New boiler cost
Boiler quotations vary widely, and usually not because of the boiler. This page sets out what actually moves the price, so you can read two quotations and understand why they differ.
Why there is no price list here
We do not publish boiler prices, because a genuinely honest range would be too wide to help you and a narrow one would be invented. What follows is the thing a price list cannot give you: the factors that make one property's job cost twice another's, so you can judge a quotation on its merits.
The twelve things that move the price
Roughly in the order they tend to matter. A quotation that is much higher or much lower than another usually differs on two or three of these rather than on all of them.
- Boiler type
- Combi, system and regular boilers are not priced alike, and the type also determines what else has to change — a cylinder removed, tanks taken out, pipework reconfigured.
- Output and specification
- A boiler sized for a four-bedroom house with two bathrooms costs more than one sized for a flat. Within a range, higher outputs and longer warranties both carry a premium.
- Like for like, or a change of type
- Replacing a combi with a combi in the same position is the shortest job there is. Converting from a regular boiler to a combi means removing a cylinder and tanks and reworking pipework.
- Moving the boiler
- Relocating an appliance means new gas, water and heating pipework, a new flue route and a new condensate run — often the single biggest addition to a quotation.
- Flue arrangements
- A short horizontal flue through an external wall is straightforward. Vertical flues, long runs and routes through voids that must stay inspectable all add work.
- Condensate drainage
- A nearby internal drain is simple. Where the run has to go outside, it needs to be correctly sized, insulated and protected against freezing.
- Gas supply pipework
- The supply has to deliver enough gas at the right pressure. Long runs, undersized existing pipework or a higher-output appliance can mean an upgrade back towards the meter.
- System condition and cleaning
- An old, sludged system needs proper chemical cleaning before a new appliance goes on it. Skipping that is how new boilers fail early and warranties are refused.
- Cylinder changes
- Where a cylinder is being replaced, upgraded to unvented, or removed entirely, that is a substantial piece of work in its own right.
- Controls
- Reusing an old programmer costs nothing and works no better than it did. Modern programmable and load-compensating controls cost more and materially affect running cost.
- Access and making good
- Loft installations, tight cupboards, boarded floors and tiled walls all take time. So does putting things back properly afterwards.
- Timing
- An emergency replacement in a cold snap is a different job from one planned for a quiet week in September, and it is priced accordingly.
How to compare two quotations fairly
Put them side by side and check each of the following appears in both. Where one is missing an item, that is usually the whole explanation for the difference.
- the make, model and output of the boiler, not just "a new combi";
- system cleaning, and what kind — a chemical flush is not a drain-down;
- a magnetic filter, fitted rather than offered as an extra;
- inhibitor dosed into the system;
- controls: what is being fitted, or whether existing ones are being reused;
- any pipework, gas supply or flue alterations;
- removal and disposal of the old appliance, cylinder and tanks;
- making good after the work;
- the warranty length and what it is conditional on;
- whether building regulations notification and certification is included.
The false economies
Three things are commonly cut to bring a price down, and all three cost more later:
- Skipping the system clean. Debris from an old system ends up in a new heat exchanger. This is the most common cause of an early failure and of a declined warranty claim.
- Reusing tired controls. A modern boiler run by a thirty-year-old mechanical timer cannot do what it is capable of.
- Oversizing the boiler. Fitting something bigger "to be safe" makes the boiler cycle rather than run steadily, which costs money every day it operates.
Costs that come after the installation
The installed price is not the whole picture. Also worth budgeting for:
- Annual servicing, which is what keeps the warranty valid — see boiler servicing;
- Fuel, which depends far more on how the system is controlled than most people expect;
- Eventual repairs once the warranty period ends.
What about a heat pump instead?
A heat pump installation costs more up front than a boiler replacement and is a different kind of project. The reason it belongs on a cost page is that grant support applies to one and not the other: there is no Boiler Upgrade Scheme grant for a conventional gas boiler, but an eligible heat pump installation may attract one.
That does not make a heat pump cheaper in every case, and we are not going to pretend otherwise. It does mean the comparison is worth making properly if you have time to make it. See heat pump grants for the current values, and our guide comparing heat pumps and gas boilers.
Related services
Boiler replacement
When to replace rather than repair, and what the work involves.
Boiler installation
Moving a boiler, or fitting one where there was not one before.
Boiler servicing
The annual cost that keeps a manufacturer warranty valid.
Heat pump grants
Grant values that apply to heat pumps — and not to gas boilers.
Heat pump vs gas boiler
How to compare the two properly, including running costs.
Get a quote
Tell us about the property and we will come back to you with next steps.
Frequently asked questions
- Why does this page not give a price range?
- Because a range wide enough to cover every property honestly would be too wide to help you budget, and a narrower one would be a guess presented as information. What we can usefully tell you is what moves the price, so you can read a quotation properly.
- Why are two quotations for the same boiler so different?
- Almost always because of scope rather than the appliance: system cleaning, a magnetic filter, controls, pipework alterations, removal and disposal, and making good. Compare what is included before comparing totals.
- Is the cheapest quotation ever the right one?
- Sometimes — but check what has been left out. A quotation that omits system cleaning and a filter is cheaper today and more expensive over the life of the boiler, and it can put the manufacturer warranty at risk.
- Is there a grant that reduces the cost of a new boiler?
- Not through the Boiler Upgrade Scheme, which funds heat pumps rather than conventional gas boilers. If you are open to a heat pump, grant support may apply to that instead.
- Does a longer warranty justify a higher price?
- Often, but read what it depends on. Almost all manufacturer warranties require an annual service by a qualified engineer, recorded properly, and some depend on a magnetic filter being fitted at installation.
- How do I get a figure for my property?
- Someone needs to see the property, or at least know what boiler you have now, where it is, what you want instead and the state of the system. That is what a quotation is for — send us the details and we will come back to you.