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Gas System Boilers For Heating and Hot Water

High-Efficiency Sealed System Boilers from Glow-worm

A Glow-worm system boiler is ideal if you have high demand for hot water from multiple sources at once in your home, or you have limited space in your loft., Our dependable, high-quality gas system boilers will ensure that you’re never caught short.

As the pioneers of heating in the UK, we are proud to offer a wide range of high-efficiency sealed system boilers, lowering energy bills for homes of all sizes. Choose a Glow-worm appliance for reliable hot water and central heating for years to come.

To get started, simply click on one of our system boilers below to learn more about the product and its suitability for your home. Need a little help? Don’t hesitate to contact us online, or give our friendly team a call on 0345 602 2922 and we’d be happy to answer any questions you might have.

*Please note: Our extended guarantees are available when installed and registered by a Club Energy installer. Find an installer near you to take advantage of this offer.

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Quiet Mark Approved

Energy system boilers

ErP A rated compact system boiler

  • Compact size will fit perfectly in kitchen cupboards
  • ErP A rated for efficiency - helping you to reduce your energy bills
  • Quiet Mark approved*

Ultimate₃ System Boiler

High efficiency sealed system boiler from Glow-worm

  • Highly reliable system boiler offering outstanding performance
  • ErP A rated for efficiency – helping you to save money on your energy bills
  • Up to 10 years guarantee*

Easicom₃ System Boilers

Quality, reliability, choice

  • FREE 3 year guarantee with option to extend*
  • ErP A rated for efficiency – helping to lower your energy bills
  • Manufactured right here in the UK by Glow-worm, the brand you can trust

Flexicom sx (Discontinued)

The Compact System Boiler from Glow-worm

  • High efficiency with a NOx class 5 rating
  • The only condensing system boiler with a direct flue
  • Could be fitted almost anywhere

Ultracom₂ sxi (Discontinued)

The Prime System Boiler from Glow-worm

  • No need for a cold water tank in your loft
  • LPG compatible without separate conversion kit
  • Sleek and attractively designed

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What is a system boiler and how does one work?

System boilers provide central heating and hot water via a storage cylinder. They work like a regular, or conventional, boiler in that they store hot water at the right temperature ready for you to use. Unlike a regular boiler, they take their water supply from the mains so there’s no need for a separate water tank in your loft. This not only frees up valuable space in your loft, but also means that we can offer a more efficient and cost-saving installation process.

If you’d like to learn more, check out our comprehensive guide to system boilers.

Should I buy a system boiler?

We recommend buying a system boiler if your household needs hot water from several bathrooms or outlets at the same time. They’re also ideal if you don’t have much room in the loft (or would simply like to save space). What’s more, gas system boilers are highly energy-efficient, and they’re cheaper and easier to install than regular or heat-only boilers.

All the same, homes with limited space and low hot water demand might be better off with a combi boiler, as these don’t require a separate storage cylinder in your airing cupboard. If you have low water pressure or old-fashioned radiators but still need lots of hot water, then a regular boiler is the best option.

Still unsure if a system boiler is suitable for your home? See our system boiler guide for more information to help you decide.

Which type of system boiler is right for my home?

You’ll find a selection of different Glow-worm sealed system boilers to choose from above. When buying a system boiler, consider the size of your home and the number of bedrooms and bathrooms to help you pick the right model:

  • One- or two-bedroom homes with up to two bathrooms will benefit from a highly efficient 12 or 15kW Energy system boiler, although an 18kW Energy system boiler would be more suitable for smaller households that tend to use a lot of hot water at the same time.
  • Our industry-leading Ultimate₃ System Boilers and Easicom₃ System Boilers offer a 25kW output, making them the ideal choice for a three- or four-bedroom home with several bathrooms.
  • If your home has five or more bedrooms and multiple bathrooms, then we’d recommend a powerful 30kW Energy system boiler.

Glow-worm system boiler guarantees

Our free parts and labour guarantees are some of the best on the market, with the Energy System Boiler having a 7-year guarantee out of the box. See the individual products above for more information on their guarantee periods.

It’s also possible to extend the length of your guarantee if you have your Glow-worm appliance installed and registered by a Club Energy installer. Find an installer near you when you buy a system boiler to take advantage of this offer.