Ideal Vs. Glow-worm – Which is Best? Re September 14, 2021

Ideal Vs. Glow-worm – Which is Best?


Throughout this blog, we will be comparing the iconic, Ideal boilers against the boiler brand, Glow-worm

Purchasing a new or replacement boiler is one of the most important buying decisions a homeowner can make. Your boiler should last you between 10-15 years, so making sure you choose the correct boiler for your home is vital. 

WarmZilla also offers boiler finance for those looking to spread the costs for a more premium boiler.

For us to show a fair comparison, we will be comparing a combi boiler, system boiler and a regular boiler from both boiler brands to help identify which boiler brand is the most suitable for your home. 

Both companies have a great reputation and both manufacture excellent boilers, but which is the best boiler? It’s going to be a close call, but there can be only one winner.

Side note, if you’re looking for a new boiler but you can’t decide which boiler you want, why not use our Boiler Comparison Tool which allows you to compare up to three boiler models or brands at once, to help you find the perfect boiler for your home.

The boiler models we will be comparing are the following:

Before we go into detail about the boilers discussed, here’s some information about the history behind the brands.

Ideal History

In the world of boilers, Ideal Heating is known to be a more cost-friendly boiler brand in comparison to other boiler brands such as Worcester Bosch and Vaillant, nevertheless, their boilers are still reliable and efficient, which is why we recommend them here at WarmZilla. 

Founded in 1906, Ideal Heating has been providing the best quality boilers to its customers for over 100 years. Ideal claim that they remain at the forefront of the domestic and commercial heating market, 

“Leading the industry in setting new standards and challenging technological boundaries”

Ideal Heating’s mission is to be dedicated to providing a reliable, competitively priced product range as well as delivering incredible customer service. 

For more information about the history of Ideal Heating, follow the link.

Glow-worm History

Glow-worm has several different gas boiler ranges that encompass all different types and sizes of boilers including combi boilers, system boilers, and regular heat-only boilers.

Originally producing boilers back in 1934 at the Derwent Foundry in Derbyshire, Glow-worm, for the past 80 years state that they have been focused on offering their customers, reliable and highly efficient products.

They also claim that “it has been the drive which has led us right to the top as one of the leading heating manufacturers in the UK”. 

In 2001 Glow-worm became a part of the Vaillant Group, Europe’s second-largest heating company. Vaillant employs over 12,000 people across Europe and China, providing innovative heating, ventilation, and air-conditioning technologies to hundreds and thousands of homes all over the world. 

If you’d like to find out more about Glow-worm, please feel free to explore their heritage.

Now that we’ve learned a little bit about the history of each brand, let’s have a look at what their customers think of the brand.

During the Which? Best Boiler Survey in 2020, more than 7,000 members of the public were asked to rate both Ideal Heating and Glow-worm as a brand. Ideal was awarded an overall brand score of 69%, coming in at 6th place out of the 13 brands that were rated. Glow-worm scored an overall brand score of 57% and ranked 7th place out of 13 boiler brands, not far behind Ideal boilers. 

Customers of both Ideal and Glow-worm boilers were asked how they felt about their boiler and whether or not they would recommend them to a friend or family. In addition to this, 150 Which? Trusted Traders (boiler engineers) were asked their views on the boiler brand.

The 2020 Which? Best Buy annual survey results show that Ideal is found to be more reliable and efficient than Glow-worm boilers. Ideal boilers are known to be cost-efficient yet robust boilers. Ideal is also known to offer great customer aftercare, including up to a 10-year warranty on selected boiler models. Although Glow-worm boilers are found to be less reliable than other boiler brands, they are still loved by customers. A star rating of 4 out of 5 also for customer score supports this.

Touching on brand aftercare, here at WarmZilla, we feel that aftercare is just as important as purchasing a boiler and should not be brushed over. If you’re interested to know which brand we feel has the best aftercare, we have a separate blog that discusses this. 

Looking at Trustpilot, Ideal Heating has over 10k reviews with 4.8 stars out of 5 and 95% of their reviews are above average. This supports the customer reviews in the Which? Best Boiler Brand Survey Results, showing that Ideal’s customers are more than happy with their boiler, its performance, and its reliability. 

Here are a few of Ideal’s Trustpilot reviews that also show that Ideal’s customers are more than happy with their services: 

“Had the same engineer call today and as in the previous visit, he was very polite, professional and tidy with his work. As for the company, phoned yesterday reporting we had no hot water and 24 hours later problem solved can’t ask for better than that.”

Glow-worm has 4.7 stars out of 5 and over 5k reviews on Trustpilot.  A whopping 96% of their reviews are above average, which also supports that although they may not have a sought-after boiler brand, their existing customers are happy with their boilers and their performance. 

