PRODUCTS | WINDOWS
01
02
03
04
DO YOUR WINDOWS LEAK AIR?
CHECK WINDOW INSTALLATION WITH A BLOWER DOOR TEST
W
e all know how important it is to
choose the correct window. Yet
the options and combinations
seem endless; aluminium, timber, uPVC or
composite frames, double or single glazed,
coated or uncoated glass, climate zone
considerations, the U-value and the SHGC.
Once you have done all the hard work of
specifying the window, it’s now up to the
builder to install it correctly. Or do they?
When the house is finished, the windows
might look great, but something doesn’t
seem quite right. The home constantly feels
either too cold or too hot.
This is one of the most common reasons a
home owner asks for a blower door test on
their home. In addition to this, some home
owners are looking for ways to save energy
and want to identify ‘air leaks’ to improve
their heating/cooling system’s efficiency.
WHAT IS A BLOWER DOOR?
A blower door is a machine used to measure
the airtightness of buildings. It can also be
used to measure airflow between building
zones, to test ductwork airtightness and
to help physically locate air leakage in the
building structure. Whilst air tightness is not the answer to
all problems, it’s a start. Once a building
is designed and built tight, mechanical
ventilation may be required.
The CSIRO analysed the results of 129 new
homes tested for air tightness and more than
half of those tested returned poor results.
These houses scored over 15 air changes per
hour at 50 Pa (15 ACH at 50 Pa). There is an old saying in the blower door
industry, ‘Build tight. Ventilate right’.
For more information, visit
www.blowerdoorservices.com.au or call Peter on
0434 334 020.
The most common areas of air leakage are
around windows and doors, down lights,
extraction fans and floor-wall joints.
For perspective, a new home owner in
the United Kingdom will not be issued a
Certificate of Occupancy if the permeability
is greater than 10 m 3 /hr.m 2 , or approximately
10 ACH at 50 Pa. In Europe, this requirement
is less than 5 m 3 /hr.m 2 .
While buildings need to be airtight in a cold
climate, it is just as important in a warm
climate. In Florida, USA, which has a climate
similar to Brisbane, the maximum allowable
permeability for a new build is 7 ACH at
50 Pa.
01 Window architrave thermal image (left): The
blue zone shows cold air leaking through
the architrave and wall.
02 Window architrave thermal image (left): The
white zone shows warm air leaking into the
house due to early sun on the north facing
windows.
03 Door architrave thermal image (left): The
blue zone shows cold air leaking into the
house around the door architrave.
04 The door architrave hid a 20 mm gap
between the door frame and the stud wall.
WINDOWS MAGAZINE 41