Glow Worm Boiler Reviews and Prices 2020

glow worm boiler reviews

Glow Worm Boiler Reviews and Prices 2020 

“Glow Worm”  likes to think of itself as a pioneer of heating solutions and has been offering the UK market all things boiler-related for the last eighty years. 

The company, founded in 1934 in a quiet town in Derbyshire, is wholly focused on delivering reliable and effective products designed to stand the test of time. 

It’s important to note, however, that Glow Worm is no longer an independent company.

In 2001, Vaillant, one of Europe’s biggest boiler manufacturers, acquired the brand and has been overseeing it ever since.

Thus, you should bear in mind that when we talk about the products of the modern Glow Worm brand, we’re really referring to the activities of another, larger multinational.

Vaillant pulls the strings in this relationship, not Glow Worm.

The following is a review on Glow Worm boilers, their features, advantages, disadvantages, and whether you should get one for you home. 


Glow Worm Combi Boilers – Our Review

Viessmann 100-W 26kW Regular Open VentChoosing the right boiler for you and your family is a big decision.

You need something that will serve you long into the future and won’t break down the moment the winter arrives.

The last thing you want is an unreliable or even dangerous piece of equipment that fails to heat your radiators and periodically spews out carbon monoxide. 

If we tried to review every single one of Glow Worm’s more than two-dozen individual combi boilers, we’d be here all day.

Instead, we’re going to talk about the general benefits of Glow Worm combi systems – and the problems.

Most modern homes use so-called “combi” boilers, devices that combine the task of heating hot water and the central heating system in a single unit.

The purpose of these boilers is to save space, provide all heating functions in one piece of equipment, and reduce maintenance costs.

Glow Worm offers a range of high-efficiency combi boilers, including Ultimate 3, Energy 35, Betacom 4, Easicom 3, and its value product, Essential.

These boilers are all rated ErP A for efficiency, except for the Essential, and many of them are small enough to fit inside regular kitchen cupboards.

Glow Worm also offers free warranties on some varieties, including the Ultimate 3 and Essential, providing additional peace of mind.

Perhaps the most impressive feature of the company’s combi boilers is that some do not need LPG conversion kits – they’ll work with alternative fuel sources right out of the box.

The company also provides numerous unit sizes, designed to cater for everyone from the smallest of apartments to the largest of mansions.


The Benefits Of Glow Worm Combi Boilers

Let’s list some of the critical benefits of Glow Worm combi boilers: 

  • While not the best-known brand for consumers, it’s renowned among boiler maintenance professionals and uses similar parts to Valiance-branded products, making them easy to service
  • Maximum energy efficiency on all combi boilers except Essential
  • Comes in a variety of sizes, providing discreet options for those who want to conceal their boilers in attractive cabinets
  • Modern design and a bright display panel on the front providing homeowners and boiler engineers with important metrics

Upgrading to a Glow Worm combi boiler can yield substantial savings for homeowners. If you’re currently using a G-rated boiler, then moving to a Glow Worm Ultimate will, according to the Energy Saving Trust, cut your annual heating bill by more than £305. 

Glow Worm System Boilers

system boiler

System boilers work in a slightly different way from combi boilers.

Instead of taking water from a tank in your loft and then using stored water to heat a water tank, system boilers heat water directly from the mains.

Most system boilers use a small cylinder to warm the water before pumping it to the rest of the house. 

Glow Worm markets its system boilers to people who live in flats, maisonettes and families with limited space.

The company’s offerings are small, compact and relatively discreet.

Just as with the combi boilers, many come with free warranty and ErP A rating. 

The Ultimate 3 system boiler is the company’s most reliable option and comes with five years parts and labour guarantee.

The slightly less costly Easicom 3 has a three-year warranty (with the opportunity to extend) and achieves the maximum ErP A rating. Unlike the other models, Glow Worm makes it in the company’s Belper factory in Derbyshire.

Finally, the Energy system boiler is a unit explicitly designed to fit inside kitchen cupboards and comes in a variety of sizes, including 12, 15, 18, 25 and 30 kW versions. 

Glow Worm’s system boilers offer several advantages over the competition.

  • First, their most recent boiler models come with bright, easy-to-read displays that you can use to set timers or diagnose problems.
  • Second, it uses automotive-grade components, designed to withstand the extreme wear and tear that boilers experience throughout their lifetimes.
  • Third, it uses something called a Grundfos modulating pump, a component that helps to slash the unit’s energy use and adds to reliability.
  • The ethos of the product, therefore, is clear: to create something that will last as long as possible.
The Benefits Of Glow Worm System Boilers
  • System boilers come with a five-year warranty or a three-year version with the option to extend (depending on the model you buy)
  • Comes with a high level of flue compatibility, enabling you to adjust the type of exhaust you use depending on your situation
  • Easy to source replacement parts
  • A high-grade aluminium heat exchanger modelled on designs from the automotive industry
  • Easy-to-read LCD for both homeowners and engineers to diagnose problems

Glow Worm employs a range of sound-deadening technologies in its system boilers to cut down on annoying whirring noises that some make.

This technology makes them ideal for those who live in cramped accommodation and want something that isn’t going to disturb their sleep (or that of their neighbours).

Glow Worm Heat-Only Boilers
heat only boiler

Some households use the classic trio of water tanks, storage cylinder and boiler unit to heat their homes.

