Bruce W. Maki,
This article describes how we installed a Panasonic WhisperLite
exhaust fan and light unit. Installing other fans is a similar
procedure. The fan, shown above, is a large metal box that mounts
between the ceiling joists. The light fixture, on the right, holds
two 13 watt fluorescent bulbs. The entire assembly is concealed by
the cover, lower left, which is held in place by two spring clips.
|The location for the fan.
This installation may be a little different than others,
because we installed the drywall before mounting the fan.
There is an attic above this room with plenty of space for
Why Install The Drywall First?
One task we wanted to avoid was having to cut a big hole in the
ceiling drywall, which would have required us to hold the 8' panel
in place and pound on the wallboard to make the metal fan housing
leave its mark on the sheet (the standard method for marking drywall
when a router or Rotozip tool is not available for cutting holes).
Having plenty of room in the attic, we just installed our drywall
with no holes in the ceiling.
||I used a stud finder to locate the ceiling
|I drove in a long screw in between two
ceiling joists, at a point that was centered in the room. When I
go up in the attic I will be able to find this screw easily.
||The attic above. The power supply cables had
already been brought into the attic, when the rough electrical
work was done.
||The front section of the fan unit slides off, so
just this section can be mounted in the ceiling, and the wiring
can be installed, before wallboard installation.
|Two thumb screws hold the black-painted fan box
to the front section. Note the two electrical connectors, one
for the fan, and one for the light.
The One Small Drawback:
There was only on small drawback to our method of installing the
drywall first. Panasonic intends for their fan to be mounted to the
side of a ceiling joist, so the flange on the black metal box gets
nailed to the underside of the joist.
For me to install the fan this way (which I could have done), I
would have had to cut away a little sliver of drywall along the
bottom of one ceiling joist. That would certainly be possible,
but it would take too long, and then the old wooden lath
(this room used to have plaster) would also have to be cut away. To
me, that just looked like a pain in the hind end. By simply
mounting the fan to a board, and then mounting the board to the
joist, all this hassle would be averted.
||I nailed the fan housing to a scrap of 2x6,
about 2 feet long.
|And I also attached the front section to the
||An easy thing to overlook:
I installed a 3/8"cable clamp on the electrical connection
box. It's easier to do these chores on the workbench rather
than in the attic.
Up in the attic, I used a small dust pan to excavate the
cellulose insulation and find the screw I drove at the beginning. I
also cleaned the area off with a broom, so I could see the layout
||I laid out the hole with a small rafter square
and a marker. The screw is visible near the top left of the
|I drilled a 1/2" hole at each corner, for my saw
||I made a few cuts with the reciprocating saw.
|I put a bucket beneath the hole to catch the
piece when it fell.
Before mounting the fan in place, I had to make the electrical
connections. Like most fans, this product is designed for new
construction, where the wiring is done before the drywall is
installed. The presence of the wood lath on the ceiling would have
added another aggravation to this process, had I done this the
There is another minor difference in my approach. Most
electricians would use 3-conductor wire to connect a fan/light
combination unit. Three conductor wire has two hot wires and one
neutral (plus the ground). One hot wire leads from the light switch
to the light, the other hot wire leads from the fan switch to the
fan, and the neutral returns the current to complete the circuit.
The homeowner had a couple of rolls of 2-conductor cable, and
with no other foreseeable need for 3-conductor cable, we decided to
simply run two lengths of 2-conductor cable. The only
difference is the presence of an extra ground and neutral.
||The ground wires were all tied together.
|The neutral and hot wires were connected, and
the wires were carefully tucked into the connection box.
||The cover was secured with a screw.
I went back downstairs to make sure that the fan was centered in
Now the fan and it's mounting board were attached to the ceiling
||I used 3" deck screws. I figured that nails
might cause cracks in my recent drywall job.
|There is a metal "out-rigger" bracket that helps
secure the other side to the next joist. I drove in two screws
Note: Because the mounting board I used reduced the width
between the joists, I had to shorten the "out-rigger" by cutting an
inch off with a reciprocating saw.