Here are only a few of the Trustpilot reviews for Glow-worm: 

“Excellent service. Extremely well installed and unfailing in delivering warmth and comfort during the winter. Impressive.”

“Our new boiler is excellent, very efficient and quiet, the fitter who we have used for many years, made a prompt replacement to our old boiler and was very quick and clean.”

Now let’s get into the bit we’re all here for, comparing the boiler models. 

Combi Boiler Comparisons


Boiler MakeIdeal Glow-worm
Boiler ModelLogic Max Easicom3
Boiler TypeCombiCombi
Fuel TypeGasGas
CH kW Output 24kW24kW
DHW kW Output24kW24kW
Efficiency Rating94%94%
Band RatingA-RatedA-Rated
Standard Warranty10 years3 years
Flow Rate9.9 l/min10 l/min
ErP RatingA Heat | A WaterA Heat | A Water
Dimensions (HxWxD)700mm x 395mm x 278mm700mm x 418mm x 300mm
Price (boiler only)*£860 £624

The first two boiler models we will be comparing are the Ideal Logic Max 24kW combi boiler and the Glow-worm 24kW Easicom3 combi gas boiler. 

Both combi boilers seem to be similar in their performance, both offering an output of 24kW, which is perfect for small to medium-sized homes with up to 15 radiators and a single bathroom. 

Both the Ideal Logic Max combi and the Glow-worm Easicom3 combi have an efficiency rating of 94%, meaning that only 6% of the gases that are used if you have either of these combi boilers installed are wasted. In financial terms, that’s 6p for every £1 you spend on your energy. 

Both combi boilers are similar in dimension and flow rate. What is a flow rate you ask?

The hot water flow rate expressed as litres per minute (LPM), indicates the speed at which the boiler can heat water supplied to the hot water outlets (taps, showers etc). Hot water flow rates on combi boilers can vary from 9.8LPM to 25LPM.

On the other hand, the most noticeable difference between both the Ideal Logic Max combi boiler and the Glow-worm Easicom3 combi boiler is their warranty lengths. 

The Glow-worm Easicom3 only has a standard manufacturer’s warranty of 3 years, whereas, the Ideal Logic Max combi boiler has an amazing 10-year warranty!

It is important to note that warranties have to be registered within 30 days of installation for the full warranty length to be honoured. 

Before we make our final decision on the winner of the battle of the combi boilers, let’s take a look at what each boiler model has to offer.

Ideal Logic Max Combi Boiler:

  • Large digital display screen
  • Easy to reach pressure gauge
  • Easy to use controls 
  • Built-in frost protection for extra peace of mind
  • Hardwearing and scratch-resistant casing 
  • Low-lift weight for easy installation
  • Compatible wireless controls 

Glow-worm Easicom3 Combi Boiler:

  • Easy to use controls 
  • Built-in analogue timer
  • Frost protection for extra peace of mind
  • Easy to read display screen

The final factor to compare is the price. Now, right off the bat, you’re probably thinking, “I’m going with the cheaper option”. However, it’s important to remember that cheaper is not always the best option. When we look at the warranty that you get with the Ideal Logic Max 24kW, you have an extra 7-year where the worry of paying out to fix your boiler is not on your shoulders. The cost of a repair on a boiler can be very expensive, so the price of a couple of hundred pounds, in the long run, is worth paying. 

This round’s winner is inevitable and has to be awarded to Ideal.

System Boiler Comparisons


Boiler MakeIdeal Glow-worm
Boiler ModelLogic PlusEnergy 
Boiler TypeSystemSystem
Fuel TypeGasGas
CH kW Output 24kW25kW
DHW kW Output24kW25kW
Efficiency Rating94%89.3%
Band RatingA-RatedB-Rated
Standard Warranty7 years7 years
Flow RateN/AN/A
ErP RatingA HeatA Heat
Dimensions (HxWxD)700mm x 395mm x 278mm700mm x 390mm x 280mm
Price (boiler only)*£850£810

The system boilers that we will be comparing are the Ideal Logic Plus 24kW system boiler and the Glow-worm Energy 25kW system boiler. 

At first glance, the major difference that we notice between both system boilers is the efficiency ratings. The Ideal Logic Plus 24kW has an efficiency of 94%, whereas the Glow-worm Energy System 25kW has an efficiency of only 89.3%, making it a B-Rated system boiler. 

In financial terms, this means that for every £1 you spend on your energy bills, 10p of it is being wasted.

Both boilers are very similar in what they offer when it comes to size and kW output, with both system boilers being suitable for small to medium-sized homes with moderate demand for central heating. 

Both system boilers also appear to have the same warranty lengths of 7-years. However, when you purchase a new or replacement Ideal system boiler with WarmZilla, you will receive an 8-year warranty.

