The Best 30kw Combi Boiler [And What It Costs To Install]

In todays guide we’re going to cover 30kw combi boilers. We’ll discuss brands, reviews and prices you should expect to pay, inclusive of installation.

Boiler Sizing

First up, you need to determine if you need a 30kw combi boiler. Typically, this is going to suffice for anything up to a 3 bedroom house. But you might need something bigger or get away with something smaller.

To ensure you get the exact boiler you need, jump over to this boiler size calculator. It will account for property specific details and then list the most suitable types of boilers at the top of the screen.

Brands Producing 30kw Combi Boilers

Given a 30kw combi boiler is powerful enough for anything up to a 3 bedroomed property (and sometimes larger), they’re extremely popular. So, most type boiler brands will produce them.

Honestly, a combi boiler from any leading brand is going to work. We’ve detailed some of the best boiler makes here, which include the likes of Worcester, Ideal, Vaillant, Baxi and Potterton.

There are a couple of things that are going to help you narrow down to a specific 30kw combi boiler, and we’ve mentioned those below.


You should expect to budget somewhere in the region of £2,000 for a 30kw combi boiler installation. Naturally, you want the longest warranty possible.

Typically, we’d suggest a minimum warranty of 5-years, ideally higher. There are boilers that might be £100 or so cheaper, but offered with 2-years warranty or less, and we’d completely avoid them.

The last thing you want is a big boiler breakdown that leads to a costly replacement, just 2 years down the line.

Looking for a 5-year warranty as a minimum still gives you plenty of choice from the likes of Vaillant, Ideal and Worcester. For example, Worcester 30kw combi boilers that are installed by HEATABLE come inclusive of a stupidly long 10-year warranty.

30kw Combi Boiler Prices

So, you’ve got plenty of boilers from a range of brands in the 5-10 year warranty range. Now, it’s just a matter of price. And as we suggested above, 30kw combi boiler prices tend to hover around the £2,000 mark.

As a starting point to compare boiler prices, we’d be looking at HEATABLE.

It might not be obvious by looking at their website, but HEATABLE put technology above salespeople to bring you the best value for boiler installs, which means they get some of the most premium brands, Worcester boilers for example, at stupidly low rates. And, as you’ll see by using this boiler price calculator, those savings are passed onto the end consumer; you!

The Best 30kw Combi Boiler

Our Pick: Worcester 30i

The cheapest 30kw combi boiler from Worcester is going to be the 30i. You can read our full Worcester 30i review here, and you can see just how a cheap combi boiler is on HEATABLE here.

One thing worth mentioning though, is that the 30i ISN’T a compact boiler; it’s designed to be wall hung, in a kitchen or garage, for instance.

If you’re looking to tuck your boiler away neatly in a small space such as a kitchen cupboard, you’re going to be looking at something like the 32CDi Compact, which has much smaller dimensions.


As we’ve mentioned above, you want to make warranty the focus of your search. With the Worcester 30kw combi boiler, it’s about as good as it gets, with a solid 10-years warranty on offer.

It’s worth noting with Worcester, the warranty is only given when using an accredited installer, and certain branded products. And, that’s why we suggest heading straight for HEATABLE, as they offer the 10-years as standard, due to their special relationship with Bosch.


Around £2,000 is what you should be budgeting for a standard 30kw combi boiler installation, from a cheap local installer, and for a reasonable brand. You’ll be able to fit almost any boiler you want from Baxi, Vaillant, Ideal or Worcester at the £2-2.5k mark.

And, this is probably why HEATABLE is currently so popular. Not only are they able to install Worcester combi boilers for less than this estimate, they also come with a system cleanse, magnetic filter to protect your boiler, and even a smart thermostat!

Worcester Bosch Greenstar i from Heatable

It’s a deal that’s hard to beat, especially when you consider national household names are likely to be closer to £3,000, rather than £2,000.

Winter Protection

One of the best features of Worcester boilers is the CondenseSure siphon.

During the winter months, boilers are prone to locking out, and that’s because of condensed gases freezing in the condensate pipe, causing a blockage.

The ConsenseSure siphon eliminates this problem by releasing these condensed gases in short bursts, which eliminates the risk of them freezing. It’s able to keep your boiler up and running down to -15°C for up to 48 hours.

And, not only does this mean zero downtime for your boiler, it’s also going to mean no expensive emergency call out charges too.

Suitable Controls

You’ll have a lot of flexibility when it comes to the type of controls you can use with the Worcester 30kw combi boiler. Obviously, you can go with a basic (and cheap) thermostat, or the Worcester Wave smart thermostat.

However, the HEATABLE promise is you’ll be getting the upgraded Heatable controls installed as standard, for free.

Our Verdict

When considering all the most important things such as price, warranty and winter protection, the Worcester 30i is one of the best 30kw combi boilers on the market. And you can get on-screen prices for one here.

What’s Next?

Want to read up more on getting a new boiler installed? Check out our new boiler installation costs guide here.

Still confused about which boiler is right for your property? Drop us a line via our contact form, and we’ll do our best to help you out.




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