COST GUIDES
How much does an unvented hot water cylinder cost? (2026)
Updated 06/26
An unvented hot water cylinder (also called a pressurised hot water cylinder) takes cold water directly from the mains and delivers hot water to your taps and showers at mains pressure. That means no cold water tank in the loft and no relying on gravity to push water around your home.
Fast Facts
Supply and installation cost: £900 to £3,500
Cylinder unit price: £400 to £2,000
Installation labour cost: £500 to £1,500
How much does an unvented hot water cylinder cost?
An unvented hot water cylinder, also known as a pressurised hot water cylinder, costs between £900 and £3,500 in total for supply and installation.
| Item | Unit | Cost+VAT (lower range) | Cost+VAT (higher range) |
|---|---|---|---|
| Unvented hot water cylinder (supply only) | Per unit | £400 | £2,000 |
| Unvented hot water cylinder installation (labour only) | Per project | £500 | £1,500 |
| Replacing hot water cylinder (labour only) | Per project | £300 | £500 |
| Last updated: July 2026 Our costs are ballpark averages - get a local tradesperson to quote now | |||
Unvented hot water cylinder prices
The first cost you'll need to factor in is the price of your unvented hot water cylinder itself.
Pressurised hot water cylinder costs typically fall between around £400 and £2,000.
However, this can vary widely depending on lots of factors, including the cylinder's size, make and model.
In particular, which type of unvented hot water cylinder you opt for will play a big part in establishing your overall costs.
There are two main types:
Direct unvented hot water cylinders
Indirect unvented hot water cylinders
The difference lies in how they heat water. While a direct cylinder heats water using electricity via an immersion heater, an indirect cylinder uses gas from a boiler.
Generally speaking, direct cylinders cost less than indirect ones, so you can expect direct hot water cylinders to fall at the lower end of the price scale.
Unvented hot water cylinder installation cost
Next, you'll need to factor in the cost of installation.
The average hot water cylinder installation cost ranges from around £500 to £1,500.
However, this can vary depending on the complexity of the installation and the amount of work required.
It's important that you have your hot water cylinder installed by a professional who knows what they're doing, for both safety and to ensure that you validate your warranty.
While many different tradespeople may have the skills to install your unvented hot water cylinder, from plumbers to heating engineers and even some builders, you'll need to make sure your installer has an Unvented G3 certificate.
This certifies that your installer has the skills and training needed to fit this type of hot water system. It also means they can self-certify that their work meets Building Regulations.
You cannot legally self-certify this work without a G3 qualification. Most homeowners don't hold one, so this isn't a DIY job.
A straightforward like-for-like swap typically takes one day. A full system changeover (for example, converting from a combi boiler to a system boiler and unvented cylinder) can take two days or more, depending on the pipework involved.
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Cost of replacing an unvented hot water cylinder
Hoping to replace an existing unvented hot water cylinder, rather than installing a new one from scratch? This can lower your installation costs significantly.
As a rough guide, you can expect to pay between £300 and £500 in labour costs (not including the price of the new cylinder itself).
Replacing a direct unvented hot water cylinder in an existing system and the same location will typically cost the least.
This is because direct cylinders are generally the quickest to install. We're talking around a day at most.
Meanwhile, replacing a direct cylinder with an indirect one will typically fall at the higher end of the price scale, as this will require new pipework and fittings.
Unvented hot water cylinder service cost
A service typically costs between £80 and £150 and should be carried out by a G3-qualified engineer once a year.
Annual servicing keeps the cylinder working safely and maintains the manufacturer warranty.
During a service, the engineer checks and replaces the pressure relief valve, expansion vessel and thermostat as needed.
You may also want to check the cost of fitting a thermostat on a hot water cylinder if this needs replacing separately.
What factors affect the cost of an unvented hot water cylinder?
Several factors can push your unvented hot water cylinder cost up or down, from the size of the unit to where you live. Here are the main ones.
Cylinder size
Some hot water cylinders can store more water than others.
As you might expect, bigger cylinders that have a higher capacity will typically cost more, as will those with additional features.
Cylinder type
As we've touched upon already, you can choose between direct or indirect unvented hot water cylinders.
Direct cylinders not only cost less to buy, but they're also quicker to install and therefore tend to come with lower installation costs.
Make and model
Not all unvented hot water cylinders are made equal.
A cylinder made by a manufacturer renowned for reliability, and with long product guarantees, will understandably cost more than a 'cheap and cheerful' one. But it's also likely to save you money in the long run!
Complexity of the job
Some jobs are more complex and time-consuming than others.
For instance, replacing a combi boiler with an indirect hot water cylinder and system boiler will cost more than replacing a direct hot water cylinder like-for-like.
Switching from a combi boiler to a system boiler and unvented cylinder is one of the most complex and expensive scenarios. On the other hand, replacing a like-for-like direct cylinder is at the simpler end.
Similarly, if you want to move your hot water cylinder at the same time as replacing it, this will incur additional costs.
You can get a sense of the broader project cost by looking at central heating installation cost guides.
Your location
The cost of labour can range widely across the UK.
As a general rule, costs tend to skew higher in big cities like London. But you may also find you face higher call-out charges for remote areas such as the Scottish Highlands.
It's smart to get at least three quotes from installers near you, so you can be sure you're getting a fair and competitive price for the work. It's also worth checking our plumber cost guide to understand typical day rates before you request quotes.
Cylinder lifespan and age
An unvented hot water cylinder typically lasts between 20 and 25 years, though this depends on the quality of the unit, how well it's maintained, and local water hardness.
