Do I need a special electrical supply for an electric combi boiler?

Most units need a dedicated 30A or 40A circuit on its own breaker, separate from your ring main. Smaller units (under 9kW) can sometimes run off a standard 32A circuit, but anything above that needs a sparkie to assess your consumer unit and incoming supply. If your home has an older fuse board or you're on a 60A main fuse, you may need an upgrade from your distribution network operator before installation, which is free but can take 4 to 6 weeks to arrange.

How long does an electric combi boiler last?

Typically 15 to 20 years, longer than the 10 to 15 you'd get from a gas combi. Fewer moving parts and no combustion stress on components.

Can I get the Boiler Upgrade Scheme for an electric combi boiler?

No. The £7,500 BUS grant covers heat pumps and biomass only. Electric resistance boilers are not eligible because they're considered less efficient than heat pumps, which deliver three to four times more heat per unit of electricity used.

Do electric combi boilers need annual servicing?

Servicing is optional rather than legally required, since there's no gas safety obligation. That said, we'd recommend a check every two to three years to test the element, pressure relief valve and pump. Most manufacturers require evidence of regular checks for warranty claims, so don't skip it entirely if your unit is still under cover.

Will an electric boiler work with my existing radiators?

Yes, in almost all cases. The radiators don't care where the hot water comes from. Same goes for thermostats, TRVs and most heating controls.

Electric Combi Boiler 2026: Is It Right for Your Home?

Electric Combi Boiler 2026: Is It Right for Your Home? | Eco Home Check

What Is an Electric Combi Boiler and How Does It Work?

An electric combi boiler heats water using an internal element, the same way a kettle does, then sends it to your radiators and hot taps. No gas. No flue. No combustion at all.

That's the whole technology in two sentences.

A gas combi burns natural gas to heat a heat exchanger, which warms the water flowing through it. An electric combi skips the burning bit entirely. Electricity passes through a resistive element submerged in the water tank, the element gets hot, the water gets hot, and a pump pushes it around your system. It's closer to a giant immersion heater with a clever control board than to a traditional boiler.

The practical upshot. No gas pipe needed. No annual gas safety certificate. No carbon monoxide risk. No flue cutting through your wall. See our guide on alternative heating technologies for more detail.

What you do need is a decent electrical supply, usually a dedicated 30A or 40A circuit on its own breaker, and ideally a hot water cylinder or thermal store if more than one person in the house wants a shower in the morning. Pure instantaneous electric combis exist, but they struggle to deliver high flow rates because heating water on demand with electricity is genuinely demanding on the supply.

Most units sit in a kitchen cupboard or utility room. They're quiet. They don't smell. And because there's no combustion, they last longer than gas boilers on average, often 15 to 20 years versus 10 to 15 for gas.

Electric vs Gas Combi Boiler: Which Should You Choose in 2026?

Gas wins on running cost. Electric wins on installation flexibility, carbon emissions and maintenance.

Here's the honest bit. If your home is already on mains gas and you've got a working flue and pipework, an electric combi is almost never the cheaper option to run. Electricity in the UK currently sits around 27p per kWh on a standard tariff. Gas is around 7p. Even with an electric boiler running at near-100% efficiency and a gas boiler at 90%, you're paying roughly three to four times more per unit of heat delivered.

But running cost isn't the only factor.

Factor	Gas combi	Electric combi
Unit cost	£900 to £2,500	£1,500 to £4,000
Install cost	£1,800 to £3,500	£500 to £1,500
Annual running cost (3-bed)	£900 to £1,400	£2,200 to £3,200
Efficiency	90 to 94%	99 to 100%
Lifespan	10 to 15 years	15 to 20 years
Annual service	Required	Optional
Carbon emissions	High	Low (lower still on green tariff)
BUS grant eligible	No	No

So when does electric actually make sense?

