Choosing and fitting a new boiler is a bigger decision than most homeowners realise — the wrong size, brand or type can leave you paying for a mistake for the next decade. Call 020 7183 4810 for honest, no-pressure advice and a free fixed-price survey from a Gas Safe registered, Vaillant approved installer covering Kilburn.
Thinking about a new boiler?
Free home survey, honest advice on the right size and type, fixed price before we start.
Need a Gas Safe engineer today?
Same day callouts across Central and West London, fixed quotes and fully guaranteed work.
This guide covers how to think about a boiler replacement — which type suits your household, what affects the price, and why the installation itself is worth getting right first time.
Which boiler type actually suits your home
- Combi boiler. The right fit for most flats and smaller households: instant hot water, no tank, no cylinder. Struggles a little if two bathrooms run at once.
- System boiler with a cylinder. Better for larger homes or higher hot-water demand, since it stores hot water ready to use at multiple outlets simultaneously.
- Conventional (heat-only) boiler. Still found in older properties with a loft tank; usually only worth keeping if the rest of the system is staying as-is.
The right choice depends on your bathrooms, household size and existing pipework — which is exactly what a proper in-person survey is for, rather than a guess from a website calculator.
Why the installation itself matters as much as the boiler you pick
| The shortcut | What actually goes wrong |
|---|---|
| “Any fitter will do, gas is gas” | Only a Gas Safe registered engineer may legally install a domestic gas boiler. An unregistered install is a criminal offence and can leave you without valid insurance if anything fails. |
| “Skip the power flush to save money” | Old sludge left in radiators circulates straight into a new boiler. It’s one of the most common reasons manufacturers refuse a warranty claim. |
| “Just size it the same as the old one” | An oversized or undersized boiler runs inefficiently and can short-cycle, wearing out components years early. Correct sizing needs an actual heat-loss and hot-water demand assessment. |
| “Reuse the old gas pipe without checking it” | A higher-output boiler can need a larger gas pipe. Skipping this check causes ignition and pressure faults that keep coming back. |
Stop and get a proper survey before you commit if…
- A quote was given without anyone visiting your home
- You can’t see a Gas Safe registration number on the quote or the fitter’s ID card
- The price doesn’t mention a power flush and magnetic filter
- You’re not sure whether a combi is actually right for your household’s hot water use
What it costs to get it wrong
A badly sized or badly installed boiler doesn’t fail quietly — it fails expensively. Warranty claims are commonly refused where a power flush wasn’t documented, leaving you paying full price for a repair that should have been covered. An undersized boiler in a family home means permanently disappointing hot water and higher bills than the efficiency rating promised.
And any work carried out by someone without Gas Safe registration risks invalidating your buildings insurance on top of the safety risk.
How Olia’s Plumbing & Heating handles it
- Survey. We assess your household’s hot water demand, existing pipework and gas supply in person.
- Fixed quote. A single, clear price for the right boiler for your home — no upselling, no surprises.
- Install. Full drain-down, power flush, magnetic filter, correctly sized pipework and a properly routed flue.
- Commission and certify. Combustion testing, Gas Safe registration and a completed Benchmark logbook so your warranty is valid.
- Handover. We walk you through your new controls before we leave.
- Gas Safe registered, Vaillant approved installer
- Manufacturer warranties of 7–12 years, properly registered
- Fixed price agreed before any work starts
- Honest advice on boiler type and size, not just the biggest sale
- Experience across period Kilburn homes and family houses
Get honest advice and a fixed price.
Free home survey across Kilburn, no obligation.
Frequently Asked Questions
How long does a boiler installation take?
A like-for-like combi swap usually takes one working day. A full conversion from a tank-and-cylinder system typically takes two to three days. Call 020 7183 4810 and we’ll confirm a timeline after a survey.
Which boiler brand should I choose?
Worcester Bosch and Vaillant are widely regarded for longevity and parts availability, while Ideal offers strong value for flats and rentals. We’ll recommend what genuinely suits your home rather than pushing one brand.
Do I need new radiators with a new boiler?
Usually not, if they’re in good condition — a proper power flush and, where needed, thermostatic radiator valves are normally enough.
Will you handle the warranty registration and paperwork?
Yes — Gas Safe notification, manufacturer warranty registration and the Benchmark logbook are all handled as part of the job.
What if I’m not sure whether to repair or replace my current boiler?
Call 020 7183 4810 and we’ll give you a straight answer on-site. If a repair is the better value option, our Boiler Repair Kilburn team can take care of it instead.
Book your boiler installation in Kilburn
Call 020 7183 4810 or request a call-back for a free, no-obligation survey.
Related services: Boiler Swap Kilburn · Combination Boiler Installations Kilburn · Boiler Service London · Boiler Repair Kilburn
Peyman
CEO & Founder — Gas Safe Registered Engineer
Peyman is the founder of Olia's Plumbing & Heating, a London based team with over 15 years of hands on experience in boiler installation and repair, central heating, gas work and emergency plumbing. He personally oversees jobs across Central and West London and writes these guides to help homeowners understand their heating systems.
- Gas Safe Registered
- 15+ years experience
- Covering all of London
