Combi Boiler Heating Systems

Combi's are now the most used form of central heating boilers - especially in flats. Most Combi's run on mains pressure water, thus do not require tanks to be placed in the loft. They also eliminate the need for a hot water cylinder as they instantly heat the water when it is needed. Another benefit with the combi is that, due to it running from the mains water supply, you can create an effective power shower without the need for a pump.

Combi boilers require the least amount of plumbing thus offer a cost saving when installing.

Advantages of a Combi Boiler Heating System

• No tanks or cylinder to occupy space or maintain
• Hot water is pressurised and always available
• Cost effective solution for new installations as less in required
• Hot water is a sealed circuit avoiding contamination
• Heating circuit for the radiators is sealed avoiding contamination
• High Efficiency Condensing versions are available
• The pressure gauge for the central heating will detect leaks

Disadvantages of a Combi Boiler Heating System

• Poor in areas with poor water pressure
• Rarely suitable for houses with 2 or more bathrooms
• Doesn't store water in a loft tank should there be a shortage
• As the central heating is under pressure there may be a chance of older systems leaking
• Combi's are slightly more complicated and maintenance may cost more over the long run
• May be more expensive to install in a home that have a Conventional or System boiler layout previously.

Selecting a Combination Boiler

Once you have decided that a Combi system is best for you, you then can decide on a boiler.

We recommend a condensing boiler from one of the 2 boiler manufacturers:

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• 

We recommend these manufacturers for their:

• Quality
• Reliability
• Comfort
• Customer care
• Value

Two other manufacturers that rank highly and may have appeal for those on a budget are:

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Combination boilers

Make	Model	Power	Warranty	Controls	Size (mm) HxWxD	Litres of hot water per minute (35 deg)
Worcester-Bosch	Greenstar 27CDi	27kW	2 years	Central Heating, Hot water, Display	760x440x360	11
Worcester-Bosch	Greenstar 30CDi	31kW	2 years	Central Heating, Hot water, Display	760x440x360	12.6
Worcester-Bosch	Greenstar 37CDi	37kW	2 years	Central Heating, Hot water, Display	760x440x360	15.1
Worcester-Bosch	Greenstar 42CDi	42kW	2 years	Central Heating, Hot water, Display	760x440x360	17.1
Worcester-Bosch	Greenstar 25Si	25kw	2 years	Central Heating, Hot water	710x400x330	10.2
Worcester-Bosch	Greenstar 30Si	30 kw	2 years	Central Heating, Hot water	710x400x330	12.3
Worcester-Bosch	Greenstar 24i junior	24 kw	2 years	Central Heating	710x400x330	9.8
Worcester-Bosch	Greenstar 28i junior	28 kw	2 years	Central Heating	710x400x330	11.4
Worcester-Bosch	Highflow 440	29.2 kw	2 years	Central Heating, Hot water	850x600x600	20
Vaillant	Ecotec Plus 824	23 kw	2 years	Central Heating, Hot water, Display	720x440x335	9.4 / 7.9 for 42 deg rise
Vaillant	Ecotec Plus 831	31 kw	2 years	Central Heating, Hot water, Display	720x440x335	12. / 10.6 for 42 deg rise 7
Vaillant	Ecotec Plus 837	37 kw	2 years	Central Heating, Hot water, Display	720x440x403	15.2 / 12.6 for 42 deg rise
Vaillant	Ecotec Plus 937	37 kw	2 years	Central Heating, Hot water, Display	720x440x597	20.4 at a 30 deg rise / 15.2 at 65 deg
Vaillant	Ecotec Pro 24	23 kw	1 year	Central Heating, Hot water, small Display	720x440x335	9.4 / 7.9 for 42 deg rise
Vaillant	Ecotec Pro 28	28 kw	1 year	Central Heating, Hot water, small Display	720x440x335	11.5 / 9.6 for 42 deg rise
Alpha	CD25C	24.3Kw	3 / 5 years	Central Heating, Hot water, LEDs	720x440x340	9.6
Alpha	CD28C	28.7Kw	3 / 5 years	Central Heating, Hot water, LEDs	720x440x340	11.4
Alpha	CD35C	34.6Kw	3 / 5 years	Central Heating, Hot water, LEDs	720x440x340	14.2
Alpha	CD50C	29.7Kw	3 years	Central Heating, Hot water, LEDs	720x440x490	18
Alpha	CD25X	24.3Kw	2 years		720x440x340	9.6
Alpha	CD28X	28.7Kw	2 years		720x440x340	11.4
Baxi	Combi 105HE	29.6kW	1 year	Central Heating, Hot water, LEDs	780x450x345	12.1
Baxi	Instant 80HE	25.2kW	1 year	Central Heating, Hot water, LEDs	780x450x345	9.8
Baxi	Instant 105HE	31 kW	1 year	Central Heating, Hot water, LEDs	780x450x345	12.1
Baxi	DuoTec24	24 kW	2 years	Central Heating, Hot water, LEDs, Display	780x450x345	9.8
Baxi	DuoTec28	28kW	2 years	Central Heating, Hot water, LEDs, Display	780x450x345	11.5