I've got a Jenn Air stove with a downdraft fan vented to the outside. In
the winter, cold air seeps in from the outside (I do have a louver mounted
on the outside wall). Sometimes when it's really cold you can freeze a
small drop of water on the stovetop. I usually need to put a dishtowel over
the vent which helps a bit.
The Jenn Air website suggests installing something called a 'thermal break'
which is described as a non-metallic (so as not to conduct heat) piece in
the air duct as close as possible to the outside. No one at my local stores
has ever heard of this device.
Does anyone out there know what this looks like and possible where else I
could find one?
Thanks in advance!
A thermal break is probably just a piece of pvc in the run to stop the
transference of heat/cold. You probably need an new damper outside. The
damper on my exhaust fan does not work very well especially in windy
weather. I live in a pretty temperate climate so I am not going to do
anything about it.
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Found this on a search:
"Cold weather installations require an additional backdraft damper
installed to minimize backward cold airflow. In addition, a non-metallic
thermal break is needed to minimize conduction of cold airflow through
the ductwork. The damper should be in the cold air side of the thermal
break, and the break should be as close as possible to where the ducting
enters the heated portion of the house."
I read this several times. Lot of double talk...OK. Thermal = heat and
break = break. So break the heat. Simple!
I built my own thermal break for my Jenn-Air and didn't know to call it
that - I cut a piece of heavy cardboard and keep it wedged in (where the
big hole is, behind the woven metal filter.
In really, really cold weather, I wrap a piece of aluminum foil over the
top vent and fit it under the edges and re-insert the top vent piece.
Pull it out when you want to grill or use the fan.
May not be pretty but it works. The cardboard is not visible so unless
it is very cold, you don't need the aluminum foil part.
I have a real love/hate with the Jenn-Air. LOVE the ability to grill
Thanks for the reply. Sounds like you do the same with foil that I do with
a dish towel.
The only problem with the cardboard idea is that you can't use the exhaust
fan when the cardboard is blocking the exhaust duct. I found the same text
in my search but I interpreted that the 'additional backdraft damper' would
be a hinged affair of some sort which open and allow exhaust to exit the
house, but not allow cold air in.
You remove the cardboard when you are using the fan. The cardboard does
not show and keeps the cold air out when you are not using the fan. So
it works better than just covering the top vent.
If you find something that works better, please post.
P.S. I bought most of the replacement parts for the top, to hold and put
on when I sell this house. I have used Jenn-Air grill tops (in 4 other
houses) for over 30 years and this is the only one I've had that the top
pieces are of such poor quality. Only gas Jenn-Air I've ever had so that
might be the problem.
I've seen those on the outside wall, just like the stove exhaust damper but
I haven't ever seen an additional one that is inside the ductwork. The
inside of my dryer is cold in the winter but the dryer door seems to do a
good job of sealing it off from getting in the house.
Perhaps not all dampers are created equal. Mine have thin plastic louvers
which open and close with the air going out. I've also seen ones which have
more of a circular plastic flapper plus a rain-hood of some sort, I think
maybe I'll give one of those a try.
Here's a different one:
I had one of those for many years. It worked pretty good with the gas
dryer. I don't know what the air pressure of the stove vent is, so I
don't know whether it would provide enough to lift that shuttle inside
the vent. I had to move the vent outlet last year to make room for an
addition and I went with a different kind, or else I would still have it.
replying to Charles Spitzer, Linda wrote:
I have a jenn air flapper on the outside of my house with a screen back some
distance so small animals cannot get inside the crawl space. It has been
checked by the installer twice and said to be ok. I think cardboard or
insulation needs to be put where air comes in from the outside of this flapper
in back of. Maybe cardboard here.? I know a folded up piece of cloth does not
help- not warm.
On Friday, December 7, 2018 at 8:14:10 AM UTC-5, Linda wrote:
The exhaust fan is just there to take out smoke or odors when cooking
something on the cooktop that requires it. Only use the fan here
maybe 1% of the time. If you're running it when it;s not needed,
you're just pumping heated air from inside to the outdoor.
As I stated previously, I cut out a piece of
the flexible material that you use to line drawers and put that over
the vent opening in the cooktop. It's doesn't seal perfectly, but
it's effective enough to keep most of the cold air out.
replying to Linda, Linda wrote:
Sorry, above did not come out right. Space to write is too small. I was saying
cold weather makes my radiant smooth top large burner stop working. Installer
put a new part in but it still does this and Christmas is coming soon. Can’t
use my burner and oven is probably off with 13 degrees temperature outside.
This is a 3000. piece of junk. I will have to remove cardboard from outside
wall under the flap and then come inside and remove the 2” insulation board in
the middle section vent! But no burner!
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