COMMENT
Tackling trickle vents
Are trickle vents really fit for purpose? Jon Vanstone, chair of Certass
TA, suggests the industry should look at alternative methods of providing
ventilation to homes.
No-one can argue against the necessity
for background ventilation to be
delivered in the built environment.
But, the requirement to provide
this via trickle vents in windows is leading
to misconceptions in the level of ventilation
present in a property and causing issues around
acoustics and aesthetics for our industry.
Ventilating the home has never been more
important than now. Historically, our buildings
had ill-fitting doors and windows, open fireplaces
(or ventilated chimney breasts), ill-fitting loft
hatches providing many opportunities for internal
stale air replacement. However, over recent
decades we have been doing more and more
to improve the air-tightness of our buildings
by gasket sealing all openings and even springloading
and adding brushes to letterboxes.
The need for whole dwelling ventilation is
explained in Approved Document F (ADF),
emphasising its importance in the provision of
fresh air and removal of water vapour. Both of
these factors are huge contributors to the health
and wellbeing of occupants and also to the
wellness of the building by addressing the battle
against condensation.
Unfortunately, the requirements to install
trickle vents when replacing windows fitted
with them or when the room is not ventilated
adequately, leads to a number of issues because
the drive for their use seems to be more from the
cheap means of provision as opposed to their
effectiveness.
With this is mind, Certass is starting a new
campaign to lobby government on amending
the regulations surrounding the use of trickle
ventilators in windows. It has been a controversial
issue over a number of years due to the majority
of occupants, consumers, installers and
manufacturers being not in favour of their usage.
Providing trickle ventilation within a
fenestration product, simply because it is cheap
and convenient, does not make it a suitable
solution for whole house ventilation. Especially
when that solution is rendered ineffective due to
human non-acceptance and intervention.
We rely on manual operation by consumers,
who just as easily could open or close the
window itself and without an easy way to enable
consumers to understand the impact of bad
ventilation, the situation is getting more urgent
especially when combined with the increasing
number of overheating deaths in the UK.
On top of this, consumers consistently
complain about the sound issues caused by the
vents, especially when they live in busy areas,
often leading them to insert silicone within the
opening. And the use of curtains and/or blinds
often hide the ventilators and any effectiveness
throughout the year to varying degrees.
As an industry, we all understand these
issues – but our communication to government
is critical. We need to make it absolutely clear
that the high levels of thermal insulation in a
well-engineered and well-manufactured window
is ruined by the provision of an unrestricted
passage of external air either adjacent to it or
through it.
Government’s own research in ‘’“”/‘’“6
into ventilation and indoor air quality in 8’ new
homes, found that less than —% of the naturally
ventilated homes met the guidance in ADF with
respect both to trickle ventilator provision and
intermittent extract fan air flow rates.
Further improvements in thermal performance
of windows will enhance the detrimental effect
of trickle ventilators on the overall performance
of the product. And as air tightness in buildings
increase, so will the need for a more effective
means of whole dwelling ventilation.
Whether Government will review the position
is debatable, but when no stakeholder group
is happy with the outcome, surely it is time to
think again. Even the World Health Organisation
(WHO) is clearly expressing its negative view
on standards of natural ventilation for indoor
air quality, dampness and mould for a variety of
reasons.
In a perfect world, consumers would want a
well-insulated home with no draughts, where you
can replace stale, moist, low quality air with fresh
September www.ggpmag.com
“With this is mind, Certass is starting a new
campaign to lobby government on amending
the regulations surrounding the use of trickle
ventilators in windows”
air from outside without having to turn on the
heating to warm it up.
Government moved in the right direction
with some of the commentary under the Green
Homes Grant concerning heating the home, but
maybe it is time that the regulation is focussed
more on what can be achieved rather than
halfway steps that are more about cost than
effectiveness.
It is time to look again and consider
alternatives to trickle vents, such as a drive
toward whole house passive stack ventilation
systems. Perhaps then our industry can stop
punching holes in good, high-performance
products and ruining the thermal and acoustic
performance, for consumers who resent the
requirement to do so.
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