While it’s becoming less popular, it’s still an essential market for Glow Worm and one that they intend to serve. 

The company offers three brands of heat-only boilers,

‘Energy, Ultimate 3 and Easicom 3.’

The basic Energy version is compact, operates nearly silently, and comes with an ErP A rating, helping to cut down on bills. 

The Ultimate 3 regular boiler is the company’s flagship heat-only boiler. It comes with a similar, compact design as well as an impressive five-year warranty, just like the combi and system versions of the product.

Finally, the Easicom has an extendable three-year warrant for those who want it and also comes with the company’s signature ErP A rating for efficiency. 


Glow Worm states that with its boilers, homeowners don’t face energy usage penalties if they decide that they want to stick with their traditional systems.

That’s good news: ripping out old tanks and replacing them with alternative systems is notoriously expensive.

It also means that you can avoid the disruption of major building work in your home, perhaps pushing off the need to upgrade two or three decades into the future. 

The Benefits Of Glow Worm Heat-Only Boilers

So what are the benefits of Glow Worm heat only boilers? 

  • They make use of high-grade automotive materials to enhance working lifetimes
  • High levels of efficiency across the board, including value-orientated products
  • Parts and labour warranties on select products
  • Easy for engineers to inspect, service and maintain
  • Available in a range of power outputs
  • Some models are small enough to fit in a kitchen cupboard out of sight
How Reliable Are Glow Worm Boilers? 

While Glow Worm’s range might offer an impressive array of features, the most crucial factor for most buyers is good-old-fashioned reliability.

Will the boiler continue to perform, year after year, even in sub-zero temperatures

Historically, boilers were unreliable because manufacturers imported cheap parts from overseas, primarily China.

Units would work for a few years, but eventually, problems would inevitably creep in. Even Vaillant boilers got a bad reputation for sourcing components from substandard suppliers. 

Glow Worm, however, has upped its game.

The company doesn’t rely on cheap imported components like many of its competitors (and even its parent company).

Instead, manufacturers many of the fastest-wearing critical parts in-house, helping to reduce issues that its customers face. The Ultimate 3, for instance, uses a high-quality Grundfos pump that the company makes itself. 

Are Glow Worm Boilers Costly To Install?
new boiler gas safe

As experienced homeowners know, the cost of the boiler isn’t just the unit itself, but all of the labour and accessories required to fit it.

Glow Worm does as much as it can to get the cost of installation down.

It supplies its boilers with a list of standard parts and flue accessories, helping installers fit in a variety of situations, whether bare, in a cupboard or a regular utility space.

It’s always best, though, to get a range of quotes from a variety of different installers to see who is willing to install your boiler at the lowest cost.

Do Glow Worm Boilers Have In-Built Frost Protection

It’s not uncommon for heating systems to experience frost damage.

During cold winter weather, temperatures in the pipes can get down below zero, causing the water inside to freeze and expand.

This expansion process then damages them and boiler internals, causing systemwide failure and often necessitating wholesale replacement. 

Fortunately, Glow Worm supplies its boilers with frost protection technology that stops ice from damaging the condensate pipe.

The idea behind the technology is simple: keep the condensate pipe above freezing point by letting the boiler tick over on low heat. 

Frost prevention is more important than you might initially think.

Suppose, for instance, that you’ve booked Christmas week off spend time at your relatives. While you’re away, you don’t need the heating on so your house will get cold. If temperatures drop below zero, however, it is chilly enough to freeze water in pipes, causing the damage described above.

Frost protection automatically prevents this from happening in your absence. The boiler keeps heating water gently to eliminate any chance of ice while, at the same time, maintaining low energy consumption to prevent your bills from spiralling out of control.


How Does Glow Worm Compare To Other Manufacturers?

Glow Worm’s main competition is from Worcester and Ideal Logic Plus. Both companies offer boilers in a similar price range, providing consumers with ample competition. 

In terms of the warranty, the competition is roughly the same. Ideal Logic offers a five-year warranty on its premium boilers, just like Glow Worm. 

Glow Worm’s boilers are the product of a long, evolutionary process you can trace back decades. The company believes that it has found the best solution to your boiler problems that current technology allows, using new state of the art materials as they arrive.

The firm, however, isn’t the most innovative on the market.

Its boilers aren’t game-changers – they’re essentially units that are now reaching the performance limits of the current paradigm.

With that said, the entire industry is in the same rut. Nobody has come up with a better or more affordable way, as yet, of providing water heating services in homes. 

When it comes to the volume of water that Glow Worm units can process, it’s a clear leader.

The Glow Worm Ultimate 3 is capable of hot water heating of 30.6 kW which is similar to comparable products on the market, like the Worcester 30I.

However, it takes the lead in heating output, offering an impressive 30 kW, compared to the competition’s 24 kW. 


The Verdict
glow worm boiler

Most Glow Worm boilers reviews end similarly. The conclusion is usually that Glow Worm a company with a long heritage and ample expertise in helping homeowners get the cost of their heating and hot water down.

The value proposition is undoubtedly compelling. Most Glow Worm boilers come with extended warranties and high energy efficiency ratings. The vast majority also feature benefits like frost protection.

But the real advantage over the competition is their focus on high-quality components. This is the reason you should choose them.

Glow Worms boilers, therefore, should be at the forefront of your mind when considering a new heating unit.

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