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Best practice for installing a vented range hood?

Mach70's picture

I have a vacation cottage in northern Michigan.  I'm planning to put on cedar siding in the spring so right now I'm thinking ahead to trim, light & outlet mounts, etc.  A vented range hood is planned.  I'd like to install an above-range microwave that vents to the outside.  The wall in question is the north-facing wall and since the cottage is on a lake it can get windy there.  Is there anything more energy conservative than cutting a big hole in the wall & pushing a sheetmetal collar through it?  I'm concerned for drafts, heat loss & an ice-cold microwave in the winter. 


I've installed a couple such microwaves in the past but both times the vent went up into the kitchen soffit so the long run made the leaky damper less of a concern.  This kitchen won't have a soffit so using the rear outlet & going right out the wall seems most logical.

Advice?

Here's your most energy conservative answer.......... (post #207502, reply #1 of 17)

Self venting.

Get the additional charcoal filter and vent it out to the interior.  The grease is caught by the  first filters, some of the aroma, by the charcoal filter.

Besides, what's better than waking up to the smell of bacon in the pan...............

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


Do you really like self venting? (post #207502, reply #14 of 17)

Hey Calvin, do you really like "self venting" hoods, or just in this case?   I like the idea of not exhausitng warm air to the outside, but I find that if you burn something the hood just circulates the smoke around the room.  The might pick-up grease, but do nothing for the smoke.  Yes, yes, yes, I know; when cooking you are not supposed to burn the food.  LOL

.

Personally. (post #207502, reply #15 of 17)

We have a vent in the micro-never use it.

period.

 

If we did-it has the charcoal filter that is supposed to remove the aroma (sort of).  The grease filters remove the grease-but they all do.

 

If we even used the vent, I might be better informed to answer.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


Down Draft? (post #207502, reply #16 of 17)

So do you have a down draft or no vent at all?

.

Do (post #207502, reply #17 of 17)

We might as well not have a vent.

But, there's the 300 cfm vent in the above the range micro.  It's in there that we have the motor turned to Self-Venting.  Coupled with the charcoal filter-we are set up to use the vent.............SELF.............

 

but,

 

 

we don't use it.

 

Broiling-all outdoors on the grill-summer/winter/rain/shine/nite/day................

Pasta boiling-mostly semi covered-and we're not italian.

soup-slow cookers.

 

Bacon-not often.

Deep fryer-never.

 

 

OK, was I not clear in my previous post?

 

Personally.

by
calvin in reply to DoRight [original] on Wed, 02/27/2013 - 14:21

We have a vent in the micro-never use it.

period.

 

If we did-it has the charcoal filter that is supposed to remove the aroma (sort of). The grease filters remove the grease-but they all do.

 

If we even used the vent, I might be better informed to answer.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


What's above? (post #207502, reply #2 of 17)

What's above?


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

The roof? (post #207502, reply #3 of 17)

but if the suggestion would be to go out the roof, I'd agree a better backflow damper (than the ones in a micro hood) could help-but

In Northern Michigan, there's some serious snow that very well could cover that vent an render it non operational. 

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


Make sure you buy a good, (post #207502, reply #4 of 17)

Make sure you buy a good, sealed damper for it that goes on the outside. Your situation isn't much different than many houses in America so it's done every day.

Florida Licensed Building Contractor, 40 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

I prefer to vent it outside, (post #207502, reply #5 of 17)

I prefer to vent it outside, even though it's inefficient.  I just don't want cold air coming IN and the damper included in every over-range microwave I've seen is junk.  1/4" gap around the flapper, and so lightweight a strong breeze will suck it open.

ok (post #207502, reply #6 of 17)

Then get a spring loaded damper (backdraft damper) that has gaskets around where the interlocking flappers seal and that's the best you get.  The fan will have no problem opening it.

Insulate the pipe-problem being, that damper and a rect. to round transition will exceed your wall thickness.  I am familiar with how good a job the round damper does, not at all sure how the rectangular one does-you might be able to find one, then put a cheap flapper boot on the wall.

Even the exterior mounted fans have a rather cheap gasketed damper on the cap-they do ok, but don't seal all that well..............better than a micro flapper.

I'll look for an online supplier of fans and hardware-might find something for you..............

Take a look here and give them a call-they seem knowledgable the couple times I've talked to them.

http://www.hvacquick.com/products/residential/Ventilation-Accessories/Discharge-Caps/wall-hoods-rectangular

Whether the seal on the ones pictured is any good-can't say.  Ask them.

Remember tho, you still are going to have one cold pc. of metal that's going through the wall and connecting up to the metal on your micro.  There's zero thermal break.  If it keeps air from coming back in, that's all you're going to get.

Here's a tip-on dryer single flappers that seal real bad and flop around on windy days-silicone some big fender washers to the flapper.  It takes more power to open it, but with a 5inch distance from your fan to the cap-shoot, you could silicone a crescent wrench on there and it would work real well.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


Do you think there would be (post #207502, reply #7 of 17)

Do you think there would be any real advantage in mounting the outside hood up higher on the wall and installing a "periscope"-shaped 3.25 x 10 duct in the wall?  With the extra offset I maybe could add a thermal break or make the duct out of rigid foam or ductboard.  (wall work is planned and I"m pretty sure the range is centered against a stud anyways)

Maybe I'm over-thinking this.  I haven't heard anyone complain about their vented hoods leaking or their microwave frosting up :)

Youmightbe....... (post #207502, reply #8 of 17)

overthinking.

Every jog, turn, narrowing of size, change of shape you add ............

gives you the downside of a bit more noise.

Admittedly, just having the motor right there is noise enough.

 

Add a couple of those weights to the flapper and if you can, get one with a decent door and weatherstrip.  You should be alright.

See if HVACQuick can send you a picture of that flapper................if it's the same vent cap you can get locally, look at the one in your area and make the decision.  I got an inline 6" round damper from them.  Good springs, good weatherstrip.  I was satisfied. 

I've installed the rect. cap direct through the wall and had to add a couple fender washers-which ended up making it seal well (not flop around in the wind and allow cool are back into the room).

Where in N.Mi?

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


where? (post #207502, reply #10 of 17)

calvin wrote:

Where in N.Mi?

Near Atlanta.

Atlanta? (post #207502, reply #12 of 17)

No kidding?

 

there's one in Georgia.

 

is that in the UP?

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


I would definitely not put (post #207502, reply #13 of 17)

I would definitely not put jogs in a kitchen vent. If you get grease buildup it would be all but impossible to clean.

A duct to the outside (post #207502, reply #9 of 17)

is by definition a hole is your building. Best thing you can do is to seal the duct tightly (foil tape, mastic, etc), seal the penetration is goes through (canned foam, caulk, etc) and use a quality wall or roof cap. I like Seiho caps for almost everything that goes through a wall, here's an example, you could ask them if this is OK for a range hood http://www.seiho.com/product/sfx/sfx.html of course you might have a rectangular outlet...

I ran my range hood out the roof due to location. The flapper seals pretty well. You can always add a little bit of weight to it if it doesn't (use one or more small magnets to weight the flapper).

Baffle Box (post #207502, reply #11 of 17)

You could also build a baffle at the outlet so it doesn't see as much of the direct wind.