You may have read in our boiler types explained blog, that when purchasing a new or replacement system boiler, you need to have the additional space in your home for the extra hot water cylinder. This is typically installed in an airing cupboard or similar-sized space in your home. 

Let’s take a look at both boiler’s features.

Ideal Logic Plus System boiler:

  • Built-in frost protection for peace of mind during the colder months
  • A large LCD screen for easy use
  • User-friendly controls 
  • A low-lift weight for easy installation
  • Scratch-resistant casing 
  • Compact and modern design 
  • LPG conversions for off-grid properties 
  • Wireless controls
  • Good Housekeeping Award in 2013 and 2017
  • Queen’s Award in 2013
  • Quiet Mark approved 
  • Made in the UK

Glow-worm Energy System boiler:

  • Easy to use controls
  • Flexible flying options
  • LCD screen 
  • Built-in frost protection
  • Quiet Mark approved

Finally, let’s take a look at the prices.

There is a £40 difference between both boilers. The Ideal Logic Plus system boiler wins hands down when it comes to cost, as you are getting a more efficient boiler, with an extra year warranty for only £40 extra. 

After looking at the system boiler comparison table alongside the features of both system boilers, based on Ideal’s higher efficiency rating, longer warranty, awards, and an extensive list of great features, the Ideal Logic Plus system boiler has secured first place in the battle of the system boilers. 

Now on to the regular boilers.

Regular Boiler Comparisons


Boiler MakeIdeal Glow-worm
Boiler ModelLogic Ultimate3
Boiler TypeRegularRegular
Fuel TypeGasGas
CH kW Output 24kW25kW
DHW kW Output24kW25kW
Efficiency Rating93%86.9%
Band RatingA-RatedB-Rated
Standard Warranty2 years5 years
Flow RateN/AN/A
ErP RatingA Heat A Heat 
Dimensions (HxWxD)700mm x 395mm x 278mm600mm x 375mm x 280mm
Price (boiler only)*£898£830

The regular boilers we will be comparing are the Ideal Logic 24kW regular boiler and the Glow-worm Ultimate3 25kW regular boiler. 

Unlike the combi boilers and system boilers we have compared, there are some noticeable differences between these two regular boilers. 

The first thing we notice is the efficiency rating. Similar to the Glow-worm Energy system boiler, the Glow-worm Ultimate3 regular boiler has an efficiency rating of 86.9%, making it a B-Rated regular boiler.

If you were to have the Glow-worm Ultimate3 regular boiler installed, you would be losing over 13% of the fuel you are using when your central heating is turned on. If you currently have this regular boiler installed, we recommend upgrading it to a newer, more efficient regular boiler, to help you save money on your energy bills. 

Another difference is warranty length. Now, you may be thinking that Glow-worm has the upper hand when it comes to warranty, with a standard manufacturer’s warranty of 5 years, whereas the Ideal Logic regular boiler only comes with a standard 2-year warranty. However, this is a great time to remind you that when you purchase a new or replacement Ideal boiler with WarmZilla, you will receive an 8-year warranty. 

Both boilers are similar in size and kW output, both suitable for smaller homes with up to 15 radiators and a single bathroom. 

Side note, if you choose to purchase a regular boiler, your boiler will need to be installed alongside an additional hot water cylinder, a cold water tank, and a feed. For this reason, regular boilers are not recommended for properties with limited space such as flats etc.

Let’s take a look at both regular boiler’s features.

Ideal Logic Regular boiler:

  • Built-in frost protection for extra peace of mind during the colder months
  • A backlit LCD screen for easy use and reading
  • User-friendly controls 
  • An easy to see pressure gauge 
  • Flexible flue installation 
  • 10-years warranty on the heat exchanger
  • Compact fit for easy installation 
  • Quiet Mark 
  • Wireless controls 

Glow-worm Ultimate3 Regular boiler: 

  • Compact and lightweight design
  • Easy to use interface
  • Wireless controls
  • Built-in frost protection for peace of mind
  • Aluminium heat exchanger

And now to compare prices. Similar to the system boilers, for the sake of an extra £68 for the Ideal Logic regular boiler, you will be getting a more efficient boiler, which saves you money on your energy bills in the long run, as well as an extra 3 years warranty when you purchase with WarmZilla. It’s a no-brainer. 

So, after taking into consideration both regular boiler’s performance, efficiency ratings, price, warranty lengths, and features, we have come to a final verdict on our winner of this round and our WINNER between Ideal and Glow-worm. 

And our winner is… IDEAL.

*Boiler prices have been taken from an online source at the time of publication. Please note these prices are for the boiler online and prices may vary depending on your supplier. The price of installation will have an effect on the over price of your boiler.

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