Oct 26, 2013, 08:27 AMMary A
Retrofit Range Hood
We have a horrible recirculating range hood that we want to replace with an external venting hood. The kitchen is on the first floor of our two story home. How do we install the vent? We also have a covered porch. Can we vent through the porch roof? Or does that invite critter and grease issues?
Oct 26, 2013, 09:18 AMJaybee
Now you know why you have a recirculating hood. Sometimes it is just not possible to find a vent path.
First off, most hoods can be set to be either recirculating or venting - usually by rotating the fan to line up with the vent path. So if you can find a way to vent it, you can probably do so with the same hood.
Your set-up is about as hard as it gets though. The kitchen is on a lower floor and because of the porch is not really on an outside wall. Vent dimensions are usually 7" to 8" if round or 4" x 10" if not. The vent fans are not that powerful so total run is recommended to be under 8'. These specs can vary a bit depending on what range hood you have. Still, trying to find as straight as possible run will be difficult. Probably the most direct would be to exit through the wall behind the hood and then turn upwards to go through the porch roof. Downsides are that you may have to build a small chase to cover the pipe from the porch area and of course the fact that you have added a new roof protrusion that needs to be flashed correctly to work.
An alternate plan would be to find a better recirculating hood that has better filters. There is certainly a difference between your typical $59 hood and one that costs several times that.
Oct 26, 2013, 10:54 AMMary A
Thanks, Jaybee. Our porch is not enclosed and has a ceiling and roof. Would it be possible to vent it between the two (you wouldn't see it) and vent out the porch roof?
Oct 26, 2013, 12:42 PMJaybee
That should work. The only complication is that there is likely a solid ledger for the porch that you'll have to cut through. That, combined with whatever structure is in the house walls at that point, can make hard to cut an 8" hole.
The whole goal is to keep the duct run as short as possible with as few bends as you can get away with.