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Glow-worm Energy Combi Boilers 25kW, 30kW or 35kW

energy combi

The Glow-worm Energy Combi is a Quiet Mark approved combination boiler that comes in a good range of heat outputs.

This gas condensing combi boiler by Glow-worm is super-quiet and features sophisticated components for long life and excellent performance. It’s a rather small and sleek appliance with minimal casing to enable the boiler to fit inside a kitchen cupboard or be installed almost anywhere else. Better still, the Energy Combi provides hot water and central heating without the need for a hot water storage cylinder or cold water tank.

How Much Does this Boiler Cost?

The Glow-worm Energy Combi comes in an output of 25kW, 30kW or 35kW and will cost you anything between £790 and £920. In addition to the boiler cost, you’ll need to consider installation as well. Because boiler and fitting costs vary, we suggest you shop around in order to find the best price for both. By comparing prices, you could end up saving yourself a few hundred pounds.

How will I know if this Boiler is Suitable for My Home?

As the Glow-worm Energy Combi is a combination boiler, it doesn’t require any separate cylinders or tanks to store water and is, therefore, a great option for homes where space is limited. The only slight downside to combi boilers is that they struggle to provide a constant supply of hot water to multiple taps that are running at the same time, but this won’t be a problem if you have just one bathroom or smaller hot water requirements.

To find out if this boiler is the perfect fit for your home, you’ll need to consult a Gas Safe registered engineer. A professional will also be able to work out which size (kW) of boiler is suitable for your needs, helping you to choose between the 25kW, 30kW or 35kW Glow-worm Energy Combi.

Is it a High Efficiency Boiler?

We’re pleased to report that this boiler has a seasonal efficiency of 89.2% and is ErP A-rated. So, if you go on to replace an old inefficient boiler with the Glow-worm Energy Combi, you’ll reduce carbon emissions and save some cash on your annual fuel bills. Even though this all sounds great, the boiler can actually help you to achieve even greater savings when used with an optional intelligent control, such at the Climapro2 RF control or the MiGo app-based personal heating assistant.

Does this Boiler have a Good Range of Controls and Features?

Glow-worm’s Energy Combi is a user-friendly boiler that comes complete with a system pressure gauge, reset and on/off switches and adjustable heating and hot water temperatures controls. Like we just said, you can use some optional controls too. Many homeowners that purchase this boiler opt for the MiGo because it has the intelligence to learn your energy needs and lets you control your heating and hot water from your smartphone. When it comes to features, it has a bright interface and an aluminium heat exchanger that helps to prolong the boiler’s life. The boiler also has a modulating Grundfos pump, meaning it can adapt its output to meet demand and keep running costs low.

How long is the Warranty on this Boiler?

The boiler comes with a fantastic 7-year parts and labour warranty as standard. Get a Glow-worm Club Energy installer to fit the boiler, and you’ll be offered an extended guarantee of up to 15 years.

Glow-worm Energy Combi Prices and Sizes

ModelTypeDimensionsMaximum Flow RateOutputEfficiency RatingTypical Price
Energy Combi 25CombiH – 700 mm
W – 390 mm
D – 280 mm
12.1 l/min25 kWA 90% and above£790
Energy Combi 30CombiH – 700 mm
W – 390 mm
D – 280 mm
14.2 l/min30 kWA 90% and above£850
Energy Combi 35CombiH – 700 mm
W – 390 mm
D – 280 mm
16.5 l/min35 kWA 90% and above£920

Summary of Important Information

  • Priced between £790 and £920
  • Heating output of 25kW, 30kW or 35kW
  • Hot water flow rates of 12.1, 14.2 or 16.5 litres per minute
  • Dimensions of 700mm (H) x 390mm (W) x 280 (D)
  • Uses gas as its fuel source
  • A-rated for efficiency
  • Smart compatible
  • 7-year warranty as standard

Pros and Cons

Glow-worm is well-known for developing great value boilers that provide great energy efficiency and a lower carbon footprint, such as the Energy Combi. But we think this one really stands out because it can be made even smarter and has a generous warranty. To find out all the pros and cons of this boiler, just look below.


  • Fits in a kitchen cupboard
  • Suited to small, medium and large-sized homes
  • No need for separate cylinder or loft tanks
  • Easy to use and service
  • Quiet Mark approved
  • Grundfos pump – reduces energy use and fuel bills
  • High-grade aluminium heat exchanger – reliable performance
  • Provides maximum energy efficiency – reduce fuel bills and carbon emissions
  • Compatible with a range of intelligent controls – improves efficiency and performance
  • Compatible with the MiGo app-based control – maximises efficiency, learns your energy needs and allows you to manage your heating and hot water from anywhere
  • 7-year warranty


  • Glow-worm boilers have an overall Which? score of 54%
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