INSTALLING AIR DUCTS
A well designed and installed ducting system will allow the
ERV to operate at its maximum efficiency.
Always try to keep duct runs as short and straight as
possible.
See Figures 6-9 for diagrams of various installations.
Outside Weatherhoods
The fixed covered hoods have a built-in bird screen with a
1/4" (6 mm) mesh to prevent foreign objects from entering
the ductwork.
Locating the Intake
Weatherhood
• Should be located upstream (if there are prevailing
winds) from the exhaust outlet
• At least 6' (2 m) from the exhaust weatherhood
• At least 6' (2 m) away from dryer vents and furnace
exhaust (medium or high efficiency furnaces)
• A minimum of at least 6' (2 m) from driveways, oil fill
pipes, gas meters, or garbage containers
• At least 18" (457 mm) above the ground,
or above the depth of expected snow accumulation
• At least 3' (1 m) from the corner of the building
• Do not locate in a garage, attic or crawl space
Locating the Exhaust
Weatherhood
• At least 6' (2 m) from the ventilation air intake
• At least 18" (457 mm) above ground or above the
depth of expected snow accumulation
• At least 3' (1 m) away from the corner of the building
• Not near a gas meter, electric meter or a walkway
where fog or ice could create a hazard
• Not into a garage, workshop or other unheated space
When installing the weatherhood, its outside perimeter
must be sealed with exterior caulking.
Installing the ducting from
the weatherhoods to the ERV
The inner and outer liners of the flexible insulated duct
must be clamped to the sleeve of the weatherhoods (as
close to the outside as possible) and the appropriate port
on the ERV. It is very important that the fresh air intake line
be given special attention to make sure it is well sealed. A
good bead of high quality caulking (preferably acoustical
sealant) will seal the inner flexible duct to both the ERV
port and the weatherhood prior to clamping.
To minimize air flow restriction, the flexible insulated duct
that connects the two outside weatherhoods to the ERV
should be stretched tightly and be as short as possible.
Twisting or folding the duct will severely restrict air flow. See
Figure 6 for the recommended connection of flexible insu-
lated ducts to the the outside weatherhoods and the ERV.
Ducting
To maximize airflow in the ductwork system, all ducts
should be kept short and have as few bends or elbows as
possible. Forty-five degree elbows are preferred to 90°
elbows. Use “Wye” (Y) fittings instead of "Tees" (T) whenev-
er possible.
All duct joints must be fastened with screws, rivets or duct
sealant and wrapped with a quality duct tape to prevent
leakage. We recommend aluminum foil duct tape.
Galvanized ducting from the ERV to the living areas
in the house is recommended whenever possible, though
flexible duct can be used in moderation if so desired.
To avoid possible noise transfer through the ductwork sys-
tem, a short length (approximately 12 " or 300 mm) of non-
metallic flexible insulated duct should be connected between
the ERV and the supply/ exhaust ductwork system.
The main supply and return lines connected to the ERV
must be the same diameter as the duct connections (or
larger for extensive duct runs). Branch lines to the individ-
ual rooms may be as small as 4 inches (100 mm), but 5
inch (125 mm) lines are preferred .
All ducts running through attics and unconditioned spaces
must be sealed and insulated to code.
HOOD
BIRD
SCREEN
BELT OF OUTSIDE WALL
THERMAL COLLAR
INSULATED FLEXIBLE
DUCTING
1/ Thermal Collar slides over galvanized
sleeve of Weatherhood.
2/ Fasten Thermal Collar to Belt.
3/ Slide the Insulated Flexible Ducting over
the Weatherhood’s galvanized sleeve and
fasten it to the Thermal Collar.
4/ Hood is hinged to allow for easy access
for cleaning of bird screen.
WEATHERHOOD INSTALLATION
TI 15
17
Figure 4
