Range hood question

[Sasha]

I am remodeling my kitchen and I am going to install Broan custom RMPE range hood with exterior blower. The blower will be mounted on outside wall and will be connected to the hood insert with 8" elbow and 8" X

10" reducer duct following manufacturer's specifications. It means there will be 10" hole in the kitchen outside wall which will suck a lot of cold air at winter and hot air at summer. It will seriously compromise insulation of my house. Unfortunately, I do not know how to resolve this issue. Ideally, I would prefer to have some sort of air tired shutter that would close this duct when I am not cooking. I wonder what other people do who have range hood vented outside.

[Relz]

Isn't the purpose of a ducted range hood to suck the air from inside the kitchen and move it to the outside of the house? I don't know why air from the outside should be getting inside your house at all.

Please explain.

Relz

[Joseph Meehan]

That is the idea of a range hood blower. I don't think they work very well if they don't. Of course you could just not hook up the wires. :-)

There should be a damper that keeps outside air from coming in so it will only exchange air when the fan is running or for some reason your home is pressurized.

[longshot]

gravity louvers that only open when the fan is on.

[TURTLE]

This is Turtle.

you need to have make up air added to the hood and you will only pull out about

10% of the air pulled from the house. all commecial ketchens have these make up air type range hoods and could not afford the cooling cost without the make up air system to not pull all the air out.

There was a local chicken fring place here in town that did not use the by-pass air system on the range hoods and it took 25 tons of cooling to cool the building. He went to range hood by-pass air on his hoods and he only need 10 tons to cool the building now.

If You have possitive pressure on your home and then turn on a full pull range hood with no by-pass air on it. It is going to cost you big time on cooling when you run the range hood with no by-pass in hot weather. Now most home are set up this away and nobody cares to have by-pass air systems. Now All Commercial kitchens have by-pass air systems on their range hoods and do not want to pay big time on cooling or heating cost.

TURTLE

[Eric Tonks]

I am just installing the very same Broan range hood insert and have a Broan exterior fan on my roof. Both the fan and the insert have dampers which close when the fan is not in use to stop backdrafts. There will always be a little leakage but you do need some air exchange. Remember to insulate the pipe between the fan and the hood to reduce condensation if you are in an area that has real winters.

For your installation, I would reduce from the 10" fan to the 8" duct as close to the fan as possible, possibly with a 10" cap, with an 8" stub fitted into it. This would require you to cut the 8" hole in the cap and do some sheet metal work to fit the stub into it. This would allow the inside of the wall to only need an 8" hole. A transition fitting would be too long to accomplish this.

[Phil Scott]

custom RMPE

on outside

and 8" X

means

will suck a

seriously

The fan unit probably comes with a built in back draft damper that will open only when the blower is on. thats almost standard. Your kit probably includes that feature.

if not you can order it as an add on. not expensive.

Phil Scott

Unfortunately, I do not know how to

sort of air

cooking. I

outside.

>

[indago]

050504 0848 - Sasha posted:

Change your cooking habits and you won't need a range hood...

[CWatters]

Not exactly this but same idea..

[Eric Tonks]

What are you proposing --- eat everything cold. Boiling produces humidity, heat and odors that can travel through the house. Frying produces, grease, heat and odors that again travel through the house. A gas range produces byproducts of combustion that some people are sensitive to. If one is cooking a moderate to large meal, exhausting the humidity, heat (in Summer), odors and other fumes and vapors is a good idea along with allowances for make up air, but should only be run during the cooking and not left operating, as it will cause a larger load on heating or cooling or negative air pressure in the house.