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Energy combi boiler

Free 7 year warranty through Club Energy

  • Rear flue option
  • Free 7 year warranty* with option to extend
  • High quality, automotive grade, aluminium heat exchanger
  • High efficiency, modulating Grundfos pump
  • ErP A rated for efficiency - helping you to lower your energy bills

Feel the Energy at the heart of your business

Glow-worm’s Energy combi boiler is designed to bring the power of connectivity to you. It’ll connect you to your business, customers, and Glow-worm.

Compact, efficient & high quality boiler range

Designed using automotive grade aluminium, the Energy heat exchanger is a high quality, high efficiency product that makes the boiler light to install. The Energy combi boiler is compact and comes with a rear flue option, making it ideal for a cupboard fit.

The Energy combi boiler comes with a great range of outputs, attractive modern design, bright easy-to-use interface and a choice of controls.

All it requires is simple water flush cleaning for the heat exchanger, which means lower costs and no special cleaning tools. The patented 4 sided cooling reduces the stress on the heat exchanger, which means longer term reliability for your customers. Energy is supported by UK wide spare parts availability.

Work with Plumbing Toolbox for an easier way to install

Club Energy members can use our industry leading Plumbing Toolbox app to make their installations even easier. They can complete the registration, warranty, Gas Safe notification and Benchmark on the go saving a lot of time. Club Energy members are also eligible for rewards on their boilers and can offer their customers up to 15 years of warranty. Find out more about Club Energy here.

*When registered through Club Energy

Features & benefits

  • Wide product range allows Glow-worm's Energy boiler to cater for every heat output demand and every system requirement
  • Rear flue option gives flexibility to the Energy boiler, meaning it will fit almost all install situations
  • High quality, automotive grade, aluminium heat exchanger designed to last longer, be easy to maintain, is super quiet and reduces customers’ energy bills
  • Offers the choice to install in more locations including a kitchen cupboard
  • Modern, bright, LCD display shows excellent clarity of boiler information wherever it is installed, making it easy to change and confirm settings
  • High efficiency, modulating Grundfos pump resulting in lower running costs as the pump adapts to actual heating and hot water demand



Energy combi boiler range25kW30kW35kW
Casing dimensions (H x W x D mm)700 x 390 x 280700 x 390 x 280700 x 390
x 280
Weight (lift) (kg)323233
CH output minimum/maximum (kW)5.0/18.36.1/25.47.2/25.6
DHW output (kW)25.730.635.7
DHW flow rate (35°C rise) (l/min)10.412.514.4
Minimum operating pressure (bar)
Minimum pressure for maximum flow1.01.01.0
SEDBUK 2009 annual efficiency (%)89.389.389.2
ErP rating heatingAAA
ErP rating DHWAAA
NOx class (natural gas)555
Heat exchanger materialAluminiumAuminiumAluminium
Burner typeDownward firingDownward firingDownward firing
Fully modulatingYesYesYes
DHW Plate heat exchangerStainless steelStainless steelStainless steel
Integrated hydroblocYesYesYes
Suitable for sealed systemsYesYesYes
Filling loopIntegratedIntegratedIntegrated
Inbuilt system bypassYesYesYes
Inbuilt condensate trap/siphonYesYesYes
Inbuilt frost protectionYes YesYes
Zero compartment ventilationYesYes Yes
Pump typeGrundfosGrundfosGrundfos
Top (mm)150150150
Side (mm)0.5*0.5*0.5*
Bottom (mm)150150150
Front (mm)600**600**600**
User interface
User adjustable CH temperature controlYesYesYes
User adjustable DHW temperature controlYesYesYes
Warm start functionYesYesYes
Optional spacing frame - 0020193660YesYesYes
Plug in mechanical timer - 0020095196OptionalOptionalOptional
Aesthetic pipe cover - 0020193659YesYesYes
Optiflue compatible (PEGHRD) - 0020152034YesYesYes
Maximum horizontal Ø60/100 (m)101010
Maximum vertical Ø60/100 (m)101010
Maximum horizontal Ø80/125 (m)252525
Maximum vertical Ø80/125 (m)252525
Optional plume management kit Ø60/100YesYesYes
Direct rear flue optionYesYesYes

*See manual for clearance if side panels are to be removed to assist future service and maintenance

**5mm if removable panel/door

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Alternative products

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Ultimate₃ combi boiler

Exclusive combi boiler with 5 years warranty*

  • Leading combi boiler offering great performance
  • FREE 5 year warranty* with option to extend
  • £15 reward when registered through Club Energy
  • Available in 30kW and 35kW models