Want to know how much it costs to install an immersion heater? In this article, we’ll look at how much you might pay in labour, supply, and total costs for an immersion heater. This guide will also delve into further relevant topics such as what the installation work involves and whether you can do it DIY.
This article will prove very useful if you’re planning to have a new immersion heater fitted. Immersion heaters are popular primarily because they can provide a backup supply of heated water through immersion water heating. Further, with an immersion heater timer, you can set it to warm up at whatever time you choose.
Let’s start by taking a look at the average price of fitting an immersion heater based on the size and type. The average cost to install an 11” immersion heater made of copper is £65 to £179. Should it be 14”, expect to pay £66 to £180, or £68 to £180 for a 27” heater installation.
When it comes to incoloy heaters, the installation cost will land around £67 to £182 for an 11” heater, £73 to £189 for a 14” heater, or £74 to £191 for a 27” heater.
As for a titanium immersion heater, it will cost roughly £77 to £191 for an 11” heater, £80 to £200 for a 14” product, or £75 to £280 should it be a 27” heater.
On average, a heating engineer charges about £50-80 an hour, though it will depend on a range of different factors. For the specific jobs mentioned above, the price may range from £50 to £160, assuming that the work lasts for one to two hours. In some cases, a contractor will charge a set labour fee.
Moving on to material costs, the 11” copper immersion heater cost is approximately £15 to £19. If it’s 14”, expect the supply costs to land around £16 to £20, or £18 to £20 if it's 27”.
As for incoloy immersion heaters, you’d pay about £17 to £22 for an 11” product, £23 to £29 if it was 14”, or £24 to £31 if it's 27”.
Looking at titanium immersion heaters, they cost about £27 to £31 for an 11” heater, £30 to £40 for a 14” heater, or £25 to £120 for a 27” heater.
If you’d rather install an immersion heater DIY, to buy the tools and materials needed for an installation, it would cost about £3-9 for an immersion spanner, £2-8 a bottle for WD40, £2 to £40 for a hammer, £0.30 to £0.50 a pack of PTFE tape, and £7-20 for a small screwdriver.
There are a variety of factors that can impact on the cost of fitting an electric immersion heater. Firstly, the costs will vary depending on whether the heater is single element, double element, or triple element.
Beyond that, ease of access and the location of your property are also relevant. The reason that property location matters is due to how labour rates differ throughout the nation with prices highest in the southeast and London particularly but lower in the north of England, Scotland, and Northern Ireland.
| Type of Heater | Size | Labour Cost | Supply Cost | Total Installation Cost |
|---|---|---|---|---|
| Copper | 11" | £50 to £160 | £15 to £19 | £65 to £179 |
| 14" | £50 to £160 | £16 to £20 | £66 to £180 | |
| 27" | £50 to £160 | £18 to £20 | £68 to £180 | |
| Incolony | 11" | £50 to £160 | £17 to £22 | £67 to £182 |
| 14" | £50 to £160 | £23 to £29 | £73 to £189 | |
| 27" | £50 to £160 | £24 to £31 | £74 to £191 | |
| Titanium | 11" | £50 to £160 | £27 to £31 | £77 to £191 |
| 14" | £50 to £160 | £30 to £40 | £80 to £200 | |
| 27" | £50 to £160 | £25 to £120 | £75 to £280 |
Let’s take a closer look at what sort of immersion heaters are available based on material. In this section, we’ll discuss their features, costs, and pros & cons.
The cheapest option is generally a copper immersion heater with a supply cost of approximately £15 to £20. They are best suited to soft and natural water areas like a domestic hot water cylinder.
They are fairly inexpensive to install, whether you hire a professional or not. Copper immersion heaters are relatively easy to fit, thus labour costs can be lower than with other heaters, particularly if it takes an hour or less.
However, these heaters are incompatible with thermal store units, stainless steel tanks, and unvented cylinders. Combining copper with stainless steel can lead to corrosion of the copper elements, which is expensive to repair.
✔ Relatively inexpensive among immersion heater prices
✔ Well suited to natural and soft water areas
✔ Can be installed quickly
✖ Incompatible with some materials
✖ Expensive to repair if combined with stainless steel tanks.
These immersion heaters consist of a variety of superalloys. These are suited to soft water and hard water areas.
They cost about £17 to £31 to buy before installation. Incoloy immersion heaters are well suited to hard water areas given that they’re very resistant to corrosion.
However, they are not suitable for very hard water areas like the east and south of England since they cannot handle too high of a water intake pressure.
On the other hand, they are designed to manage high-temperatures as well as being highly durable and oxidation-resistant.
✔ Suitable for soft and hard water areas
✔ Highly resistant to corrosion
✔ Durable
✔ Oxidation-resistant
✖ More expensive than a copper immersion heater
✖ Not suited to very hard water regions
Next on the list we have a titanium immersion heater. These heaters are generally the highest quality option, but with that, they have a high price tag, usually ranging from £27 to £120 in supply costs alone.
