We have an over the range microwave with built in exhaust that vents
outside through the attic. It is noisy as heck and I want to quiet
it. Seems like most of the noise is coming from the front grill where
the fan would exhaust back into the room if I did not have the outside
vent. Some noise is also coming from the cabinets directly above the
microwave as the rectangular metal duct goes directly up through it
and into the ceiling.

I have access to some 1" thick very dense fiberglass insulation used
in the marine industry for thermal insulation. I am thinking of
gluing this onto the outside edges of the metal duct as well and
stuffing it inside the space in the microwave behind the grill. It
won't cost anything to try, but was wondering if there is anything
better that is readily available at the local home depot.

On Tue, 23 Oct 2007 11:58:33 -0700, wrote:

We have an over the range microwave with built in exhaust that vents
outside through the attic. It is noisy as heck and I want to quiet
it. Seems like most of the noise is coming from the front grill where
the fan would exhaust back into the room if I did not have the outside
vent. Some noise is also coming from the cabinets directly above the
microwave as the rectangular metal duct goes directly up through it
and into the ceiling.

I have access to some 1" thick very dense fiberglass insulation used
in the marine industry for thermal insulation. I am thinking of
gluing this onto the outside edges of the metal duct as well and
stuffing it inside the space in the microwave behind the grill. It
won't cost anything to try, but was wondering if there is anything
better that is readily available at the local home depot.


I used to have an over-the-range microwave and the fan did not move
much air. After 15 years of use I was glad the microwave died. I
replaced it with a model that has 5 speeds and you can program it to
run the fan for a selected number of minutes and shut off. If I want
a quiet fan I set it to "1." If I want to quickly vent I set it to
"5." It has a fan that is 3X more powerful. Whatever you use to
insulate, use something that is non-flammable.

wrote in message
oups.com...
We have an over the range microwave with built in exhaust that vents
outside through the attic. It is noisy as heck and I want to quiet
it. Seems like most of the noise is coming from the front grill where
the fan would exhaust back into the room if I did not have the outside
vent. Some noise is also coming from the cabinets directly above the
microwave as the rectangular metal duct goes directly up through it
and into the ceiling.

I have access to some 1" thick very dense fiberglass insulation used
in the marine industry for thermal insulation. I am thinking of
gluing this onto the outside edges of the metal duct as well and
stuffing it inside the space in the microwave behind the grill. It
won't cost anything to try, but was wondering if there is anything
better that is readily available at the local home depot.

The noise is probably a function of that brand of fan. Some are
quieter than others and you just have to listen to different models or,
more doeable, do some online research. If there isn't and money
for a change out then I would use a little of that foam to make some
stand-offs to get the fan away from the cabinets. I would put a
2" x 2" piece under each corner at the very least. That should
eliminate your cabinet vibration. Best of luck to you!

C & E wrote:
wrote in message
oups.com...
We have an over the range microwave with built in exhaust that vents
outside through the attic. It is noisy as heck and I want to quiet
it. Seems like most of the noise is coming from the front grill where
the fan would exhaust back into the room if I did not have the outside
vent. Some noise is also coming from the cabinets directly above the
microwave as the rectangular metal duct goes directly up through it
and into the ceiling.

I have access to some 1" thick very dense fiberglass insulation used
in the marine industry for thermal insulation. I am thinking of
gluing this onto the outside edges of the metal duct as well and
stuffing it inside the space in the microwave behind the grill. It
won't cost anything to try, but was wondering if there is anything
better that is readily available at the local home depot.

The noise is probably a function of that brand of fan. Some are
quieter than others and you just have to listen to different models or,
more doeable, do some online research. If there isn't and money
for a change out then I would use a little of that foam to make some
stand-offs to get the fan away from the cabinets. I would put a
2" x 2" piece under each corner at the very least. That should
eliminate your cabinet vibration. Best of luck to you!

I had a range hood above the upper oven
of a 2 oven range that was very
noisy. Bad thing #2 is that it was a
recirculation type. I gutted it, fan
and filter, left the grease filter
screen, and added an on-roof fan.
After cutting a hole in the top of the
hood and connecting it to the
fan unit, all was pretty quiet. I later
remodeled, replacing the double
oven with a cook top and a new hood. I
connected it to the same
fan.

wrote in message
oups.com...
We have an over the range microwave with built in exhaust that vents
outside through the attic. It is noisy as heck and I want to quiet
it. Seems like most of the noise is coming from the front grill where
the fan would exhaust back into the room if I did not have the outside
vent. Some noise is also coming from the cabinets directly above the
microwave as the rectangular metal duct goes directly up through it
and into the ceiling.

I have access to some 1" thick very dense fiberglass insulation used
in the marine industry for thermal insulation. I am thinking of
gluing this onto the outside edges of the metal duct as well and
stuffing it inside the space in the microwave behind the grill. It
won't cost anything to try, but was wondering if there is anything
better that is readily available at the local home depot.


I'd cover the insulation with aluminum duct tape to seal the edges and keep it
from absorbing grease and becoming a fire hazard.

Bob

On Oct 23, 10:37 pm, "Bob F" wrote:
wrote in message

oups.com...

We have an over the range microwave with built in exhaust that vents
outside through the attic. It is noisy as heck and I want to quiet
it. Seems like most of the noise is coming from the front grill where
the fan would exhaust back into the room if I did not have the outside
vent. Some noise is also coming from the cabinets directly above the
microwave as the rectangular metal duct goes directly up through it
and into the ceiling.

I have access to some 1" thick very dense fiberglass insulation used
in the marine industry for thermal insulation. I am thinking of
gluing this onto the outside edges of the metal duct as well and
stuffing it inside the space in the microwave behind the grill. It
won't cost anything to try, but was wondering if there is anything
better that is readily available at the localhomedepot.

I'd cover the insulation with aluminum duct tape to seal the edges and keep it
from absorbing grease and becoming a fire hazard.

Bob


The amount of noise from the fan is measured in SONE - a 1.5 sone is
very quiet - a 7 sone microwave (most GE over-the-range microwaves) is
very loud. The noise comes from the style of fan blade, it's speed and
type of motor. A mocrowave fan 'may' have a hard time over coming the
static pressure of trying to push air up a long duct to the roof - esp
if the duct is the cooragated stuff or has any 90º angles. Go to
Lowe's and go to the plumbing section and look for bathroom exhause
fans - there should be a Broan (sp) display with three fans - from
loud to quiet. This will give an example of sone ratings. Maybe remove
the fan from the microwave and install an in-line quiet fan in the
duct somewhere in the attic area with a switch next to the microwave.
The fan being in the attic will move any fan noise from the kitchen to
the attic. Keep the existing grease filter in the microwave though.

Probably very little use to ask a sales person which microwave has the
most quiet fan as they usually say something like "the more expensive
the unit, the quieter it will be".