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Best Heat Only Boiler Models, Prices, and More [2023 Buyer’s Guide]

Heat-only boilers may seem outdated (and very confusing), but they’re still a suitable solution for many homes. If you’re looking for a new heat only boiler, you’re in the right place.

In this guide, we’ll explain what heat only boilers are, talk about purchase prices, the cost of installation, and offer recommendations for the best brands producing heat only boiler ranges.

Heat only boilers

NEED A NEW BOILER? If your heat-only boiler breaks often and you’re considering a replacement, you can get a fixed-price quote by filling in this 90-second questionnaire from Heatable.

What Is a Heat Only Boiler?

A heat only boiler goes by several names, including “traditional boiler,” “regular boiler,” and  “conventional boiler”. 

If your property uses a heat only boiler, the domestic hot water and central heating system will be connected to a hot water cylinder.

Regular Boiler in a Vented System

In a vented system, you’ll also have a feed and expansion tank and a cold-water storage tank in the loft space. These water tanks help maintain the correct water pressure in the radiators and supply the taps with water.

Regular Boiler in an Unvented System

On the other hand, in unvented heating systems, you’ll have an expansion vessel and a hot water tank, but no feeder tank for domestic hot water.

Which Heat Only Boiler Should You Buy?

There’s plenty of false economy in the heating industry. So, it’s worth being wary of cheap brands, particularly when they offer a short warranty. Since the boiler itself only makes up 35% of the installation cost, saving 10-20% on a cheaper model makes little difference to the what you’ll pay overall.

We usually advise investing in the best boiler possible. Doing so will reduce long-term repair costs, and get you an appliance that’s more efficient than a cheaper equivalent.

The Best Heat Only Boilers

There’s little point suggesting an actual boiler model, like the Ideal Logic+ 18kW, for instance. That’s because, even with a rough idea about your property size, it’s hard to determine the exact kW boiler you need.

However, what I can do is offer up some recommendations, based on the best sellers at my time working for an independent plumbing merchant.

Worcester Greenstar Ri Regular Boiler

If you’re in the market for a Worcester heat only boiler, you’ll want to head for their Greenstar RI range.

Now, note that a Worcester Bosch warranty is sometimes tough to nail down. For a start, it constantly changes alongside their promotions.

So, you can expect to get a 5-year warranty as standard with the Greenstar RI. That said, do speak to a Worcester Accredited heating engineer to determine if there’s a better warranty on offer. Sometimes, warranties can be extended by using a Worcester Accredited engineer and fitting Worcester-branded parts (such as heating controls and boiler filters).

As an example, Heatable can offer a warranty up to 10 years, and their boiler installation costs are extremely competitive. Use Heatable’s clickable form to find out what deals are currently on offer.

Ideal Logic+ Heat Only Boiler

Ideal Boilers are a British manufacturer producing top quality boilers at low prices. Compared to the Vaillant and Worcester Bosch picks on this list, this Ideal heat only boiler is DIRT-cheap.

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Worcester boilers from as little as £1,965.

With the Logic range, it’s crucial that you choose the Plus model. The features and efficiency are similar to the standard Logic, but the warranty is where the big difference lies. The Logic Heat gets you only 2 years of coverage, whereas the Logic Heat Plus comes with 7 years, and the price difference is trivial – it’s worth it.

That said, both the Logic and Logic Plus offer a 10-year warranty on the heat exchanger — one of the most expensive boiler parts.

Vaillant EcoTec Regular Boiler

The EcoTec range is better known for combi models, but you’ll find Vaillant heat only boilers in this range, too. If your fitter is suggesting a Vaillant EcoTec, we’d be inclined to listen to them.

With the EcoTec, you’ll pay a little more than you would compared to an Ideal heat only boiler. But there’s plenty of choice with 12, 15, 18, 28, 30 and 38kW outputs from Vaillant’s 412, 415, 418, 424, 430, and 435 models.

The Vaillant heat only boiler offers you a basic 5-year warranty. This can be extended to 7-years, but the appliance HAS to be fitted by a Vaillant Accredited Engineer.

Heat Only Boiler vs  System Boiler

System boilers work much like their heat only cousins. They, too, have a hot water storage cylinder; however, a system boiler doesn’t require a cold-water feed tank. This tank is usually located in your loft, and takes up a fair bit of space.

So, if you see a cylinder but not a cold-water storage tank, you need to go and check out our guide to system boilers — that’s the type of boiler you have.

Heat Only Boiler vs Combi Boiler

Heat only boilers are typical of an old central heating system. Newer setups, on the other hand, usually utilise the less cumbersome combi boilers. The latter rely on mains supply and provide heating and hot water on demand, so they don’t need hot water cylinders or water storage tanks to operate.

But there is a place for both combi and heat only boilers. Thanks to the water storage facility, heat only boilers don’t need to heat hot water on demand like a combi boiler does. That means you have hot water “on-tap”.

The BIG downside is that heat only boilers take up lots of room. In contrast, a combi can be a huge space saver.

If you regularly use 2 or more taps/showers at once, a combi may not meet your demand for hot water.

So, if you’re in a property that needs high hot water output, you’ll want a system or heat only boiler, not a combi.

Ready to get your boiler installed? Get a fixed price on screen in 90 seconds using this anonymous, clickable form.

Worcester Bosch Greenstar 4000

Heat Only Boiler Installation Costs

You’ll see combi boiler deals from as little as £2,500 for supply and installation. But don’t expect to be pay that little for a heat only boiler. Compared to combis, conventional boilers require more materials and labour to be installed; this is why conventional boiler installations cost more

For a start, there’s the cylinder; this part alone can cost hundreds of pounds, plus the labour to fit it. The same goes for the cold-water feed tank.

Usually, the cost of heat only installations relates to the size of the boiler and cylinder you require. Typical installation costs start at around £2,500 (inc VAT).

Want to know exactly how much it will cost to install a heat only boiler on your property? You can use this boiler price calculator on Heatable and get an on-screen price within 2 minutes. And, thanks to their low overhead, Heatable offer Worcester boilers at incredibly competitive prices.

What kW Heat Only Boiler and Cylinder Do You Need?

A 24kW boiler and a 150L tank are sufficient for a 2-bedroom property; if your home is larger, prepare to spend more on a higher-capacity boiler and a larger tank.

To get a handle on how much your installation may cost, we’ve created 2 guides here:

  1. Hot Water Cylinder Sizing
  2. Boiler Sizing

Note that these guides offer a ball park only. Properties vary (even when they’re the same size) in terms of their heating and hot water demand. And, the last thing you want is a boiler that’s too weak, or too powerful (i.e. inefficient) for your home.

Any Gas Safe boiler fitter will be able to spec a boiler and cylinder that’s perfectly suited to your property. They can consider square footage, radiator BTU, number of rooms, how many taps and showers there are, and beyond.

If you want to get an accurate heat only boiler size estimate, you can also use this clickable form from Heatable.

Heatable boiler installations

What’s Next?

Thanks for reading our 10-minute review of heat only boilers.

We regularly post up reviews, guides and advice on heating, plumbing and bathrooms. Bookmark our blog and pop back soon.

Or, if you have a question, leave a comment below and we’ll get back to you as soon as possible.



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