When you're off the gas grid. See our guide on carbon emissions for more detail. When you're in a flat where a flue is impossible. When you're future-proofing against gas being phased out. When the property is a holiday home used six weeks a year and the running cost differential barely matters. Or when you simply cannot face the £4,000 to £6,000 quote you've just had for a new gas boiler installation including pipework and flue relocation.

We see a lot of confused homeowners assume an electric boiler must be the "greener" choice and therefore the right one. It's greener, yes. Cheaper to run, no. Both things can be true.

How Much Does an Electric Combi Boiler Cost to Install and Run?

Expect £2,000 to £5,500 fitted, and roughly £2,200 to £3,200 a year to run in a typical three-bedroom home.

Let's break that down properly because the install side is where most quotes either look suspiciously cheap or suspiciously expensive.

The boiler unit itself runs from around £1,500 for a basic Heatrae Sadia Electromax or EHC Comet up to £4,000 for higher-output units from Elnur or Trianco. Mid-range, you're looking at £2,000 to £2,800 for a 12kW unit, which suits most flats and small houses.

Installation is where electric wins. No flue. No gas pipe. No gas safe engineer needed, just a competent electrician and a heating engineer working together (or one person qualified in both). Typical install runs £500 to £1,500 if your existing radiator system and cold water feed are usable. If you're starting from scratch with new pipework, add £1,500 to £3,000.

Running costs depend almost entirely on your electricity tariff and how well-insulated the house is. The maths:

A 12kW electric boiler running for 4 hours a day in winter uses roughly 48 kWh. At 27p per kWh, that's £12.96 a day, or about £390 a month during heating season. Across a full year including summer hot water, you're typically £2,200 to £3,200 for a small-to-medium home.

But here's where it gets interesting. If you pair an electric boiler with an Economy 7 or Octopus Go tariff and a hot water cylinder, you can heat your water overnight at around 9p to 12p per kWh. That can knock 30 to 40% off your annual bill if you set it up properly. Add solar panels and a battery storage system and the picture changes again.

This is the only realistic way to make an electric combi competitive on running cost. Without it, you're paying the price of convenience.

The other hidden cost most guides skip. Insulation. If you're switching to electric heating, you cannot afford to be heating a leaky house. A poorly insulated three-bed will eat electricity at a rate that makes the bills genuinely painful. Before you change boiler type, check what insulation grants you might qualify for.

Which Homes Are Best Suited to an Electric Combi Boiler?

Flats without gas connections, small off-grid properties, and well-insulated homes already on cheap overnight electricity tariffs.

In practice we see four clear cases where an electric combi is the right choice.

First, flats. Particularly upper-floor flats in older buildings where running a new flue through three storeys of brickwork is either impossible or costs more than the boiler itself. A friend of ours in a top-floor Edinburgh tenement spent two years getting nowhere with gas combi quotes before fitting electric and saving herself the planning headache entirely.

Second, rural off-grid properties. If you're currently on oil or LPG and an air source heat pump isn't viable because of property type, ground conditions or budget, electric is the next cleanest option. It's not cheap to run, but it's predictable, low-maintenance and doesn't require an annual tanker delivery.

Third, small homes. One-bed flats, park homes, annexes, granny flats, anywhere you've got modest hot water demand and a smaller heated area. The running cost gap with gas matters less when you're only heating 50 square metres.

Fourth, anyone serious about decarbonising and willing to pair the boiler with solar PV, battery storage and a time-of-use tariff. This is the genuine future-proof setup. Done right, your boiler is effectively running on stored solar and overnight cheap-rate electricity, and the per-unit cost drops to something that competes with gas.

What electric combis are not suited to. Large four or five-bedroom family homes on mains gas with multiple bathrooms. Anywhere with three teenagers and a power shower habit. Properties with poor insulation and an EPC of E or below, switching to electric here is essentially setting fire to money.

If your home falls in that last category, the priority isn't the boiler at all, it's improving the building fabric first.

Can You Get a Grant to Help Pay for an Electric Boiler?