If your cylinder is approaching the end of its lifespan, or if you're noticing reduced water pressure, slow recovery times, or signs of corrosion, it may be more cost-effective to replace rather than repair.
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Unvented hot water cylinder cost: job estimator tool
Get an approximate quote for your unvented hot water cylinder installation with the Checkatrade job estimate calculator.
Type out a few details about the cylinder you want, and the tool will use our data to give you a rough quote - so you know what to expect.
Job Estimate Calculator
Are unvented hot water cylinders worth it?
Unvented hot water cylinders can be well worth the cost for the right homeowner.
Here are just a few of their benefits.
Improved water pressure
With an unvented hot water cylinder, water is fed off the mains supply.
This means that the pressure sent to taps and showers in your home should be stronger than with a gravity-fed vented hot water cylinder.
Great for busy households
Unvented hot water cylinders are great for large and busy households.
They allow occupants to run several hot water taps at once, meaning no more queues to use the shower!
Space saving
An unvented hot water cylinder allows you to do away with your cold water tank, which will help you to save space in the home.
Plus, you can put the cylinder pretty much anywhere you want. It won't need to be in a loft as you're not relying on gravity to move water around your home.
If you do need to remove an old cold water tank as part of the job, it's worth factoring in the cost of removing a water tank separately.
No frozen pipes
As your unvented hot water cylinder doesn't need to be located in the loft, this removes the risk of frozen loft pipes.
Plus, it does away with the risk of flooding if those frozen pipes then burst!
Doesn't require a gas supply
You don't need to have a gas supply to get a direct unvented hot water cylinder.
This is because direct cylinders heat the water using an immersion heater, powered by electricity.
Completely sealed
Last but not least, an unvented hot water cylinder system is completely sealed.
Your water won't be sitting around in a tank for days on end as it comes straight from the water supply. So, it can't get contaminated.
Unvented vs vented hot water cylinder: which is right for you?
If you want mains-pressure hot water and no cold water tank in the loft, an unvented cylinder is the right choice. If budget is your main concern and you're happy with lower pressure, a vented cylinder costs less to buy and fit.
A vented (gravity-fed) cylinder is cheaper to buy and simpler to install, and it doesn't require a G3-qualified installer. However, it needs a cold water storage tank in the loft and delivers lower water pressure than an unvented system.
An unvented cylinder has a higher upfront cost and must be installed by a G3-certified engineer. In return, you get mains-pressure hot water, no cold water tank and the flexibility to put the cylinder almost anywhere in the home.
If you have a direct cylinder, you heat water with electricity. See our immersion heater cost guide to understand the running costs involved.
If you want an indirect cylinder and don't already have a compatible boiler, you'll also need to factor in new boiler costs for a system boiler to drive it.
For a completely different approach without any storage tank, you could also compare the cost of a tankless water heater.
Key takeaways
An unvented hot water cylinder can improve your water pressure and save space at home
Average unvented hot water cylinder prices range from £400 to £2,000
Unvented hot water cylinder installation costs average between £500 and £1,500
Annual servicing typically costs between £80 and £150 and should be done by a G3-qualified engineer
A well-maintained cylinder should last between 20 and 25 years
Costs vary based on factors like the type of unvented hot water cylinder, the amount of work required and your location
Always get at least three quotes to get a feeling for a range of local companies and ensure you're getting a competitive price for the work
Unvented hot water cylinder cost checklist
Use our handy checklist to make sure you've ticked everything off when planning your unvented hot water cylinder installation. That way, you're a step closer to getting the most accurate quotes, and the smoothest install.
Your unvented hot water cylinder cost checklist
Before getting quotes, here's what to check:
Finding a qualified unvented cylinder installer near you
Finding a qualified installer for an unvented hot water cylinder is easy with Checkatrade. We check and verify all of our members, to make sure everyone meets our quality standards.
Just enter your postcode, and we'll show you the unvented hot water cylinder installers who operate in your area.
Find a plumber near you
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 the size and type of your current cylinder (direct or indirect, and its litre capacity)
Describe where it's located and whether you want it moved
Explain whether you're replacing like-for-like or changing system type (e.g. combi to system boiler)
Mention any access restrictions, such as a tight airing cupboard or difficult pipework runs
Say whether the existing cylinder is still working or has failed completely
Or download the Checkatrade app to get started!
FAQs about unvented hot water cylinder costs
A straightforward like-for-like replacement typically takes one day. Converting from a combi boiler system or moving the cylinder to a new location will take longer, often two days or more. Your installer will be able to give you a more accurate timeframe once they've assessed the job.
No, not unless you hold a G3 qualification. Unvented hot water cylinders operate at mains pressure and must be installed by a certified engineer under Building Regulations. Anyone without a G3 certificate cannot legally self-certify this work.
With regular annual servicing, an unvented cylinder should last 20 to 25 years. Poor maintenance or hard water can shorten its lifespan, however.
Annual servicing typically costs between £80 and £150, depending on your location and the engineer. A service checks safety components, including the pressure relief valve and expansion vessel, to check they're still operating safely.
A direct cylinder heats water using an electric immersion heater. An indirect cylinder uses heat from a boiler.
Direct cylinders are generally cheaper to buy and install, but indirect cylinders can be more cost-effective to run if you already have a gas boiler.
No, planning permission is not needed for an unvented hot water cylinder. However, the work must comply with Building Regulations (Part G), which your G3-certified installer will self-certify on completion.
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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