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Main Eco Compact 25kW or 35kW Combi Boiler

The Main Eco Compact Combi is perfect for small to medium-sized homes with one bathroom.

The Main Eco Compact Combi is a reliable gas-fired boiler that offers quality and efficiency at a price that’s hard to beat. It has compact dimensions to fit perfectly in a kitchen cupboard and it comes in a choice of outputs to match your heating and hot water requirements. If you’re looking for a budget-friendly boiler that can save you money on your gas bills, this well-made offering from Main could be the perfect combi boiler for your home and needs.

How Much Does this Boiler Cost?

To purchase the Main Eco Compact Combi, you need to spend between £515 and £540. These prices do include VAT but not the installation, which can set you back anything from £500 to £1,500. Combi boiler installation prices vary depending on whether you’re changing the type of boiler you already have or you want to move the boiler to a different spot in your home. Be sure to get a range of fixed-price quotes from local and national installers so that you can get the best replacement boiler installation deal.

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

The Main Eco Compact Combi is a combination boiler and can heat water directly from the mains, which means you won’t need any loft tanks or a hot water storage cylinder for the boiler to do its job. Since the Main Eco Compact Combi doesn’t require any additional components, it’s a good choice if your home has limited storage space. This boiler is also a good option if you have only one bathroom because combi boilers struggle to meet high hot water demand and can’t cope with multiple baths or showers running at the same time.

As the Main Eco Compact Combi comes in a 25kW or 30kW output, you need to determine which size is best for your requirements. As a general rule, the higher your demands, the higher the boiler output needs to be. It’s always a good idea to ask a Gas Safe registered engineer what size boiler they think best fits your home and needs.

Is it a High Efficiency Boiler?

It certainly is. The Main Eco Compact Combi is an Energy Saving Trust endorsed product and it’s A-rated for heating and hot water, with efficiency over 92%. It’s also Boiler Plus compliant and, if you get it installed, will save you money on your energy bills. But that’s not all. Main’s Eco Compact Combi features low NOx emissions and is rated class 5, so it’s kinder to the environment too.

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

Like we said before, the Main Eco Compact Combi is available with an output of 25kW or 30kW and both models have the same controls and features. These include a top central flue, rigid filling link, brass hydraulics block and an optional stand-off frame. There’s also a control panel at the front with a digital display, reset button, central heating temperature control, service diagnostic port, hot water temperature control and system water pressure gauge. What’s more, the Main Eco Compact Combi has ‘cupboard fit’ dimensions and is compatible with the Baxi uSense wired smart thermostat.

How long is the Warranty on this Boiler?

The Main Eco Compact Combi comes with a 5-year parts and labour warranty as standard.

Summary of Important Information

  • Expect to pay between £515 and £540
  • Heating output of 25kW or 30kW
  • Hot water flow rates of 10.2 or 12.2 litres per minute
  • Dimensions of 700mm (H) x 390mm (W) x 285mm (D)
  • Uses gas as its fuel source
  • A-rated for efficiency
  • 5-year warranty as standard

Pros and Cons

Whilst it’s important to consider quality and reliability when purchasing a new boiler, you can’t get away from the fact that the Main Eco Compact Combi is extremely cheap. This boiler is also energy efficient and it has some great features, plus the warranty is pretty good for a low-cost combi. Our only real niggle is that Main has a below-average Which? brand score, so you may want to look at the test results to see what engineers and customers are saying about this boiler before you make a decision.


  • Considerably cheaper than some other gas boiler brands
  • Suited to small and medium-sized homes
  • Compact cupboard fit
  • Easy to install, use and service
  • Boiler Plus compliant and Energy Saving Trust endorsed
  • Low NOx emissions – rated class 5
  • Provides maximum energy efficiency – reduce fuel bills and carbon emissions
  • Compatible with Baxi uSense smart thermostat – control heating via smart device  
  • 5-year warranty


  • Main has an overall Which? score of 48%
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