Combination boiler or combi boilers are the most commonly
used type of boilers which are very famous in UK for a reason. Unlike the
system and conventional boilers which requires a hot storage cylinder, the
combination boiler comes as an all in one unit which produces hot water for
taps and central heating. Not only this, it saves a great space in your homes
and its installation is easy and faster comparative to any other boiler.
It usually takes the water from the main supply and provides
stronger water pressure. It delivers plenty of hot water. Thus, no longer waits
for the tank to refill again and again.
Modern high efficiency unit boilers are the stainless steel
condensing boilers with its built-in heat exchanger to provide hot water to a
home or a building. During the cold season, usage of combi boiler increases as
it provides hot water for heating the surfaces. Therefore, in hot summer days,
combi boiler works as per the domestic hot water requirement.
The two main reasons behind the combi boilers great and
powerful efficiency is that, these units have high operating efficiency and low
internal water volume. This means when in summer days you don’t need space
heating you are only paying for the heat of hot water which is domestically
What is a condensing boiler?
Majority of new generation combi boilers are condensing
boilers. Earlier in the non- condensing boilers, Flue Gas Heat System was not
installed. In past any boiler which works, produces flue gases and heat and the
produced gas and heat gets wasted in these non-condensing boilers.
A Flue Gas Heat System captures the heat from these flue
gases and recycles it to preheat the new cold water as it enters to the boiler
from mains. Therefore, this saves lot of energy as the boiler doesn’t need to
work again and again to heat the water.
Condensing boilers have become a common alternative to
non-condensing boilers in boilers marketplace. Condensing boilers work with
high-temperature systems, still more efficient than any other boiler.
Condensing boiler efficiency multiplies when used with lower water temperature.
Now you might be thinking which best boilers combi
Here are top three best combi condensing boilers with all
their specifications and features.
Worcester Bosch Greenstar 25i
one of the best-selling combi boiler from one of the leading brand Worcester
Bosch. This brand has become a household name for their continuous
manufacturing of up-to-date boilers.
Greenstar 25i Boiler manufactured by Worcester Bosch has a high ErP(Energy
related product) with the rating of 93% efficiency rate. It is the perfect
successor for 24i junior. These wall mounted boilers are designed for the
apartments or flats having 1 or 2 bedrooms with 1 bathroom. Although it looks
very similar to the other combi boilers of Worcester Bosch but its new magnetic
flap opens to reveal the brand new layout. This unit includes increased
outputs, higher hot water flow rates, a user friendly control panel and a
larger condensate siphon that eliminates the risk of condensate freezing.
model has been designed to make installation and commissioning easier and
quicker than before. Whereas the unique wall mounting feature enables the
installer quick pre-plumb all the seven pipe connections without the boiler
being on the wall.
feature retains the fantastic features of 24i with the added benefits and
features. This boiler can fit into a standard kitchen cupboard so that it
couldn’t take much of space. Central heating flow and hot water can be adjusted
using simple control knobs and the clear information can display.
User friendly control – There is an immense variety of
controls to choose from, range from mechanical to smart options. You will
surely expect the control panel once you have opened the flap on the Greenstar
25i. The most amazing thing about the control of this unit is that you can
manage your heating and hot water from your smartphone app, isn’t it amazing?
Eliminates condensate freezing – This unit has been tested
under stimulated under extreme weather condition and proved its effectiveness
in preventing frozen condensate at -15 degree Celsius for a sustained period of
Efficient – the Worcester Greenstar Bosch
25i lives up to its name as a “green” boiler. With the highest ErP(Energy
related Product) of 93% this is high performance boiler. Also you will save
money on those monthly energy bills.
Warranty – Worcester bosch offers standard
warranty of 5 years free of cost to every user.
Weather compensation option – The Greenstar 25i comes up
with a weather compensation sensor that has been built to outlast all weather
conditions and mark an addition to the efficiency level of the product that has
already touched the grounds.
depth – 330 mm
height – 710mm
width – 440mm
type – LCD
output – 25kW
type – Natural Gas
– 5 years
rate – 12.3
conclusion, the Worcester Bosch Greenstar 25i combi boiler is the perfect
choice for a flat having 1-2 bedrooms and 1 bathroom. With one of the highest
efficiency this boiler stands out with its high performance.
Greenstar boiler has won the prestigious Which? Best Buy award for 7 continuous
years which simply signifies the quality of the company’s product. With lots of
benefits and improvement this Greenstar 25i is the successor for Greenstar 24i
The Greenstar Highflow 440CDi Floor standing boiler is the
new and exclusive range of Worcester and has been developed for larger two
The Worcester Greenstar Highflow 440CDi floor standing combi
boiler has been designed for the properties with large number of radiators and
high demand for instant hot water. The higher outputs of this unit make it
suitable for larger properties with multiple bathrooms.
This Greenstar combination gas boiler is SEDBUK band A rated
gas boiler and also offers range of unique features that allow easier and
quicker installation of the boiler. Also the operating features of wall-mounted
combis can be used for mechanical, digital, wireless and new-generation
intelligent controls. The Worcester combi boiler now comes with a unique 4.5
meters condensate pump that is fitted as standard.
