How Much Does an Electric Boiler Cost to Install in the UK?
Montgomery GordonIf you're weighing up an electric boiler, cost is usually the first question and the hardest one to pin down. Search online and you'll find figures anywhere from £1,300 to £6,000, and most of those numbers don't tell you why the range is so wide.
Here's the honest answer: installing an electric boiler in the UK typically costs between £2,000 and £4,000 all-in for a straightforward job, but the final figure depends on three things - the boiler itself, the labour to fit it, and whether your electrics can already handle it. That last one is where most of the surprises happen, and it's worth understanding before you get quotes.
What Determines the Cost of an Electric Boiler Installation
An installed price is really three separate costs added together.
The boiler unit. Prices run from around £600 for a compact model suited to a flat, up to £2,500 for a larger combi capable of heating a family home. Output (measured in kW) is the main driver - the more heat and hot water your property needs, the higher the output, and the higher the price.
Installation labour. This is where electric boilers have a genuine edge. Because there's no flue to fit, no gas supply to connect, and no Gas Safe certification required, a straightforward electric boiler swap can often be done in a matter of hours rather than a full day. Expect labour costs of roughly £500 to £2,000 depending on complexity.
Electrical work. This is the variable that catches people out, so it deserves its own section below.
On top of these, a few extras can apply depending on your setup: a hot water cylinder if you're fitting a system boiler rather than a combi, smart controls or weather compensation if you want tighter running-cost control, and safe disposal of your old boiler if you're switching away from gas or oil.
Electric Boiler Installation Cost by Property Size
As a rough guide, based on typical UK property types and the outputs they need:
| Property Type | Typical Output | Installed Cost Range |
|---|---|---|
| 1-bed flat | 6-9kW | £1,300 - £2,500 |
| 2-3 bed house | 9-12kW | £2,000 - £4,000 |
| 4+ bed house | 12-15kW+ | £3,500 - £6,000+ |
Larger homes with higher hot water demand sometimes need a higher-output unit or additional electrical capacity, which is why the top end of the range climbs. Worth flagging early: outputs up to 15kW run on a standard single-phase supply, but anything above that steps up to three-phase, which most UK homes don't have as standard - more on what that means for cost below. A proper assessment of your property is the only way to know where you'll land - which is exactly why we quote individually rather than publishing a single fixed price.
Why Electric Boilers Are Often Cheaper to Install Than Gas
A gas boiler installation is a bigger job by nature. It needs a Gas Safe registered engineer, a flue routed through an external wall, and a live gas connection - and if your property isn't already on the gas grid, connecting it can cost thousands before the boiler even goes in.
An electric boiler sidesteps all of that. No flue, no gas pipework, no combustion to certify. It fits directly into your existing wet system, so your radiators and pipework stay as they are - only the heat source changes. That's a large part of why electric boilers are increasingly the default choice for flats, off-grid properties, and any home where running a flue or gas supply would be difficult or expensive.
The Cost Homeowners Often Miss: Electrical Upgrades
This is the part most online guides skate over, and it's worth being precise about, because the numbers vary more sharply than people expect.
The ECA Arceus range runs from 6kW up to 27kW, and the electrical supply it needs scales with output:
| Output | Supply Type | Nominal Current | Circuit Breaker |
|---|---|---|---|
| 6kW | Single-phase | 26A | B32 |
| 9kW | Single-phase | 39A | B40 |
| 12kW | Single-phase | 52A | B63 |
| 15kW | Single-phase | 65A | B80 |
| 18kW | Three-phase only | 26A | B32 (3-phase) |
| 24kW | Three-phase only | 35A | B40 (3-phase) |
| 27kW | Three-phase only | 39A | B40 (3-phase) |
Two things stand out here. First, the largest single-phase model (15kW) needs an 80A dedicated circuit breaker - a serious chunk of most UK homes' total incoming supply, which is commonly rated at 60-100A overall. Second, everything from 18kW upward is three-phase only.
Most UK homes only have a single-phase electricity supply, so if your property's heat demand calls for an 18kW-plus output, you're not just looking at a consumer unit upgrade - you may need to apply to your local electricity network operator to bring a three-phase supply to the property, which is a different (and often slower and costlier) process than an electrician swapping a consumer unit. This is the scenario behind the £2,000-£8,000 upper end of the electrical cost range.
On top of the circuit itself, the supply must be protected by a residual current device (RCD) with 30mA tripping sensitivity, and the cable feeding the boiler needs to be sized correctly for the model - anywhere from 6mm² up to 10mm² depending on output and phase.
This is the single biggest reason two "electric boiler installation" quotes for what looks like the same job can be thousands of pounds apart. It's not the boiler - it's what's behind the wall, and how well the output has been matched to what your property actually needs. The fix is straightforward: get your electrics assessed and your heat demand properly calculated as part of your quote, before you commit to an output, so there are no surprises once the work starts.
What to Expect on Installation Day
A few practical points worth knowing before the engineers arrive. The Arceus units weigh between 26kg and 29kg depending on output, so they're carried and mounted by two installers rather than one. The boiler itself needs clearance around it once it's on the wall - roughly 500mm above, 250mm below, and 150mm either side - so there's room to service it later without a fight.
