London's Trusted Boiler & Heating Specialists
Premium boiler installations, fast repairs and gas servicing across London carried out by Gas Safe engineers, backed by up to a 10-year warranty and same-day emergency cover.
- Gas Safe Registered
- Fully Insured
- Up to 10-Year Warranty
Get Your Fixed Boiler Price
in Under 90 Seconds
No pushy sales calls. No home visit needed to start. Answer a few quick questions and we'll send a tailored, no-obligation quote.
Boiler Quote Builder
Fast, free & tailored to your home
Why homeowners trust us
Prefer to talk it through?
Our team is standing by to help you get the right boiler for your home.
Call our team07534 652448Heating you can trust,
done properly the first time
We combine manufacturer-grade expertise with a genuinely premium customer experience from first call to aftercare.
Gas Safe & Accredited
Every engineer is Gas Safe registered and manufacturer-trained by Baxi and Vaillant, so your installation is certified, compliant and safe.
Up to 10-Year Warranty
We fit market-leading boilers with extended manufacturer warranties, plus our own workmanship guarantee for total peace of mind.
Fast, Reliable Response
Same-day emergency callouts and rapid installs across London. When your heating fails, we're the team that actually turns up.
Transparent Fixed Pricing
Clear, upfront quotes with no hidden extras. What we quote is what you pay with finance options to spread the cost.
Rated 4.9★ by Locals
Hundreds of five-star reviews from London homeowners, landlords and estate agents who trust us with their properties.
Tidy & Respectful
We treat your home like our own dust sheets down, work areas cleaned, and everything explained before we leave.
Complete boiler, heating & gas services
One trusted team for everything from a new boiler to an emergency leak across every London borough.
Boiler Installations
New combi, system and regular boiler installs from Baxi & Vaillant usually completed in a day.
Get a quoteBoiler Repairs
Fast diagnosis and repair of breakdowns, leaks, pressure loss and error faults same-day where possible.
Book a repairGas Certificates (CP12)
Landlord gas safety certificates and appliance checks booked quickly and issued the same day.
Arrange nowPower Flush
Remove sludge and restore circulation for warmer radiators, lower bills and a longer boiler life.
Learn moreCentral Heating
Full system design, radiator upgrades, smart controls and underfloor heating from specialists.
ExploreGas Leak Detection
Urgent leak detection and made-safe callouts. If you smell gas, we respond fast day or night.
Emergency helpA simple, five-step journey
From first enquiry to lifetime aftercare clear, calm and completely hassle-free.
Enquiry
Get an instant online quote or call us we'll understand your needs in minutes.
Survey
A free, no-pressure survey (in person or by photo) to confirm the perfect solution.
Install / Repair
Gas Safe engineers complete the work cleanly and efficiently, often in a single day.
Testing
Full commissioning, safety checks and certification and we walk you through it all.
Aftercare
Warranty registration, servicing reminders and a team that's always a call away.
Our Customer Reviews On Google
Diamond Gas replaced our old boiler with a new Vaillant in a single day. Spotless work, clearly explained, and cheaper than two other quotes. Genuinely faultless.
Read moreBoiler died on a Sunday with a newborn in the house. They came out same day, diagnosed it and had us back up and running within hours. Absolute lifesavers.
Read moreAs a landlord with 9 properties I need reliable engineers. Gas certs are always done on time and their reporting is brilliant. My go-to team in London.
Read moreReal installs, real transformations
A snapshot of recent boiler and heating work across London.
Vaillant Combi Swap
Whitechapel · 1-day install
Full System Upgrade
Bow · 8 radiators + smart controls
Emergency Leak Fix
Stepney · Same-day callout
Baxi System Boiler
Canary Wharf · Flat conversion
Power Flush + Radiators
Mile End · Restored circulation
No Hot Water Fault
Poplar · Diagnosed & fixed
Before
After
Tap & Sink Replacement
London · Complete upgrade
Covering every London borough
Based in Stepney, we serve homeowners and businesses right across the capital. Your local Gas Safe engineer is never far away.
Credentials you can count on
Heating advice from the experts
Your questions, answered
Everything you need to know about boilers, pricing and our service.
A new combi boiler installation in London typically ranges from £1,900 to £3,500, depending on the brand, boiler size and how complex the installation is. Use our instant quote tool above for a tailored, no-obligation price in under 90 seconds.
Yes — absolutely. Every Diamond Gas engineer is Gas Safe registered, fully insured and manufacturer-accredited by Baxi and Vaillant. We're happy to show our registration on arrival.
Yes. We offer same-day emergency callouts across London for boiler breakdowns, no heating, no hot water and suspected gas leaks. Call 07534 652448 and we'll prioritise you.
New installations come with up to a 10-year manufacturer warranty on Baxi and Vaillant units, plus our own workmanship guarantee. We register the warranty for you so you're covered from day one.
Most standard boiler swaps are completed within a single day. After your survey we can often install within 24–48 hours — sooner in an emergency.
Yes — we offer flexible finance options so you can spread the cost of a new boiler into affordable monthly payments. Ask our team for details when you request your quote.
Ready for warmth you can rely on?
Join hundreds of London homeowners who chose Diamond Gas. Get your free, fixed-price quote today no obligation, no pressure.