Condensation
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 unheated 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 Input Ventilation
units (Dampbuster) along with our Passive Ventilation
Units (Mouldbuster) are a cost effective and guaranteed
way to control condensation and black spot mould
problems.
Positive Input Ventilation units (Drimaster-for
houses and Flatmaster for flats-amazingly)
Drimaster
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 damp proofing 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.
All DRIMASTER 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 £850.00.
(Interest free credit available).The benefits of
installing a Drimaster PIV unit are great and some of
the advantage are listed below:-
- First, it means that a significant proportion of
external pollutants are prevented from entering the
home.
- Secondly, the use of the otherwise unused heat
in the roof results in the ventilation unit
providing a significant net energy gain to the home.
- Thirdly, there is no better way to ventilate a
home than from the inside out via a single,
centrally located, supply air diffuser.
The installation of a low energy positive input
ventilation unit will ensure the air in your home is
completely replaced with better quality air around 20
times a day. This is the recommended rate to maintain
good air quality. The old air exits through the
thousands of air leakage points found in all homes.
Indeed, positive input ventilation will even help to
suppress unwanted infiltration (draughts).
The end result of installing a DRIMASTER PIV unit is
improved indoor air quality and an environment in which
condensation dampness cannot exist.
Flatmaster
The Flatmaster operates in a similar way to the
Drimaster but is designed for homes without lofts.
Input air is directed across the ceiling (usually in
your hallway). This uses a scientific principle called
the Coanda effect, which has the impact of mixing with
the wasted warmer air that has risen above head height
in your home. It therefore increases the efficiency of
your heating system. We can also supply and fix heat
exchange units if preferred.
The unit will cure and/or prevent the problems
associated with condensation dampness in your home,
providing a healthier living environment for all
occupants. The unit will prevent mould growth on walls,
ceilings, furniture, clothes and curtains. The unit also
eradicates the musty smells evident in homes with severe
condensation problems. (When using your air conditioning
in the summer, fresh air will circulate the house and
help to prevent dry throats and congestion).
The price for this unit supplied and fitted is £898.00
which includes all making good and localised
re-decorating.
Passive Ventilation Units
In some instances where cost is a concern and only
individual rooms require to be treated we can recommend
the ‘Passyfier Vent’ which has no running costs, has
minimal heat loss and is scientifically proven to reduce
condensation dampness.
The Passyfier combines a through-the-wall ‘warm’
telescopic sleeve with a slab of mineral wool inside,
which is impervious to the exodus of moisture vapour
whilst an internal louvered vent and an external cover
simultaneously preventing cold draughts.
A typical house may need for or five Passyfier units and
they operate by taking advantage of the differential
partial moisture vapour pressure that is normally higher
inside an occupied building than on the outside. This
pressure is completely independent of that in the air,
for example, a typically cold misty British winter’s day
may have an outside temperature of 5degC and humidity at
100% while the inside temperature is usually around
20degC. Keeping the inside relative humidity to 70%
generates a difference between inside and outside
moisture vapour pressure of 8 millibars which is ample
to alleviate condensation. All this is achieved with
little or no heat loss and the Passyfier will
significantly reduce condensation dampness, steamy
windows and unsightly, unhealthy mould growth.
The Passyfier operates continuously without noise 24
hours per day and can extract up to 2.3 litres (roughly
one and a quarter gallons- which is ten pints) of water
per day even at low pressures.
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