The Top 10 "Combi" Boilers

Written by nevillep
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The Top 10 "Combi" Boilers
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Combination boilers, which are a type of condensing boiler that heats and generates water on demand for taps and central heating from a single boiler unit, are often referred to as "combi" boilers in the United Kingdom. The unit combines both functions (water heating and central heating) in a compact unit. Moreover, it results in significant savings in water heating costs. Finally, installation of a combi boiler is simple since no tank is required, meaning less pipe work and a much shorter installation time.

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Halstead Eden CBX

The Halstead Eden CBX offers efficient hot water on demand, as well as environmental benefits like reduced CO2 emissions. The boiler comes in both 24kW and 32kW output sizes and has been given an "A" star rating by the Seasonal Efficiency of a Domestic Boiler in the UK database (SEDBUK). The boiler uses a stainless-steel, coiled heat exchanger to heat the water and digital technology for its diagnostic and programming needs. The unit is compact, with a digital display and a concealed user pad.

Viessmann Vitodens 200-W combi

The Viessmann Vitodens 200-W combi comes in a variety of output sizes (26kW, 30Kw and 35kW). The boilers have a stainless steel Inox-Radial plate-type heat exchanger for producing its on-demand hot water supply. The boiler is also available in natural gas and LPG form. The boiler is easy to install and maintain.

Worcester Bosch 37 CDi

The Worcester Bosch 37 CDi is made in Germany and comes in a white metal case. The boiler has a 9.2 gallons capacity and weighs 48.5 Kilogram. The boiler ensures hot water is received immediately and at water mains pressure, allowing the installation of a high-pressure shower without a pump and a cold-water storage tank. The boiler saves on heating costs by recycling heat from its exhaust gases. The heated water can maintain a temperature between 40 degrees C to 60 degrees C. The boiler has been rated 90.1 per cent efficient by SEDBUK.


The Saunier Duval ISOTWIN CONDENS F35E is a combi boiler that has been given an "A" star rating from SEDBUK. The ISODYN Shift Load storage system delivers up to 52.8 gallons of DHW. The unit is completely frost-protected and has zero compartment ventilation. The unit measures 74.8 Kilogram and has a threshold flow rate of 14 l/min. The unit, along with other Saunier Duval products, is a member of the HHCI and is recommended by the Energy Saving Trust (EST).

Vaillant ecoTEC plus 937

The Vaillant ecoTEC plus 937 comes with a large heating output that can generate huge quantities of hot water, making it highly suitable for large households. The boiler can store up to 52.8 gallons of hot water and comes with a large range of control accessories. The servicing and maintenance of the unit is simplified due to its single electronic circuit board. The boiler is a part of the SEDBUK "A" star team. The boiler uses very little energy and emits very few noxious gases, making it environmentally friendly. Moreover, the boiler has been awarded an "Energy Saving Recommended" logo from the Energy Saving Trust.

Keston C36 Combi

The Keston C36 Combi is a lightweight, compact boiler that allows full heating modulation, from 7kW to 27kW. The wall-mounted condensing boiler is has been given an "A" star rating by SEDBUK. The boiler is available in LPG and natural gas models. Moreover, they come with a 5-year heat-exchanger warranty.

Alpha CD25C

The Alpha CD25C is energy efficient, and has a streamlined, smooth design, and the hydro-block boiler saves space by requiring fewer pipe connections. The boiler has easy-to-control features and simple temperature controls under a protective flap.

Baxi Duo-Tech Combi HE A

The Baxi Duo-Tech Combi HE A design is available in 4 different output models (24, 28, 33 and 40kW) to suit all property sizes. The maximum flow rate is 16 l/min. The boilers are classified in the top-rated category by SEDBUK, as more than 90 per cent of the fuel utilised by the boiler is converted into useful heat. The boilers are designed with a white glossy finish, are compact and have simple user-friendly controls.

Ravenheat CSI 120 Low NOx

This combi boiler is a highly functional unit that has been designed to reduce NOx levels and reduce energy costs. The CSI 120 Low NOx can provide high volumes of water with up to 13 l/min at 35 degrees C. The boiler also has a full modulation fan and burner with valves and a patented heat exchanger.

Ferroli Optimax HE31 C

The Ferroli Optimax HE31 C is a part of an extensive range of combi boilers by Ferroli. The boiler provides on-demand heating for households. The 31kW boiler has a high flow rate of up to 12.6 l/min. The unit is available in both LPG and natural gas installations and comes with 5-year guarantee.

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