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WHAT IS CONDENSATION?
Condensation in a building usually occurs when warm air comes into contact with a cold
surface. The air is cooled below its saturation point causing its excess water vapour to
change into liquid water. The condensed water usually appears as water droplets or water
film on non-absorbent surfaces such as windows or tiles. This form of condensation is
described as surface condensation.
CONDITIONS FOR CONDENSATION
Condensation in dwelling houses is mainly a winter problem particularly where warm moist
air is generated in living areas and then penetrated to colder parts of the building.
Water vapour is produced in relatively large quantities from a large number of activities.
Condensation will also occur under suspended timber floors where the temperature of humid
air in the floor space is lowered by cold air moving in through ventilators and water is
then condensed on the underside of the timber floor, this will often induce timber decay
of the wooden floor.
THE CAUSES OF CONDENSATION
In dwelling houses condensation is related to modern living standards, economic pressure
and changing building design. The main cause of condensation is naturally the generation
of moist warm air by domestic activities. Moist air can come from cooking, bathing,
washing and drying clothes as well as paraffin heaters and flueless gas heaters - up to 17
litres of water can be produced daily in some homes! In certain areas such as bathrooms
and kitchens the moist, warm air can spread to cooler parts of the house to condense on
cold surfaces.
The effect of moisture generation is further aggravated by the way houses are ventilated -
it is theoretically possible to avoid condensation by adequate ventilation. Up to about
the late 1960s there was natural ventilation in many homes because of the lack of
double-glazing, poorly fitting windows and doors, open fireplaces. Present attitudes have
eliminated natural ventilation by the use of double-glazing, draught excluders, fitted
carpets (preventing air movement up through suspended wooden floor boards) and the removal
of open fireplaces with the introduction of central heating systems. To put it simply
buildings have being effectively sealed and provided ideal conditions for condensation to
occur.
Many houses remain unoccupied and un heated throughout the greater part of the day
allowing the fabric of the building to cool down, The moisture producing activities are
then concentrated into a relatively short period. This sudden increase in warm air can
produce condensation as the air comes into contact with the relatively cold structure
which is still warming up. Economic pressure - dramatic increase in fuel prices force many
occupiers to under use heating systems not heat unused rooms and seal all draughts and
reduce ventilation as described previously.
MOULD GROWTH
Mould growth will appear on any damp surfaces such as plaster, wall-paper and timber and
is associated with condensation problems in many buildings. It is unacceptable because of
appearance (unsightly growths of various colours - greens, yellows, pinks, black, grey or
white).
The main requirement for the development and growth of moulds is a source of moisture
although food, oxygen and a suitable temperature are also important. It is available water
which is critical to mould development. Moulds can be regarded as high hydrophilic fungi
(tolerating high water availability) although individual species have their own optimum
requirements for moisture. In most situations where surface condensation occurs and the
relative humidity of the internal atmosphere exceed 70% mould growth will be established.
There have been approximately 100 species of fungi detected in dwelling houses. The
species most commonly encountered were penicillium, cladosporium, rhizopus, and mucor.
CONCLUSION
Condensation is an increasingly serious problem in dwelling houses and offices.
It affects over 50% of buildings in the UK. Accompanying condensation there is an increase
in the presence of mould growth and many of the household pollutants. Positive Pressure
ventilation units along with complementary trickle ventilation are a cost effective way
(guaranteed) to control condensation and black spot mould problems.
ICS Ltd. have a full range of products to assist in condensation control.
All NuAire drymaster low energy input ventilation units are supplied and fitted with a
60 day, no quibble, money back guarantee and also comes with a 5 years parts & labour
warranty. An average sized 3/4 bedroom property, without extension, can be fully
installed, including all electrical connections for a flat fee of £698.00
ex vat.
(Interest free credit available).
The DRIMASTER provides
whole home ventilation using the Positive Input Ventilation principle. This form of
ventilation is becoming increasingly recognised as the “best value” approach to
ventilating a home.
Essentially, the concept is to introduce air to the home at a continuous low rate,
encouraging movement of air from inside to outside. A single unit situated in the loft
space will normally be sufficient to continuously dilute, displace and replace the old
contaminated air in the home with drier, tempered (by utilising otherwise unused heat in
the loft space) and filtered air. The result is a significant contribution towards
providing a healthy, condensation dampness free, energy efficient home.
With only one electrical connection and no trickle vents normally required, the
installation costs for this type of system are generally less than for a conventional set
of extract fans with trickle vents – and the entire home benefits from the
ventilation provided.
Good quality loft mounted units normally incorporate a heat recovery function to introduce
more heat into the home when the loft is warm during the winter months. Heat recovery
functions are normally either “Fixed Temperature Heat Recovery” which adjust the
flow rate of the unit to suit the loft temperature; or “Intelligent Heat
Recovery” which adjusts the flow rate to suit the loft temperature and the way the
home is heated. The latter type is particularly good in terms of energy efficiency.
These systems are highly effective but do require proper application and installation for
optimum performance.
Units incorporating low watt motor technology (Low Energy Positive Input Ventilation Units)
can provide a significant net energy gain to the home. These units are therefore very
energy efficient, even when compared to natural ventilation systems such as Passive Stack
Ventilation. |
NuAire Home Ventilation Ltd is the world’s
leading supplier of
Positive Input Ventilation Systems. |
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