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An extra-large heat exchanger (or two heat exchangers
in other cases) within the boiler is used to reclaim
the heat from some of the expelled hot gases. This
way the system maximises heat transfer from the
burner while recovering useful heat that would normally
be lost with the flue gases.
Traditional boilers have typical efficiency rating
of 70%. Efficiency rating for a boiler represents
the percentage of useable energy output compared
to the energy input. A high efficiency condensing
boiler will have efficiency rating of at least 86%.
An A rated boiler will have an efficiency rating
of over 90%, with a B rated boiler will have at
least 86% (and both rates will qualify for the ‘High
Efficiency” band).
According to the Government’s new building
regulations, all new boilers installed in England
and Wales from April 2005 must be of high efficiency.
High Efficiency boilers are up to 35% more efficient
than traditional boilers and will substantially
reduce the energy used for water heating in your
house hold.
The benefits of installing a high efficiency condensing
boiler are substantial and can reach £100-120
per year on your space heating and water heating
bills. In addition, a quality condensing boiler
will reduce your household’s CO2 emission
by approximately 800Kg per annum.
Estimating the Boiler Size
Calculating the size of the required boiler needs
to be done carefully, taking into account the size
and the layout of the property, the number of rooms
and bathrooms, the profile of hot water usage and
many other parameters.
Your plumber or heating engineer will be able to
calculate accurately what type and size of boiler
you actually need to install.
Limitations on where to fit a Combi Boiler
In general terms, you can position the boiler anywhere
in the house. However, there are some considerations
you need to take into account such as planning a
path for an outside access for the flue, as well
as meeting all relevant building regulations.
Efficiency Ratings
Boilers’ efficiency is rated according to
SEDBUK – Seasonal Efficiency of Domestic Boilers
in the UK. The scheme was developed by the government’s
Energy Efficiency Best Practice Programme (in conjunction
with the main boiler manufacturers), to create a
fair comparison of boilers efficiency and energy
performance. The scheme enables consumers and heating
engineers to choose an appliance according to its
efficiency and is in effect an energy labelling
system for the heating and boiler market.
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These percentages represent average efficiency
achieved for a typical home, based on standard
assumptions on annual usage, climate and controls.
Rating within bands “A” or “B”
qualifies a boiler to be called a ‘High
Efficiency’ boiler. |
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