No. There's no government grant currently available for standard electric combi boilers.

This catches a lot of people out, so let's be precise about what is and isn't covered.

The Boiler Upgrade Scheme pays £7,500 towards air source and ground source heat pumps, £5,000 for biomass and £2,500 for air-to-air heat pumps and heat batteries. Electric resistance boilers, which is what a standard electric combi is, are not on the list. The government's reasoning is that resistance heating is inefficient compared to heat pumps (which deliver 3 to 4 units of heat per unit of electricity), so it doesn't qualify as a low-carbon technology under the scheme.

ECO4 can occasionally fund electric heating replacements, but only in narrow circumstances. Usually when an existing electric system is being upgraded for a household on qualifying benefits, and only if a heat pump genuinely isn't viable. It's not a route most people will be eligible for. The full eligibility detail sits in our ECO4 guide, but the short version is that you need to be on means-tested benefits and the installer needs to demonstrate why an alternative isn't possible.

Warm Homes: Local Grant varies by council and a small number of authorities do fund electric heating upgrades, particularly in flats and off-grid homes. Cornwall, parts of Scotland and a handful of London boroughs have included electric in their offers. Check what your council currently funds through our eligibility checker rather than guessing.

Here's what most guides won't tell you. If you're being pushed toward an electric combi by an installer claiming there's a grant available, walk away. There isn't, not for a standard electric boiler. Anyone telling you otherwise is either confused or selling.

The genuine grant-funded route for someone wanting to move off gas is a heat pump via the Boiler Upgrade Scheme. The £7,500 brings the typical install cost down to £4,000 to £6,000, which is comparable to a like-for-like electric combi install once you factor in the running cost savings over 15 years.

Top Electric Combi Boilers Available in the UK Right Now

The market is smaller than gas, but four brands cover most installs: Heatrae Sadia, EHC, Elnur and Trianco.

We're not going to pretend there's a vast field of options here, because there isn't. Electric combis are a niche product and most installers stick to a handful of trusted units.

Heatrae Sadia Electromax. The Marmite of the electric boiler world. Compact, reliable and made by a brand most plumbers already know from their unvented cylinders. The Electromax is technically a system boiler with built-in cylinder, popular in flats and small houses. Around £2,400 to £2,800 for the unit. Solid choice if you've got space for the larger footprint.

EHC Comet and Fusion. Electric Heating Company is a Scottish manufacturer specialising in electric. Their Comet range is the closest you'll get to a like-for-like gas combi replacement. 9kW to 14.4kW outputs, wall-hung, modulating, and they integrate with most thermostats. Unit cost £1,800 to £2,600. We see this one specified most often in new flat developments.

Elnur Mattira. Spanish-made, well-regarded, slightly more expensive but with better build quality and a longer warranty (some models come with 7 years versus the standard 2 to 3). Around £2,500 to £3,500.

Beyond those three, you'll also see units from Trianco, Thermaflow and Strom for specific applications, though availability and installer familiarity vary by region.

A quick word on warranties. Always check what's covered, electric boilers tend to have fewer moving parts and longer manufacturer warranties than gas, but the heating element itself is sometimes excluded or covered for a shorter period. Read the small print before you sign.

And before you commit to any specific unit, get three quotes from MCS or NICEIC-certified installers. The boiler is half the cost, the install is the other half, and a bad install ruins a good boiler. If you want a wider view of how electric stacks up against alternatives for your home, our central heating systems guide covers the full range of upgrade options including hybrid setups.

The honest summary. Electric combi boilers are a good answer to a specific question. If that question is "I'm in a flat, I haven't got gas and I don't want a heat pump", then yes, fit one. If the question is "how do I cut my heating bills", the answer is almost always either keeping your gas boiler and improving insulation, or going for a heat pump with the BUS grant. Don't let anyone tell you electric is a money-saver. It isn't. It's a convenience-saver, and sometimes that's worth paying for.