Worcester 24i Boiler (System) Review [2023 Edition]

Thinking about buying a new boiler and struggling to decide which one’s going to offer the best value for money?

This 5-minute review covers everything you need to know about the high-performing Worcester 24i system boiler, including features, sizing, prices, and the cheapest way to get this boiler installed.

The Greenstar i System Range

If you’re looking at the Worcester Bosch 24i, you’re looking at the most powerful in the Greenstar i range. 

The range includes the 9i, 12i, 15i, 18i, 21i, and of course the 24i. The different sizes are suitable for different sized properties. For larger properties, there’s a 27i compact, which will fit into a standard sized kitchen cupboard.

It’s worth noting that system boilers are slightly different to combis in terms of sizing. That’s because a combi needs the power to provide ALL your hot water and heating on demand. A system boiler stores hot water in a cylinder, so it doesn’t need the output of a combi boiler to achieve the same results.

Worcester Greenstar 24i Features Worth Mentioning

Condensatesure Siphon

The Greenstar 24i comes with the Condensesure Siphon, a built-in feature that can stop the condensate pipe from freezing over.

Towards the start of 2021, we had a few days of ridiculously cold weather, well below zero. This website went from seeing 1,000-2,500 visits a day to over 19,000 in the space of 15 hours. Needless to say, it nearly crashed.

Most people coming to the site were suffering from their condensate pipe freezing. When this happens, harmful condensed gases aren’t expelled from the boiler, so it locks out (stops working). It’s easy to fix, but incredibly annoying. And if you don’t know how to fix it, you’re going to be paying for an emergency call out.

With the Condensesure Siphon, your 24i boiler will be protected down to -15°C for up to 48 hours. This means your boiler can continue running during the coldest day of the year, without undergoing undue strain.

To make the most out of this feature, you’ll need 32mm pipework over the standard 22mm, not exceeding 3m.

Low-energy Pump

As its name suggests, Worcester’s low-energy pump is designed explicitly to consume less energy. These pumps run on electricity and operate as long as the heating system continues to circulate hot water through your radiators. Thanks to this pump’s energy efficiency, the Worcester Bosch 24i will consume less electricity while in operation.

Compatibility with Greenskies Solar Panels

The Greenstar 24i is compatible with Greenskies photovoltaic panels, which means the panels can be used to supplement the boiler’s hot water output. In a typical UK winter — believe it or not — photovoltaic panels can produce anywhere between 20-30% of an average home’s hot water needs. That’s 20-30% less strain on your gas-fired boiler!

Note that these types of panels work best in a setup that includes a hot water cylinder, which is why the Greenstar 24i is a perfect candidate with which to pair these panels.

Is The Worcester Bosch 24i The Right Size Boiler For You?

The Greenstar 24i is suitable for you if:

1. You have a hot water storage tank and want to swap and old system boiler for a new one
2. Have up to 10 radiators in an average 3-4 bedroomed home.

The 24i is suitable for averaged sized homes, with average hot water and heating output.

If you want to run multiple taps and showers at once, have more than 10 radiators, or a large home with a conservatory or extension, you’ll need a bigger boiler.

Typical examples would include the Greenstar 30CDi Classic System, and the Greenstar 35CDi Classic System.

Greenstar 24i Boiler Dimensions

The Worcester Greenstar System has a downfall — it’s physical size.

The Greenstar 24i for instance, is 710 x 400 x 330. It’s not a huge boiler by any means, but it’s just big enough that it won’t fit into your average kitchen cupboard.

Space is at a premium and having a wall-hung boiler isn’t exactly ideal. Where possible, most homeowners want their ugly boiler fitted well out of the way.

Now, we’re not saying that the 24i isn’t a handsome appliance — it really is. But it’ll take up more room than a comparable compact system or combi boiler, like the Worcester 27i or 30i models.

Worcester 24i Boiler Prices (Including Installation)

Expect to pay around £1,050 for a Greenstar 24i. Typically, unless there’s a special discount or package deal, that’s not going to include a flue, extensions, or elbows.

How Much Does a Worcester Greenstar 24i Cost To Install?

Of all the options, there are two out there that offer the best value for money when it comes to getting your new boiler installed.

1. Heatable

The first option is Heatable. A new kid on the block for online boiler installs, Heatable is a company that puts technology above salespeople to reduce costs. Naturally, Heatable are supplying Viessmann and Worcester boilers at ridiculously low prices.

Whilst installers across the country can compete with big national companies easily when it comes to most brands, Heatable are slowly becoming the go-to place to get a Worcester boiler fitted.

As an example, most installers are going to quote around £2,650-£2,800 for a 24i installation. National installers are likely to be WELL in excess of £3,000.

If you check for yourself, you’ll likely see that Heatable’s offer on the Worcester Greenstar 24i is lower, AND it includes a free boiler filter and system clean, along with boiler controls and a tidy, 10-year warranty.

There’s another good option to consider — the Worcester 27i compact. This one handily fits into your kitchen cupboard AND gives you 3kW more in heat output. The price? Roughly £20 more than that of the 24i.

Go and see for yourself. There’s a multiple-choice questionnaire that takes around 90 seconds, and you don’t even need to put in a phone number or email to get a quote.

If anything, it’s a great way to compare when it comes to getting quotes from our second favourite option:

2. Local Installers

If you want to get good prices on a Worcester 24i system installation, you need to get a few different quotes. Whilst local installers might not have the clout that Heatable has when it comes from purchasing from Worcester, they may be cheaper on labour.

So, I’d always go ahead and get some quotes from local installers for a Worcester installation, too. Nothing ventured, nothing gained… and all that nonsense 😊.

But remember, you’ll want a Worcester Bosch accredited engineer — non-accredited engineers won’t be able to get you the maximum warranty on offer.

Another thing worth noting here, is that no property is the same. There might not be a Worcester boiler that’s perfect for your property. And, as local installers aren’t tied to Worcester, they’ll be able to suggest alternatives.

Is the Worcester Bosch Warranty Any Good?

Warranty is incredibly important when it comes to boilers. There are various manufacturers pumping out cheap boilers, with little more than 2-year warranty. Avoid them like the plague.

As you probably know, a boiler manufacturer wants to cover your repair bills (thanks to the warranty) just as much as you do. So, think of it this way — the warranty being offered is a good indication of product quality.

A cheap boiler versus a quality one, like a Worcester Bosch, might only save you £200 or so upfront on a £2,400 installation. That’s because a great chunk of boiler installation costs is made up of other parts and labour, not just the boiler. But there’s a good chance you’ll end up spending much more than the £200 you saved on boiler repair costs when it’s out of warranty.

That’s why we like the Greenstar i System range — you’ll be able to grab the 10-years warranty when you buy through Heatable.

Worcester 24i Boiler Review: Verdict

The Worcester 24i is a great all-rounder, and easily one of the best Worcester system boilers.

The 24i powerful, has a high efficiency rating, comes with a range of handy features, and boasts a long, 10-year warranty.

The latter is essential — not only does such a long warranty show Worcester’s confidence in their product, but it also means that you’re not on the hook for repairs or replacement within a decade of your purchase.

The only downside is that this boiler isn’t quite small enough to fit into a cupboard. But if you can live with that, then go ahead and get your fixed quote on the Worcester 24i by filling in this quick, anonymous survey from Heatable.

What’s Next?

Thanks for reading our quick review and write up of the Worcester Greenstar 24i System.

Still confused about which boiler to install and the associated costs? We’ve curated a detailed guide to buying a new boiler here.

Or, you can always ask a question by submitting a comment below and we’ll answer as soon as we can.