This fan used 4" diameter exhaust duct, which is commonly
available. Flexible duct is not recommended because its irregular
surface creates too much resistance to air flow, and reduces the
||First I connected a 90 degree elbow to a 5 foot
piece of duct. This was slipped over the exhaust port of the
fan. (The four metal tabs on the fan body had to be bent out
slightly to make a snug fit.
|The connection was taped.
Duct tape is no good! As much as we advocate duct tape,
ironically it is not recommended for holding ducts together. Plain
duct tape will probably turn brittle and fall off within a year.
Metal foil tape used above is much better, and definitely worth
the higher price.
||I caulked the gap between the fan and the
drywall, so the fan would not suck the particles of cellulose
insulation (and dirt) from the attic.
|The light was installed with 4 screws, and the
wire plugged in.
||The cover is installed by squeezing each metal
V-spring and inserting them into their respective clips.
Squeezing these springs is easier said than done.
|The finished installation.
The unit installed here is a
Whisperlite FV-08VQ2, which pumps about 90 cubic feet per minute (CFM)
of air. We also installed the slightly smaller FV-07VQL2 fan/light
(70 CFM) in another bathroom.
These fans are promoted as being extremely quiet, and they are.
Quite frankly, I have never heard a fan as quiet as these.
There are several measuring scales for sound and noise. One scale
uses a measurement called a Sone. This scale is exponential, like
the Richter scale for earthquakes. (I think some cheaper fans
probably register on the Richter scale.) When you go up one number
on the sone scale, the noise is ten times greater. Most of the fans
sold at discount home centers run around 2.0 to 3.5 sones.
The FV-08VQL2 installed here is rated at 0.9 sones, and the
smaller fan is rated at 0.5 sones. We are not talking about a few
percent quieter, we're talking about an order of magnitude
Let me put it another way: I'm a very light sleeper. I
cannot sleep with ANY noise in the background. I can't sleep with a
window air conditioner running in the next room, and I can't even
sleep with a computer running in my room. But the smaller fan we
installed is located about 10 feet from my bed, and I can sleep with
that fan running, no problem at all. Frankly, it's so quiet I've
wondered if it was even working. Before I finished the ductwork I
checked the air flow several times to be sure. It pushes a lot of
But, this peace and quiet comes at a price. At our local
supplier, the FV-08VQ2L sells for $187 and the FV-07VQ2L costs $174.
We thought the fans were well worth the higher price. We were only
able to find these fans at electrical supply outlets, the places
where contractors buy their lighting and electrical supplies.
These units are very energy efficient. The FV-08 fan motor
draws only 17 watts of power, and the FV-07 draws 15 watts. Each
unit uses a pair of 13 watt fluorescent bulbs (and the bulbs were
included), making them significant energy-saving devices. Since
installing these fans I've read a couple of articles about some
changes to residential building codes, changes that require more
ventilation. One solution that has been mentioned is the idea of
installing one of these Panasonic super-quiet fans and wiring it so
it runs all the time. Considering how efficient these fans are, that
sounds like a good way to obtain the desired ventilation without
racking up huge electric bills.
Having worked in the product design and engineering field, I was
extremely impressed with the quality of these fans. Panasonic uses
heavy gauge steel throughout. The plastic parts are precise and
heavy. Panasonic has put a great deal of attention to detail. Even
their packaging was remarkable (I know... the engineer in me really
shows up at times). The only negative thing I can say about these
products is their high price, but as often happens with building
materials, you get what you pay for.
Installing An Exhaust Duct
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- Cordless Drill/Driver
- Reciprocating Saw
- Small Rafter Square
- Basic Carpentry Tools
- Small Dust Pan & Broom
- Fan/Light Unit
- 4" Aluminum Duct, Elbows
- Metal Foil Duct Tape
- Roofing Nails, 1¼"