They tend to be employed in hard water areas. These heaters are very durable and long-lasting, especially due to the fact that they can manage boiling hot temperatures.
They are a low-maintenance option, provide great value for money, and are not prone to accumulating limescale.
✔ Premium choice
✔ Best option for hard water areas
✔ Low-maintenance
✔ Do not suffer with limescale build-up easily
✖ Expensive
In this section, we’ll break down the steps involved in having a new immersion heater installed. We’ll also take on some added costs that you may incur.
Unless you decide to fit the heater by yourself, the first step involves choosing and hiring a heating engineer/company.
You should obtain at least three quotes before making a decision. When contacting a trader/company, it is advisable to ask for some prior references and what their previous experience is, to ensure that you’re hiring the right person for the job. Once you’ve made a decision, go ahead and make a booking.
On the day of the installation, the heating engineer will proceed with the job by isolating the consumer unit circuit that is relevant, in order to disconnect the power to the immersion heater. This ensures that the existing immersion heater is safe to remove.
Failure to isolate an electrical application before removing it can be extremely dangerous and can result in death, thus this step is a vital safety measure.
Then, it’s time to test the system for power. An electrical test meter can be used to ensure that there is no power reaching the unit.
Once this is confirmed, the heating engineer will remove the electrical wiring before taking a look at the time thermostat. Assuming that the thermostat is fine, the element should be tested for continuity should the meter show a high level of resistance.
In this case, it would mean that the element is open circuit and thus the heater is not functioning correctly.
Once these tests have been complete, the tank should be drained through the gate vale. Alternatively, this could be achieved by switching off the main water supply.

As soon as the cold water is no longer entering the tank, the labourer will be free to fit a hosepipe to the drain plug that is located at the bottom part of the tank. This will fully clear the water from the tank.
After the tank has been fully drained, the old immersion heater needs to be disconnected from its cables and wiring. Using WD40 can make removing the heater a lot easier when applied to the nut and tank.
Once you’ve removed the old heater, it should be replaced with an immersion heater of the right size. It should be wrapped in PTFT tape as this will secure the heater in place and ensure its durability.
Lastly, the taps and drain plugs must be tightened while the cylinder is refilled, the thermostat is rewired and then set to the correct temperature.
Next, the heating engineer will undertake tests to make sure that the immersion heater is working correctly. This includes testing the immersion heater switch.
There are various added jobs you may wish to pay for after having your new immersion heater fitted. For instance, to have tests undertaken and then acquire an electrical safety certificate would cost approximately £80 to £200, depending on the size of your property.
Want a new central heating system? You can expect to pay somewhere in the range of £3500 to £6000, again depending on the size of your home.
Most of the time, it’s fairly easy to install a new immersion heater DIY. However, you should only do so if you know what is involved and you feel okay with basic electrical work and using basic hand tools.
It is essential that you turn off the power before working on an installation (as laid out in the previous section).
It’s vital that you follow all the necessary safety precautions. For extra security, you should buy electricity resistant gloves. That said, if you have any doubts, hire a professional.
It’s important that prior to replacing an immersion heater element, you check that the issue is not relating to the consumer unit.
If it is, then you’ll need the help of a contractor. However, if the problem is only with the immersion heater, then you’ll save around £50 to £160 in labour costs if you fit the immersion heater DIY.
It’s important that your work complies with Approved Document G of the Building Regulations, if you are located in England or Wales.
However, the regulations can differ in Scotland and Northern Ireland. As for planning permission, it’s very unlikely that approval will be needed, unless you intend to perform extensive works that somehow alter the structure of the property.
In most cases, a professional will not need to sign off on this type of work. As for safety, the main risks associated with replacing an immersion heater is that of electrocution, which can be fatal.
So once again it cannot be understated how essential it is to take the necessary safety precautions. Beyond that, there’s a risk of harming yourself with the tools/equipment used. Of course, there is also the issue of an incorrect installation which could prove costly, especially if the instalment resulted in damage to the heater itself.
As with any installation work, there are some downsides worth noting. Firstly, there is always a small chance of an incorrect installation.
Of course, if you’ve hired what you believe is a good contractor/company, this is very unlikely, but there’s always a small risk.
If you’ve applied for planning permission or building regulations approval and your application(s) are rejected, you’ll need to apply again.
Based on the feedback you received with your initially rejected application(s), you can adjust your proposals and apply again.
A: An immersion heater is a separate element from a boiler. It’s a device that can be fitted to an immersion heater tank or container in order to heat up a liquid for purposes of heating a home.
A: On average, about two and a half hours, though it will depend on the volume of liquid that needs to be heated up.
A: On average, a replacement costs approximately £100 to £130.
A: This will depend on the kilowatt-rating of the heater but on average it costs about £0.15 per kW. For instance, a 4kW immersion heater may cost about £0.60 per kW to operate.
A: On average, immersion heaters are more expensive to run than using gas heating, costing about twice as much.