COST GUIDES
What does immersion heater replacement cost in 2026?
Updated 07/26
Is your immersion heater failing to heat water properly, or not at all? It could be time for a replacement, or it could be a simpler fix than you think.
Fast Facts
Full immersion heater replacement (unit + labour): £300 on average
Heater element replacement (part + labour): £180 on average
Immersion heater repairs: £50 per hour on average for a plumber
But before you spend money on a new unit, it's worth knowing whether you need a full tank swap or just a new element - because the price difference could be significant.
In this guide, we'll cover the average immersion heater replacement cost in the UK, including element replacement, full unit costs, repair costs, and running costs.
Immersion heater replacement costs
| Cost provided item | Low cost | High cost | Average cost |
|---|---|---|---|
| Immersion heater replacement cost | £150 | £255 | £200 |
| Immersion heater element replacement cost | £130 | £230 | £180 |
| High-power immersion heater replacement cost | £170 | £325 | £250 |
| Draining of hot water cylinder | £50 | £85 | £70 |
| Replacement thermostat | £20 | £50 | £35 |
| Total immersion heater replacement cost (including hot water cylinder draining & replacement termostat) | £220 | £390 | £300 |
| Total high-power immersion heater replacement cost (including hot water cylinder draining & replacement termostat) | £240 | £460 | £355 |
| Last updated: July 2026 Our costs are ballpark averages - get a local tradesperson to quote now | |||
Replacing an immersion heater costs an average of £300 altogether, including the new heater, labour costs, and other new parts such as a replacement thermostat.
That figure bumps up to an average of £355 to replace a high-power immersion heater.
However, depending on the issue with your heater, it may be possible to save money by just replacing certain parts.
Bear in mind, too, that labour rates vary by region. Expect to pay more in London and the South East. For an accurate quote for your job, request a quote from a local plumber.
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Immersion heater element replacement cost
Replacing just the heating element costs an average of £180 all in, covering both materials and labour.
If your immersion heater isn't working properly, check the element first before assuming you need a whole new unit. Heating elements burn out over time and are much cheaper to fix.
You can buy a new element and have a plumber or heating engineer fit it. (See our guide to plumber costs for current labour rates.)
If the element is a screw-in type, some confident DIYers fit it themselves, but you'll need to partially drain the tank first. It's generally best to hire a plumber to do it for you.
Immersion heater tank replacement cost
To replace the heater tank, assuming it's an unvented hot water cylinder, you're looking at costs of around £50 plus labour.
The cost of replacing an immersion heater tank depends on its size, whether it's copper or titanium, and how easy it is to access.
Remember: you can replace the immersion heater itself without replacing your whole water cylinder.
See our guide to unvented hot water cylinder costs for more details.
Immersion heater repair cost
Not every immersion heater problem needs a full replacement. A plumber or heating engineer can often diagnose and fix faults for less.
Plumbers in the UK charge an average of £60 per hour for tasks like immersion heater repairs. You may need to fork out for replacement parts, too.
If the unit is more than 10–15 years old, a full replacement is usually better value than repeated repairs.
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Get an estimated quote for your immersion heater
Use the Checkatrade job estimate tool for a rough idea of how much your task will cost you. Type out a few details, and let the calculator dig into our data to give you a tailored estimate.
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Immersion heater running costs
An immersion heater is one of the more expensive ways to heat water. A standard 3kW element costs roughly 78p per hour to run at the unit rate of 26p per kWh (correct as of 1 July 2026).
Heating a full tank (120 litres) typically takes 2–3 hours, costing around £1.56–£2.34 each time you heat it up.
Tips to keep running costs down
Use a timer so the heater only runs when you need hot water
Insulate the hot water cylinder with a jacket
Avoid leaving it on 24/7 - this will cost more and there aren't really any benefits to doing so
Note: Electricity rates change regularly. Check your tariff and the current energy price cap for current figures.
Should you replace your immersion heater, or upgrade to a different system?
If your immersion heater is old or expensive to run, it may be worth considering alternatives.
Immersion heaters are one of the most expensive ways to heat water - so even though replacing the system is an investment, you'll spend less money on energy day to day.
You may consider:
Installing a new boiler, such as a combi boiler
Check the cost of gas vs electric water heaters to learn more about these options in more detail.
You can also check solar hot water system costs if you're considering a renewable option.
Getting quotes for each option is the best way to compare. A heating engineer can assess which is right for your property.
Find a plumber to replace your immersion heater
Finding a plumber or heating engineer to tackle your immersion heater replacement is easy with Checkatrade. We check and verify all of our members, so you know the tradespeople in our directory meet our standards.
Enter your postcode to get started, and browse tradespeople who offer immersion heater replacement and repair in your area.
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You can also use our quick and easy request a quote feature and we will get experienced local plumbers and heating engineers to contact you directly.
To get accurate quotes, be as detailed as you can:
Note whether you need an element replacement or a full unit swap
Tell them the make and model of your existing unit if you know it
Let them know the size of your hot water cylinder
Mention whether the unit is easy to access or in a tight airing cupboard
Describe any symptoms: no hot water, lukewarm water, a tripped circuit breaker
Or, download the Checkatrade app!
Immersion heater cost checklist
Use this checklist to make sure you've covered the main cost factors before getting quotes.
Your immersion heater replacement cost checklist
FAQs
It's usually a relatively quick job, taking less than half a day. The exact timing does depend on things such as ease of access to the unit and whether there are any unforeseen issues, however.
A plumber or heating engineer fits the replacement unit in most cases. If there's an electrical fault affecting the unit, that's when you may also need an electrician. See our guide to electrician hourly rates for what to budget if electrical work is needed.
Only if you're very confident. Replacing a screw-in heating element is a job some competent DIYers tackle, provided they know how to isolate the electricity supply and partially drain the tank.
The full unit is a different matter, however. Incorrect installation can cause leaks, electrical faults, or void your home insurance - so you should hire a plumber.
A plumber or heating engineer typically charges around £200 to replace an immersion heater in the UK, including labour and basic costs. All in, including things like a new thermostat, you're looking at a total bill of about £300.
Most immersion heaters last 10–20 years. The heating element may need replacing sooner, however - typically every 5–10 years depending on water hardness. In hard water areas, limescale buildup can shorten its life considerably.
The most common signs are:
water that won't heat up fully
lukewarm water at the tap
a tripped circuit breaker on the immersion circuit
a burning smell near the unit
A plumber can test the element with a multimeter to confirm if it's failed.
If the cylinder and tank are in good condition, yes. Replacing the element is usually much cheaper than a full unit replacement. If the unit is old or the cylinder is also failing, on the other hand, a full replacement makes more sense.
No. Leaving it on 24/7 wastes energy heating water you won't use, and costs significantly more. Use a timer set to heat water 30–60 minutes before you need it.
Most modern immersion heaters have a built-in thermostat, so they won't overheat, but they will keep cycling on to maintain the temperature.
Need any help planning your central heating? From costs and maintenance tips to user guides and tips for being economical, we know you want a job done right.
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