Now you can control the both hot water and heating
temperature as it offers 180l domestic hot water at an average of 35 degrees C
rise at flow rates up to 25l/min. Isn’t it great? This unit offers the widest
choice of operating features with the ultimate user convenience, performance
and fuel economy. This boiler is highly recommended by the Energy saving Trust
Hot water performance – the Greenstar
Highflow 440CDi combi boilers are well known for their industry leading hot
water flow rates up to 25litres per minute. Without the need for a separated
storage tank, this unit is able to deliver comparable flow rates to systems. As
a result the tank can refill immediately and showers can be taken for longer
period of time. Its separate plate heat exchanger and thermal store ensures the
instant availability of hot water to its user.
Clean burning combustion – the Worcester
WB5 heat exchanger has been designed and developed to optimize clean burning
combustion over an extra area. Each heat exchanger has been tested so, as the
gas inlet pressure is correct. The heat exchanger requires minimal servicing
i.e. can work for a longtime. It can be cleaned in-situ with an inspection
hatch, therefore saves time during the service.
Customized controls- a choice of
optional controls is offered by the Greenstar Highflow 440CDi combi boiler to
select the type of control which best suits its user requirements. The choice
ranges from a simple-to-operate digital programmer, to sophisticated wireless
programmer. Also, the room thermostat
and intelligent controls includes Wave
smart control as well.
Premium quality – every
Greenstar Highflow CDi boiler is operationally tested before it leaves the
factory as a part of Worcester’s quality performance.
Efficient – the Worcester
combination boiler is very much efficient as it is SEDBUK BAND A rated boiler.
Also it is fully ErP(Energy related product) compliant with 92% rate of
Fluing Option – this
combination boiler has a full range of condensfit flue options in both 60/100
mm and 80/125mm diameters and includes a plume defector as standard. This
versatile flue system can be moved horizontally as well as vertically. Also
this multi-directional fluing allows the boiler to be sited in a wider variety
Boiler height – 850mm
Boiler depth – 600mm
Boiler width – 600mm
Boiler weight – 66.0kg
Warranty – 5 years
Flow rate – 20l/min
Power output – 29kW
Fuel used – Natural Gas
This Greenstar Highflow 440CDi has been manufactured from one
of leading boilers company Worcester which has always stood up to the
expectations of its customers with user friendly features and variety of
additions. This Greenstar combi boiler is the best choice for the people who
have 2-3 bedrooms and 2 bathroom house.
With its unique features and free-standing model it is one of
the most recommended boiler for semi-detached houses. Even, Energy Savings
Trust also recommends this boiler which means you will be doing your part to
save the environment with the purchase of this free-standing combi boiler.
Vaillant ecoTEC 835 combination boiler
Attaractive in design and quiet in operation, this boiler
delivers superb performance using Vaillant AquaComfort system. This Vaillant
ecoTEC combination boiler is suitable for large properties.
Vaillant ecoTEC 835 combination boiler is a choice for all the large properties
due to the increased flow rate and output. The Vaillant is Europe’s second
largest boiler manufacture. It offers high quality and polished energy
no hot water cylinder and water tank in the loft, this combination boiler by
Vaillant provides you almost instant hot water supply to your taps and can fit
into any corner of your house with limited space. Vaillant combi boilers are
highly efficient and deliver a top SEDBUK Band ‘A’ rated fuel efficiency and
powerful DHW performance. It offers premim components for outstanding
performance, quality and the best heating to your homes. This boiler has an ERP
rating A, also it comes with frost protection, keeping it protected from
innovative new flame lit detection system will help you to monitor the low
combustion and noise with optimized burner settings. Also it comes with assured
comfort that there is a back-up mode so in case of a fault with the combustion
boiler, it will able to revert to the last known operating system.
User-friendly controls – alike every other combi
boiler, this boiler also has the control panel behind the flap which allows you
to do the normal switch on/off. Whereas the digital display will remind you of
any fault so that it could be easy for the engineers to diagnose what’s the
fault in the boiler. Controlling and regulating hot water temperature will be
on your tips as you can manage the settings through your smart phones because
of smart and techy thermostats.
Efficient- the ecoTEC plus 838 combi
boiler is a ‘A’ rated brand with an ErP(Energy related Product) of 89.3%. With
its superb performance, it will reduce the amount of energy wasted and thus
reduces the carbon footprint. The outstanding performance will surely help you
in saving your energy bills.
New flame lit detection system – the burner is automatically
monitored to ensure the minimal combustion and noise and have a back-up so in
the fault, combustion boiler will get back to the previous options. This is all
done by the innovative new flame lit detection system.
Reliable – this boiler is reliable as it
comes with frost protection, keeping it protected from cold days. This boiler
has high level of technology that are made to keep a check within every 30
seconds to make sure that there is low combustion and eliminate the for the
users to check and maintain the carbon dioxide level as well.
Warranty – this Vaillant ecoTEC plus
boiler provides you 5 year standard warranty which can be extended up to 7
years if you install it frm Vaillant Advance installer.
Boiler height – 720mm
Boiler depth – 372mm
Boiler width – 440mm
Boiler weight – 38kg
Warranty – 5 years
Flow rate – 14.3l/min
Power output – 35kW
Fuel used – Natural Gas
The Vaillant ecoTEC 835 is an excellent choice if you are
searching for bigger properties. This range is highly efficient and reliable
ehich helps in reducing the carbon prints. Th ecoTEC plus boiler has been
awarded Quiet Mark status for low noise and output.
Whereas its astonishing design will surely make you purchase
it for your place.