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By running this fan through the night, homeowners can extract the maximum possible amount of heat from their
home’s structure and contents. This essentially “pre-cools” the home ahead of the rise in temperature the next
day, which reduces or can even eliminate the need for air conditioning. This VentCool Whole House Fan has
been designed specifi cally for quiet and effi cient operation. As such, we strongly recommend homeowners run
this fan through the night to reduce their energy expense.
With the above theory of operation in mind, adhere to the following guidelines when choosing a location for
this fan:
• Locate this fan in a central location, away from windows that will be opened during its operation. Installing
this fan centrally promotes an even replacement of air throughout the home, and the longer the path of air
travels from an open window to the fan, the greater the cooling effect.
• The damper provided with this fan can only be installed in a horizontal orientation, thereby requiring the
unit to be installed in the ceiling.
• Locate this fan at the highest point possible. This exploits natural convection and helps the fan exhaust the
hottest indoor air from the home.
• Typically, the ideal location for this fan in a two-story home is in the open area at the top of the stairs.
• Avoid locating this fan in a narrow space or over hard fl ooring as sound refl ecting off of hard surfaces can
amplify its perceived noise.
• Even though this fan is extremely quiet, we specifi cally recommend against installing it in a bedroom
as humans’ perception of noise is far greater when the surrounding environment is quiet (such as within a
bedroom at night).
• Within the attic, locating the fan near an electrical outlet or power supply can minimize the need for
additional electrical work.
The fi
rst step in installing this fan is to build a simple
“box” between the framing in the ceiling and to create an
opening into the attic. The fan’s backdraft damper has been
designed to fi t within a 14½” x 22½” ceiling opening, for VentCool 2.4
(See Figure 1A) and 22½” x 26½” ceiling opening, for VentCool 3.4 &
4.9 (See Figure 1B). Most modern homes have been constructed with
either 24” or 16” on-center (O.C.) spaced joists or studs. This
step varies slightly depending on whether the home’s framing
is either 24” or 16” O.C.
For 24” O.C. Framing:
Using appropriately sized lumber (e.g. 2”x4”, 2”x6”, etc.), install two
22½” long cross pieces between the existing framing, creating
a box with interior dimensions of 22½” x 26½”. Figure 1B at right
shows the framing and cross pieces as they should be installed.
For 16” O.C. Framing:
For VentCool 2.4 Gravity Damper, using appropriately sized lumber
(e.g. 2”x4”, 2”x6”, etc.), install two 14½” long cross pieces 26½”
apart as shown in Figure 2A.
For VentCool 3.4 & 4.9 Gravity Damper, using appropriately sized
lumber (e.g. 2”x4”, 2”x6”, etc.), install four 14½” long and one 26½”
long cross pieces between the existing framing, as shown in
Figure 2B to create 22½” x 26½” opening for VentCool 3.4 & 4.9
Gravity Damper.
Next, use lumber to construct a second frame with interior dimensions
of 14½” x 22½” for VC 2.4 or 22½” x 26½” for VC 3.4 and 4.9. Figure
2C shows a second 22½” x 26½” frame. Mount this new frame on top
of the frame created within the joists.
INSTALLATION: FRAMING
FIGURE 1B:
Box opening for VentCool 3.4 & 4.9
FIGURE 1A:
Box opening for VentCool 2.4
P/N 780100500 05/19 Rev B
