the animation you're about to see is based on a new home built to the most
stringent levels of air tightness and typical to those in the most
energy-efficient new homes the scientific computational fluid dynamics
CFD research was carried out by the University of Nottingham school for the
built environment as a new home becomes occupied the central heating is used and
the heat from radiators underfloor heating and other electrical sources
starts to rise and accumulate at the highest point in the dwelling at the
same time each occupant within the home will create around four pints of
moisture per day or up to 30 pints of water vapor each week this humidity
triggers the growth in dust mite populations and mold spores which mix
with carbon dioxide NOx gases and VOCs found in household cleaning products and
aerosols at the same time the oxygen levels in the homes start to deplete if
you could see the heat distribution along with all of the airborne gases and
contaminants in a poorly ventilated home then it would probably look something
like this we call this a viral soup the simulation
conditions in the property are taken at the worst possible case scenario where
indoor relative humidity is at 100% and outdoor relative humidity is also 100%
the roof tiles on a house often act as solar collectors and will radiate heat
into the loft space according to a recent energy-saving trust report the
good practice guide the average solar gain in a loft space throughout the
heating season is at least three degrees resulting in over five hundred and fifty
kilowatts of free energy the unit is switched on and the fresh filtered air
enters a home through the centrally-located ceiling mounted
diffuser the air is introduced along the underside of the ceiling and begins to
mix with the warmth contaminated air looking at the scale the CFD model shows
that after only one hour the humidity within the dwelling is showing yellow
which means the humidity has fallen to around 80% after two hours the air has
already fallen below 70% and the heat at high level has been totally
redistributed around the property saving energy
after three hours the dilution and displacement process is well underway
the quality of the air is starting to improve as a fresh filtered air begins
to dilute displace and replace the airborne contaminants
after six hours the relative humidity is at 50% and is now stable the air in the
property is clean and fresh the warm air that is normally lost at ceiling level
is been redistributed making the property much more energy-efficient
another strategy is known as multiple input ventilation as you can see from
this animation the loft unit is picking up free energy from the loft space
filtering the air and delivering it into the property through multiple ceiling
diffusers the advantage of using multiple inputs is that you can target
certain areas of the home where there may be a condensation or mold problem or
perhaps there may be a person suffering from hay fever or asthma when the loft
temperature exceeds 25 degrees the unit automatically detects this and activates
a damper that switches the air supply from inside the loft space to the cooler
air from outside the property the result is all year round whole house
ventilation fresh filtered air been introduced into the property in the most
energy efficient way possible for the past two decades enviro vent have
installed over 200,000 mechanical input ventilation systems the majority are
still working effectively and have cost the clients nothing in maintenance
mechanical supply ventilation is the most energy efficient cost effective
ventilation strategy that exists the cfd animation by Nottingham
University proofs scientifically why mechanical input ventilation is so
effective in both airtight and existing homes