Your installer will also complete a Benchmark Commissioning Checklist as part of the job. This is a standard industry record confirming the boiler was installed and commissioned to the manufacturer's instructions, and it's what gets used to notify Building Control that the installation complies with Building Regulations - either directly or through the installer's Competent Persons Scheme membership, which is how ECA's own engineers self-certify. It isn't an extra cost on top of your quote; it's just part of what a properly completed installation includes, and you should be left with a copy for your records.
What About Running Costs?
Installation is only half the picture. On a standard electricity tariff, a typical 2-3 bed home running a 12kW electric combi should budget roughly £1,200 to £1,800 a year for heating and hot water - more than a comparable gas boiler on unit price alone, though that gap narrows once you factor in the running-cost difference against no annual gas safety check requirement. Electric boilers don't need one, unlike a gas appliance. We'd still recommend an annual service to keep things running efficiently and to keep the manufacturer's warranty valid, but it's a simpler visit without the legal certification a Gas Safe check involves. Pair the boiler with solar PV, and running costs can fall by 40 to 60%. We've covered this in full in our guide to electric boiler running costs, including a breakdown by property type.
Are There Grants for Electric Boiler Installation?
Worth being upfront about this one: current UK schemes like ECO4 and the Boiler Upgrade Scheme are aimed at heat pumps and gas boiler replacements, not electric boilers specifically, so there's little in the way of direct government funding to offset the cost. What you do get instead is lower ongoing overheads - no annual gas safety check, no flue maintenance, and a simpler system with fewer parts to go wrong.
Electric Boiler Installation Costs in London
If you're in London, expect installation costs to sit toward the upper end of the national range. Labour rates in the capital typically run 15 to 30% above the UK average, which affects the fitting cost regardless of which boiler you choose.
That's exactly why it pays to get your supply and installation from the same team. ECA UK installs across North and East London - South Woodford, Wanstead, Walthamstow, Leyton, Leytonstone, Ilford, Chingford, Woodford Green, Redbridge and the surrounding areas - using our own Gas Safe registered engineers, with no subcontractors. We supply and fit the full ECA Arceus electric boiler range, and you're welcome to see the boilers in person at our showroom at 12 Raven Road, South Woodford, London E18 1HB before you commit.
How to Get an Accurate Quote
- Get in touch - call or send us your details. Knowing your number of bedrooms, bathrooms and radiators helps us advise quickly.
- Free quote - we'll recommend the right boiler and output for your property and give you a clear, no-obligation price, including any electrical work needed.
- Installation - our Gas Safe engineers fit and commission your new boiler, and leave everything clean and working.
- Aftercare - registration, paperwork, and support if you need us afterwards.
FAQs
How much does an electric boiler cost to install in the UK?
Most straightforward installations cost between £2,000 and £4,000 all-in, covering the boiler unit and labour. Larger properties, or those needing electrical upgrades, can run higher - up to £6,000 or more.
Is electric boiler installation cheaper than gas?
Often, yes, for the fitting itself - there's no flue, no gas connection, and no Gas Safe certification required, so labour costs and installation time are typically lower. Running costs work the other way, with electricity costing more per unit than gas.
Do I need an electrical upgrade for an electric boiler?
Possibly. Boilers up to 15kW need a dedicated circuit on a standard single-phase supply, and if your consumer unit can't handle that load, you'll need an upgrade - typically £450 to £950 for a straightforward consumer unit swap. Outputs of 18kW and above need a three-phase supply, which most UK homes don't have as standard and may need to be arranged with your local electricity network operator. We assess this as part of every quote.
Do I need a three-phase electricity supply for an electric boiler?
Only for larger outputs. The ECA Arceus range runs on a standard single-phase supply up to 15kW, which covers most flats and houses up to around 4 bedrooms. 18kW and above requires three-phase. We'll help you calculate your property's heat demand before you commit to an output, so you know which category you're in before you get a quote.
Are there grants available for electric boiler installation?
Not directly. Current schemes like ECO4 and the Boiler Upgrade Scheme focus on heat pumps and gas boiler replacements rather than electric boilers.
How long does electric boiler installation take?
A straightforward like-for-like swap is typically completed in a few hours to a day. Jobs involving electrical upgrades or relocating the boiler take longer - we'll confirm the timescale when we quote.
Do you install electric boilers in London?
Yes. We install across North and East London, including South Woodford, Wanstead, Walthamstow, Leyton, Leytonstone, Ilford, Chingford, Woodford Green and Redbridge, using our own Gas Safe registered engineers.
Get Your Free Installation Quote
The only way to know exactly what your installation will cost is a proper assessment of your property and your electrics - which is why we quote individually rather than publishing a single fixed price.
Call 0800 640 9988 (Mon-Sat, 9am-5pm), email info@uk-eca.com, or visit our showroom at 12 Raven Road, South Woodford, London E18 1HB. Prefer us to call you? Send us your details and we'll come back to you promptly.
