New Boiler Installation
Combi, system and regular boilers supplied and fitted by Gas Safe registered engineers — old unit taken away, new one commissioned, warranty registered and the paperwork sent to you.
Gas Safe registered · London & surrounding areas
Most people call us because the old boiler has finally given up, or because the repair bills have started adding up. We come and look at the actual property — how many bathrooms, what pressure comes off the mains, where the flue can go — and tell you what will work in your home rather than what happens to be in the van.
You get a written, fixed price before anything is touched. It covers the boiler, the fitting, the parts and the certificates, so the figure you agree to is the figure you pay unless you ask us to change the job.
Like-for-like swaps, conversions from a system boiler to a combi, back boiler removals and moving the boiler to another wall are all standard work for us. If a conversion is not right for the property, we will say so before you spend the money.
What’s included
- Supply and fit of your new boiler
- Removal and disposal of the old boiler and any redundant tanks
- System cleaned and a magnetic filter fitted to protect the new boiler
- All gas, water and condensate pipework the installation needs
- Controls set up — room thermostat or smart control, wired or wireless
- Commissioning, gas safety checks and a proper handover
- Manufacturer warranty registered in your name
- Building Regulations notified and your compliance certificate issued
How long it takes
- Straight combi swap
- Usually one day
- System or regular boiler swap
- One to two days
- Conversion to a combi
- Two to three days
- Back boiler removal
- Two to three days
Typical durations for an average London property. We confirm yours at the survey, along with a fixed written price.
Why two quotes for the same boiler differ by a thousand pounds
The appliance is rarely where the difference sits. Two installers quoting the same Worcester or Vaillant model are buying it at broadly similar money, and neither is making the difference back on the box. What separates the quotes is everything around it: whether the gas supply from the meter is being upgraded, whether the flue is being rerouted or reused, whether the system is being cleaned properly and with what, whether the old cylinder and loft tanks are being removed and the resulting holes made good, and whether the controls are the ones that came in the carton or ones chosen for the house.
A cheap quote is usually not a cheaper installer. It is the same job with items removed, and the removed items are the ones that decide whether the appliance lasts its warranty. The way to compare two quotes honestly is to lay them side by side and ask which of those seven things each one includes — not to compare the totals.
Sizing: the calculation that should be in your quote and usually is not
Boiler output is chosen from the heat loss of the building: its volume, its construction, its glazing, its insulation and the temperature you want to hold on the coldest day. It is not chosen from the output of the boiler being replaced, which was itself often a guess, and it is not chosen from the number of bedrooms.
Oversizing is the more common error and the more expensive one. A boiler with far more output than the house needs reaches temperature quickly, shuts down, cools, and fires again — cycling on and off all day. Every one of those cycles wears the ignition and the fan, and the boiler spends most of its life outside the condensing range where its efficiency actually lives. A correctly sized boiler runs longer and gentler at a lower flow temperature, which is where the efficiency figure on the label comes from in the first place.
The separate question is hot water, and it is answered by the flow rate of your incoming main and the number of outlets used at once, not by the heating calculation. Those are two different numbers and a quote that mentions neither has not been calculated at all.
The gas supply from the meter is the part people never think about
A modern combi boiler asks more of the gas supply than the appliance it replaces, particularly on hot water. If the pipe from the meter is undersized or long, or if it has been extended for a hob and a fire over the years, the boiler will be starved at exactly the moment it is working hardest. The symptom is a boiler that locks out on high demand and behaves impeccably during a service visit.
This is measured, not estimated: a working gas pressure reading at the appliance with everything running. If the drop is beyond what the standard allows, the supply pipe has to be upgraded, and finding that out at the survey rather than on the second cold morning is the difference between a fixed price and an argument.
What moves the price on a job like this
We give a fixed written price after the survey. These are the things that make one quote differ from another for what looks like the same work.
- Whether the boiler stays where it is
- Moving it to another room means new gas, flow and return, condensate and electrics, plus a new flue penetration and making good the old one.
- The flue route
- A straight run through an outside wall is simple. A run through a roof, up a chimney with a liner, or anywhere needing access equipment is not.
- Removing a cylinder and loft tanks
- You gain a cupboard and a loft, but the pipework has to be capped back properly and the openings made good — that is joinery and plastering, not plumbing.
- The gas supply from the meter
- If the working pressure drop is outside the permitted range, the supply pipe has to be upgraded before the boiler will run reliably.
- How the system is cleaned
- A chemical clean and a power flush are different pieces of work. On old pipework the manufacturer's warranty usually depends on the second.
- Controls
- The controls in the box are the minimum. Zoning a house, or fitting weather compensation, costs more and saves more.
How it works
- 01
Free survey
We come and look at the job, check the gas supply, mains pressure and flue route, and talk through what you actually need.
- 02
Fixed written price
The price comes in writing with the boiler make, model and warranty spelled out. No obligation to go ahead.
- 03
Installation
Floors covered, old unit out, new one in and commissioned. Most swaps are finished and running the same day.
- 04
Handover and paperwork
We show you the controls, register the warranty and send your Building Regulations certificate.
Questions we get asked
Which boiler should I get?
It depends on the property, not on the brand. One bathroom and decent mains pressure usually points to a combi; several bathrooms running at once normally wants a system boiler and a cylinder. We tell you which fits your home and why.
Do you take the old boiler away?
Yes. The old boiler goes with us, along with any redundant loft tanks if we are removing them, and is disposed of properly. Nothing is left for you to deal with.
How long is the warranty?
It depends on the manufacturer and the model — typically somewhere between five and twelve years on the boilers we fit. We register it in your name so it is valid from day one.
Will I be without heating and hot water?
Only for the working day in almost every case. A straight swap goes off in the morning and is back on the same evening.
Do I need Building Regulations paperwork?
Yes — fitting a boiler is notifiable work. We notify it and your certificate follows automatically. You will want it when you come to sell the property.
Guides on this topic
Where this comes up in London
Where a replacement gets interesting in London is the interwar belt — Harrow, Hillingdon, Barnet and Enfield — where a great many houses still run a back boiler behind the fireplace or a boiler chosen for a house half the size the extension made it. Those are survey jobs, not questionnaire jobs, which is exactly why the fixed-price national firms decline them.
Other things we do
- Full Central HeatingComplete heating systems fitted from scratch: boiler, pipework, radiators, controls and commissioning.
- Megaflo & Unvented SystemsHigh-pressure hot water for busy homes. Unvented cylinder installation, servicing and G3 certification.
- Power FlushingSludge and debris removed from your system so radiators heat evenly again and your boiler stops working overtime.
- Under Floor HeatingWet underfloor heating zoned, balanced and pressure-tested before the screed goes down — on its own or alongside radiators.
- Boiler Service & BreakdownsAnnual servicing to keep your warranty valid, plus fast fault-finding and repairs when the heating goes down.
Get in touch
Fastest way to reach us is a call or WhatsApp — send a photo of the job and we will come back with a price. Prefer email? Use the form and we will reply as soon as we are off site.