Sometimes knowing what you want is only half the battle when you don’t know where to get it.

If you’ve recently made the decision to buy an unvented cylinder for your home, the great news is that you’re soon going to be able to enjoy fantastic water pressure and all the heating and hot water your family will ever need.

But where are you going to find one? Well, you have a couple of options, which I’m going to go over with you below.

Option 1. Buy from a specialised plumbing merchant

There are plenty of specialised plumbing merchants around, such as City Plumbing Supplies, or Plumb Nation. Looking at these will give you an idea of the cost of an unvented cylinder, but if you go down this route, you need to really do your homework.

If not, you might come away with an unvented cylinder that is too big or too small for your home. The average size for a large property – and by far the most popular – is 210 litres. However if you buy one that is too big for your home, it could potentially be very wasteful and you’ll end up with more expensive bills.

You might also think that going to a plumbing merchant will save you money. However, in the grand scheme of things, you might end up paying over the odds as you’ll still have to pay for the cylinder to be installed, as well as for any extra parts you might need (depending on whether you get your cylinder pre-plumbed or not).

Option 2. Buy directly from a certified installer

Purchasing your unvented cylinder directly from a certified engineer and installer is without a doubt the smarter option.

I recommend going this route because I know for a fact that an engineer will be able to tell you exactly what size and volume is right for your home. He/she will also be able to fit everything you need as one package, which could save you money.

The takeaway here? A bit like investing in a new boiler, there are lots of various cylinders and specifications on the market, and sometimes it’s better to call in an expert for advice rather than taking the plunge yourself and hoping it works out for the best.

TIP: If you’re curious about guarantees for your new unvented cylinder, stay tuned for my upcoming blog post ‘All You Need to Know About Unvented Cylinder Guarantees’.

How much you should pay

Regardless of which option you go for, you need to have a rough idea first of how much your unvented cylinder should cost.

Firstly, you should note that the cost of an unvented cylinder is entirely separate to the cost of your boiler, so purchasing both at the same time will be particularly costly.

An unvented cylinder can cost anything between £500 to £1500. The cost really depends on whether your cylinder is pre-plumbed – with all the pipes already joined – or ‘naked’, meaning the engineer will still have to make all the pieces up.

On average, a pre-plumbed unvented cylinder will cost £700 without factoring in installation costs.

However, supplied and fitted, the average total cost is £1100 – this is because it can take a day to install. This is the end-cost you should really be expecting to pay.

TIP: Although unvented cylinders are pricey and can be quite the investment at the outset, they’re also incredibly energy efficient, so you will notice a difference in your household bills.


If you’ve recently made the decision to purchase an unvented cylinder, you have two main options: buy from a specialised plumbing merchant, or buy directly from a certified installer.

The first option is only really advised if you know exactly what size and volume of unvented cylinder you need – and even then, you may end up paying extra for additional parts as well as the cost of getting the unit installed in your home.

The second option means that you’ll be sure to get exactly the right size and volume of cylinder your home needs, and a certified engineer will be able to listen to you and give you advice. It also means that you’ll get everything included and installed as one package, which could save you money overall.

The average cost you should expect to pay for an unvented cylinder, supplied and fitted, is £1100.