm with a new or replacement fixed gas-burning appliance in a dwelling, excluding an appliance used solely for cooking)
- HSE — Gas safety: landlords and letting agents
- Planning Portal — Flue, chimney or soil and vent pipe: planning permission; Historic England — Listed Building Consent (consent is required where work affects the building’s special architectural or historic character)
- Lewisham Council — Blackheath conservation area
- Thames Water — Hard water
- London Fire Brigade — Carbon monoxide safety
- Lewisham Council — Repairs responsibilities
- BSI — BS 7593:2019+A1:2024 code of practice (central heating water treatment: cleaning/flushing, inhibitor, in-line filter, annual inhibitor testing; every five years, either re-dose or carry out a full laboratory water analysis)
- GOV.UK — Apply for the Boiler Upgrade Scheme (grants for heat pumps and biomass boilers; installer-led, MCS-certified)
- Transport for London — Ultra Low Emission Zone (£12.50 when a non-compliant in-scope vehicle is driven within the zone on a ULEZ operating day and is not exempt or covered by a valid discount or grace period; ULEZ does not operate on Christmas Day (25 December); heavier vehicles are governed separately by the London LEZ)