Electric boilers in 2026: are they actually worth it?

Electric boilers are marketed with a confidence that does not always survive contact with a customer's energy bill. The pitch is appealing: no flue, no gas supply, no annual gas safety check, no combustion, nearly silent, small enough for a kitchen cupboard, and often described as one hundred per cent efficient.

All of that is true. And for most homes connected to mains gas, an electric boiler will still cost substantially more to run. Both things can be true at once, and understanding why is the difference between a good decision and an expensive one.

We install gas, oil, LPG and air conditioning, and we have no particular stake in which one you choose. What follows is the reasoning we would give you across the kitchen table.

What an electric boiler actually is

An electric boiler heats water using an immersion element, in the same way a kettle does. There is no flame, no flue and no combustion. Electricity goes in, heat comes out, and that heat goes to your radiators and taps exactly as it would from a gas boiler.

Because nothing goes up a chimney, essentially all of the electricity becomes heat. That is where the "one hundred per cent efficient" claim comes from, and it is accurate as far as it goes. A modern condensing gas boiler runs at roughly 90 per cent in the real world, so on that measure the electric boiler wins.

The problem is that efficiency is not the same as cost, and the two get conflated constantly.

Why they are being pushed so hard

There are real advantages, and it would be unfair to pretend otherwise.

• No flue. This is the big one. A flat with no external wall in a sensible position, or a listed building where nothing can appear on the elevation, may have no realistic gas option at all.
• No gas supply needed. Off the gas network, this removes oil deliveries or LPG tanks from the picture entirely.
• No annual gas safety check. Electric boilers still want servicing, but there is no Gas Safe requirement and no landlord CP12 for that appliance.
• Compact and quiet. Genuinely small, and near silent in use.
• Fewer things to go wrong. No burner, no heat exchanger fouling, no combustion to go out of adjustment.

For a one-bedroom flat with no gas and no flue route, an electric boiler can be the obvious and correct answer. That is a real market and it is growing.

The running cost problem, with the arithmetic

This is where the marketing goes quiet, so let us do the sum properly.

Electricity and gas are both sold by the kilowatt hour, and across recent years electricity has typically cost somewhere in the region of three to four times as much per unit as gas. The exact ratio moves with the market and your tariff, so check your own bill rather than taking anyone's word for it.

Now apply the efficiencies. An electric boiler turns one unit of electricity into one unit of heat. A gas boiler turns one unit of gas into roughly 0.9 units of heat. So the gas boiler wastes about ten per cent — but it started from fuel costing a fraction as much.

Work it through and the electric boiler typically costs somewhere around three times as much per unit of heat delivered. On a house using a substantial amount of heating across a winter, that difference is not marginal. It is the kind of gap that turns into four figures over a year in a family home.

This is the single most important thing to understand, and it is why we will talk most people on mains gas out of an electric boiler. The efficiency figure is real. It is simply swamped by the price of the fuel.

What about off-peak tariffs?

You will sometimes see electric boilers paired with a night-rate tariff. This can help, but be careful: it works properly when heat is stored — in a thermal store or a well-insulated cylinder charged overnight. An electric combi making hot water on demand at four in the afternoon pays the day rate like everybody else.

If somebody is proposing an electric boiler on the strength of a cheap night rate, ask exactly what is storing the heat. If the answer is nothing, the saving is largely theoretical.

Where they genuinely make sense

Having been discouraging, here is where we would actively recommend one.

Flats with no flue route

If there is no way to terminate a flue that meets the regulations, and no realistic prospect of freeholder consent, the comparison with gas is academic. An electric boiler is the answer because gas is not available.

Small, very well-insulated properties

If total heat demand is genuinely low — a modern one-bedroom flat with good insulation and small heat loss — then three times a small number is still a manageable number, and the simplicity and low install cost may win.

Annexes, outbuildings and garden rooms

Running a gas supply out to a garden room is expensive and often impractical. Electric heating of some form is usually the sensible choice, though for a single room air conditioning running as a heat pump will normally beat an electric boiler comfortably.

Listed buildings and conservation areas

Where a flue terminal on a visible elevation would not get consent, the flue-free option solves a planning problem that money alone cannot.

Properties off the gas network

Against oil or LPG the comparison is much closer, and factors like tank space, delivery access and the hassle of ordering fuel start to matter as much as pence per unit.

Electric boiler or heat pump?

If you have decided to heat with electricity, there is a question worth asking before you buy an electric boiler: would a heat pump be better?

Both run on electricity. The difference is that an electric boiler makes heat, while a heat pump moves it. An electric boiler gives you one unit of heat per unit of electricity. A heat pump gives you around three, because it is transporting warmth from the outside air rather than generating it from scratch.

That is a threefold difference in running cost between two electric options, which is far larger than most people expect.

The catch is that a heat pump costs considerably more to install, needs space outside, and works properly only in a house that holds its heat and has radiators sized for a cooler flow temperature. An electric boiler will work in any house; it will just cost more to run.

The rough rule: if the property suits a heat pump, a heat pump is the better electric option by a distance. If it does not, an electric boiler may be the practical choice despite the running cost.

Worth knowing: air conditioning is an air-to-air heat pump, and for heating one or two awkward rooms it is often the cheapest effective answer of the lot.

The thing installers forget: your electrical supply

An electric boiler large enough to heat a family home draws a great deal of current. Models in the 12 to 15 kilowatt range are common, and a 15 kilowatt boiler pulls roughly 65 amps on its own.

A typical domestic supply in an older property is 60 to 80 amps in total, for everything — the oven, the shower, the kettle, the car charger if you have one. Adding a large electric boiler to that can mean a supply upgrade from the distribution network operator, which is a separate job with its own cost and its own waiting list, and in some cases a consumer unit upgrade too.

This is the most common unpleasant surprise with electric boilers. Before you commit, someone should look at your existing supply, your main fuse rating and your consumer unit. If a quote does not mention any of that, it is incomplete.

Types of electric boiler

Electric combi

Heats water on demand, like a gas combi. Flow rates are usually modest compared with a gas combi of similar cost, so hot water can feel weaker. Best suited to single-bathroom properties.

Electric system boiler with a cylinder

Heats a stored cylinder. Better hot water performance, and it opens the door to charging overnight on a cheaper rate. Needs cupboard space.

Dry core and thermal storage systems

Store heat in a core or a large water store, charged overnight and released through the day. The most likely of the electric options to make financial sense on a differential tariff, but physically large and a bigger installation.

What might change the maths

There is a reasonable case that the gap will narrow. Electricity generation is decarbonising, there has been persistent policy discussion about rebalancing the levies that sit disproportionately on electricity bills, and gas will not be the default forever.

But "the sums might improve during the life of this appliance" is a weak reason to accept a threefold running cost increase today. If the relationship between gas and electricity prices changes substantially, that is the moment to reconsider — and a boiler fitted today will not be your last.

The verdict

If your home has mains gas: an electric boiler will almost certainly cost you significantly more to run, and we would talk you out of it unless there is a flue or planning reason that makes gas impossible.

If your home has no mains gas: it becomes a genuine contest against oil, LPG and heat pumps, and the right answer depends on your property, your insulation and your supply.

If your home has no flue route: electric may be the only option, and that is a perfectly good reason to choose it.

If you are choosing between electric options: look seriously at a heat pump before an electric boiler. Three times the heat per unit of electricity is not a small difference.

What we will not do is tell you an electric boiler is cheap to run because it is a hundred per cent efficient. It is efficient. That is not the same thing.

Related reading

• Combi, system or regular boiler?
• Heat pumps versus gas boilers
• New boilers and what they cost

All heating and cooling advice