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Glow-Worm Boiler: Review and Comparison With Worcester Bosch

If you’re looking for a new boiler and aren’t quite sure where to start, our guide to Glow-Worm boilers and the best alternatives is going to help you out.

Below we’ll cover Glow-Worm prices, warranties, reviews, and how they stack up when compared directly to Worcester.

Glow worm boiler review

Who are Glow-Worm?

Glow-Worm have been manufacturing boilers since 1934 and now produce a full range of combi boilers, heat-only boilers, and system boilers.

Since 2001, they’ve been owned by one of the most reputable boiler brands in the UK; Vaillant. But, there’s no doubt that the Glow-Worm brand lags leading industry players such as Worcester, Baxi, Potterton and in fact, even Vaillant.

Glow-Worm Boiler Prices — Boiler Only

How much does a boiler from Glow-Worm cost?

Typically, they’ll be in the low-mid range when compared directly with a brand like Worcester Bosch or Baxi.

As an example, you’ll be able to pick up the Ultimate 3 30kW for around £800 (boiler only). And, for a boiler with a 10-year manufacturer’s warranty, that’s a good deal.

Compare that with a Worcester Greenstar 4000 combi boiler, which is likely to cost around £1,200. Naturally, that’s going to make a difference of around £400 to the overall cost of installation, considering the two boilers are installed by a local heating engineer.

Comparing Glow-Worm Boiler Prices vs Worcester Bosch

However, mid-tier brands like Glow-Worm are now competing against online boiler installers that offer fixed prices, thanks to their ultra-low overhead.

The end result:

A local Gas Safe installer fitting a boiler from Glow-Worm may quote you as much as Heatable fitting a Worcester Greenstar 4000.

You can compare the two by getting quotes from local installers. And, you can then jump onto Heatable and fill out their 90-second form to get a fixed online quote (no personal details needed).

Worcester Bosch Greenstar 4000

Glow Worm Boiler Warranty Periods

As you may have noticed above, we’ve picked the Ultimate 3 boiler for example’s sake. And, that’s mainly due to the fact that there’s a 10-year warranty on offer, comparable to the Greenstar 4000.

If you’ve read our other boiler reviews, you’ll know we never recommend a boiler that comes with less than 2-years warranty, and we prefer 5+, and you’ll get 10 straight up with Worcester here.

The fact is, the boiler makes up around 50% of the installation cost. So, if it fails, it’s not simply a case of buying a new boiler, you’re paying for labour all over again.

And, we think manufacturer’s warranties are a good indication of what the brand thinks of their product, in terms of longevity.

Typically, there’s little more than a few hundred pounds difference between the lowest and highest priced boilers in a brand’s range. Essentially, you’re getting great value for money by heading for a boiler in the 5-10 year range rather than one with a 2-3 year warranty.

Glow Worm Boilers Warranty Table

If you’re looking for a boiler from Glow-Worm, the most popular come with the following warranties:

Boiler Warranty
Glow-Worm Energy 7-years
Glow-Worm Ultimate3 10-years
Glow-Worm Betacom 4 5-years
Glow-Worm Easicom 6-years
Glow-Worm Essential 3-years

Glow Worm Brand Reputation

Put simply, Glow-Worm is the budget arm of Vaillant Group. And, as with everything in life, you get what you pay for.

Our opinion is to go for a boiler with the highest warranty possible (so the Energy or Ultimate3 Glow-Worm combi boilers), or to stick to well known brands including Baxi, Potterton, Vaillant and Worcester Bosch. Given you can probably get a Worcester here at the same price, that would be what we’d be doing.

Glow Worm Reviews

So, we tend to head for the leading brands in the industry, but we’re not completely against Glow-Worm. And, there are plenty of people that rate Glow-Worm as a brand. The reviews on Trust Pilot are a combination of homeowners and installers, rating customer service, through to product quality.

And overall, the reviews are good. Currently, the review rating on Trust Pilot is 4/5 stars, with over 1,500 being logged so far:

Glow-Worm vs Worcester Bosch Equivalent

With Worcester typically being around £200-250 more expensive from local installers, there used to be a difficult decision to made. Do you go with a lesser known brand to save the cash, or pay the extra for one of the most reputable brands in the industry?

Why We’d Choose a Worcester Over a Glow Worm

Thanks to Heatable’s online business model and low overhead, you’ll be able to get a Worcester Bosch equivalent fitted for a similar price, and get savings of up to £1,000 when compared with national installers.

So, our choice? Get a quote from Heatable for a Worcester Bosch boiler (no site visit or personal details needed). And, if you’re still not sure, get an on-site visit from local installers, comparing to the fixed price online from Heatable.

Heatable boiler installations

FAQs About Glow-Worm Boilers

On a final note, we’d like to address a few of the questions we often hear about boilers from Glow-Worm.

How long do Glow-Worm boilers last?

With proper care — such as annual boiler service, magnetic, and limescale filters — a Glow Worm can be expected to last up to 15 years. However, being a budget brand, you should be careful and choose the best boiler model; preferably those covered by a long warranty term.

Are Glow-Worm good boilers?

Glow-Worm manufacture decent boilers, especially for a low-cost brand.

Generally, they’re made with quality parts, like the Grundfos high-efficiency modulating pump and an automotive grade aluminium heat exchanger (similar Worcester’s).

If you’re looking for a Glow-Worm combi boiler, consider the Ultimate3; it features reliable components, high energy efficiency, and a long, 10-year warranty.

Glow-Worm system boilers tend to have a shorter warranty period than their combi boiler models, but if it’s a system boiler you need, the Glow-Worm Energy system boiler is the one you should consider. It’s efficient and compact (i.e. you can fit it into a kitchen cupboard), and it comes with a 7-year warranty and an option to extend it.

Are Glow-Worm boilers energy efficient?

Yes, Glow-Worm boilers meet and exceed the efficiency standards to which modern condensing boilers are manufactured. Some models, like the Ultimate3, boasts an energy efficiency of 94%. This means that replacing your non-condensing, G-rated boiler with a new Glow-Worm will help you save on your energy bills.

What temperature should my Glow-Worm boiler be set at?

Like any other condensing boiler, a modern Glow-Worm will be most efficient when the return temperature — the temperature of the water coming back to the boiler — is 54°C degrees or less. To achieve this return temperature, you should set your boiler flow temperature to about 65°C. That’s lower than the 75°C many households are used to, but you should see an improvement in the boiler’s energy efficiency and a reduction in your gas consumption.

Note that for domestic hot water, the temperature should be higher than 60°C.

Is Glow-Worm the same as Vaillant?

Glow-Worm are the budget arm of the Vaillant Group. So, whilst the two brands have the same parent company, the quality of Vaillant boilers is superior to Glow Worm.

What’s Next?

Thanks for reading our guide covering Glow-Worm boilers. Hopefully, there’s enough information there for you to decide which boiler you should get to serve your central heating and hot water.

We regularly post fault-finding guides and reviews, so bookmark this page and pop back soon.

Or, if you have a question you’d like to ask, leave us a comment below and we’ll get back to you as soon as we can.

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