If you’re looking for the best condensing boiler money can buy, this post may be useful. Before we get into the boiler comparisons and reviews though, if you’re new to this, let’s first understand what a condensing boiler actually is.
Before we begin though, we’d like to clear some of the confusion around condensing boilers, as clients have asked us if condensing boilers are combi boilers. The following post explains this in detail: Condensing or Combi Boiler
In short, all boilers manufactured in 2019 are condensing boilers, doesn’t matter which configuration, whether Open Vent, Sealed System, or Combi.
What is a Condensing Boiler?
And how do they work?
All boilers, whether non-condensing or best condensing boiler, have combustion emissions, like heated gases, pass through their heat exchangers, transferring the energy that’s generated to radiators or under-floor heating, which spreads heat around your house. After this is done, the remaining combustion gases are released into the air outside through the flue, usually up through the roof or through the wall.
In older, non-condensing boilers, some portion of this heat is lost during this process, because along with the waste gases a large amount of steam that forms during the burning process (due to the water contained in natural gas in its initial state) is being pushed out. The released steam carries an untapped amount of evaporation energy, that older, non-condensing boilers are unable to make use of.
Whether you buy a cheap or the best condensing boiler manufactured in 2018, it will recycle the water vapour through their primary heat exchangers, recovering latent heat of vaporisation. This condensed vapour leaves the system in liquid form, via a condensate pipe into a drain.
Energy Efficiency: 90% to 92%
Approx. Price (Boiler Only): £1,400 inc. VAT
Approx. Price (Boiler + Installation): £3,000 inc. VAT
One of the reasons why Vaillant and Worcester Bosch don’t score higher than Viessmann is because they still choose to use aluminium for their heat exchangers, instead of stainless steel. This attempt from Vaillant in the best condensing boiler space has its merits. It’s a high efficiency boiler and their lowest fuel consumption model. Vaillant also claim 85% of its parts are recyclable at the end of its life. This boiler can be programmed and controlled from your smartphone or tablet as well.
- Quiet operation
- Flow rate of 17.8 litres per min for fast instant hot water
- ErP A rated for both hot water and heating efficiency
- Dimensions in mm (43kW): W 720 x H 440 x D 474
- Works with LPG where required
Energy Efficiency: 89% to 90%
Approx. Price (Boiler Only): £900 inc. VAT
Approx. Price (Boiler + Installation): £2,200 inc. VAT
Viessmann’s entry level model in the best condensing boiler arena, it has surprisingly good performance at an incredibly affordable price. What’s more, it has the same patented Viessmann stainless steel heat exchanger, and is also compatible with weather compensation. And although it starts off at around 90% efficiency, with programmable thermostats and weather compensation it can go up to 92% to 94% efficiency, which is mighty impressive for its price.
- Ultra Compact – Just 707mm in height
- DHW output ratings of 5.9 to 35 kW
- High quality stainless steel Inox-Radial heat exchanger
- Integral instantaneous water heater
- High efficiency – up to 97% (Hs) [gross cv]
- Low CO2 emissions for reduced environmental impact
- Digital user interface with LCD display for easy operation
- Optional room thermostats, plug in time clock and wireless receiver
- Up to 7 year extended warranty available
- Class A rated for energy efficiency