What is a combi boiler?
high efficiency condensing combi or
combination boiler is an ingenious
space-saving idea, and an
increasingly popular choice in UK
homes. In fact, combis now account
for well over half of all the new
domestic potterton boilers installed
in Britain every year.
major difference between a combi and
any other type of
is that a
boiler eliminates the need
to store hot water -- so no hot
water cylinder in the airing
cupboard. It is both a
high-efficiency water heater and
central heating boiler, combined
(hence the name) within one compact
unit which usually sits in the
kitchen or utility room, or
sometimes in the airing cupboard.
The space savings result from the
fact there is no hot water storage
cylinder, cold water storage cistern
or other familiar components of a
regular (conventional) heating
further benefits of this are a
significant saving on hot water
costs, and the fact that hot water
is delivered through your taps or
shower at mains pressure. So you can
enjoy powerful showering* without
the need for a pump. Another combi
benefit is that it can generally
save you money on installation time
and costs -- no tanks in the roof
space means less pipe work and a
shorter installation time.
are not new, they have been around for many years
and users report very significant reductions in fuel
costs. This is possible, because the condensing type
of worcester bosch boiler has a much more effective 'heat exchanger'
allowing more heat to be removed from the flue
One of the most
significant effects of this is the 'pluming',
sometimes mistaken for 'steam' coming out of the
flue terminal. This effect is brought about by water
droplets held in suspension in the flue products and
although non-hazardous, it may be a nuisance if seen
constantly passing across windows. This pluming will
be evident for most of the time the
boiler is operating, so care is needed in
positioning the terminal.
boilers have a somewhat higher capital cost than
non-condensing boilers, for larger dwellings (with
three or more bedrooms) they usually prove to be
cost effective within several years.
condensing potterton gas boiler might have a seasonal
efficiency of around 88% compared to non-condensing
boiler of about 75%, and an older type boiler at
between 55% -60%.
are as easy to install as any non-condensing boiler,
but can only be fitted to 'fully pumped' systems.
During it's operation, condensate forms and,
although no more acidic than rain fall, a permanent
pipe must be run to a drain.
are available as a wall mounted or floor standing
Most wet central
heating systems use a boiler to heat a copper
cylinder in the airing cupboard to provide stored
domestic hot water. A combination boiler (usually
referred to as a 'combi' ) provides a means of
generating instant hot water for the taps from
within the unit and combines this with central
By using a 'combi'
neither a hot water cylinder, nor it's feed tank,
are required. Consequently, hot water running costs
will be reduced very slightly since there are no
standing losses from the cylinder or combination
boiler pipework. Although a continuous flow of hot
water is constantly available from a combination
boiler, the flow rate is not likely to be as good as
with a traditional storage cylinder, particularly in
In dwellings (often
larger type) where a number of draw-off points
(taps, showers etc) are likely to be used at the
same time manufacturers advice should be sought as
to the combi's suitability. Showers fitted to a
combination boiler must be a 'mains pressure' type.
combination potterton boiler is fed directly with mains cold
water, it is vital to establish that the minimum
water pressure, specified by the manufacturer, is
available otherwise the hot water performance will
are by far the most popular potterton boiler type, accounting
for over 50% of all new boiler sales within the UK.
(instantaneous) boiler is the most widely
used type of combination boiler and directly heats
incoming mains cold water to supply hot water to
taps, showers and other draw off points.
(instantaneous condensing) combination
boiler operates in principle as an 'instantaneous'
type but at somewhat higher efficiencies
heating radiators, radiator covers, towel radiators,
emitters' can come in all shapes, sizes and forms.
The most common
central heating radiator is the steel panel type
radiator and they are available in a very wide range
of sizes and styles intended to match as closely as
possible individual room needs.
are becoming increasingly popular, whilst the use of
cast iron radiators is also on the increase where
the intention is to blend with existing traditional
decoration. Towel radiators are most often used in
bathrooms and WC's where the towel radiator can be
used to store towels as well as heat the room
as a bathroom radiator. Designer radiators are more
money but designer radiators can make a design
statement and be a feature in a room. You may decide
to cover up a radiator with a radiator cover, this
may be because the radiator is old or unsightly.
Radiator covers come in many designs to suit your
room decor and most radiator covers are made from
mdf. Some radiator covers can be painted in your own
Radiators need to
be matched to the room size and also how the room
will be used to ensure the correct temperature can
be maintained. How the house is insulated, including
double glazing, can alter how efficient the
radiators are at warming a house.