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Rich Riddle
07-19-2016, 5:52 PM
I am getting ready to place a vent in the kitchen at the farm. Previously he owner had the stove vent literally built into the ceiling set 7' in the air. It was controlled via a wall switch. Though the owner hooked the vent to a flex hose, it simply vented further into the attic, not out the roof. You should have them vented outside if you choose that type of vent, correct? It's not really close to anywhere that would allow you to vent it outside. Please correct me if I'm wrong.

I included a photo where you can see the previous "vent" built into the lowered ceiling and one outside that clearly shows no vent in the roof other than the water vent.

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Kev Williams
07-19-2016, 6:28 PM
Most stove "vents" and over-the-stove microwaves just move the air back into the kitchen after passing thru what can only barely be called a 'grease filter'. The only actual outdoor vented stove I've ever had was in a motorhome!

The house I'm living in now, built in 1966, my parents moved into in 1969 (when I was 14)... It had a twin to the bathroom ceiling vent above the island stove, and like the bathroom vent it just vented into the attic.

My dad removed the vent and sheetrocked the hole when he installed a JennAire cooktop back in 1980-- which I replaced with another JennAire about 3 years ago. (still have the old one, works great).

Only time I remember my mom using the JennAire blower was when grilling or something was smoking. We don't use the blower much either. And after 47 years, there's no indication anywhere the cooking has rarely been vented anywhere ;)

Lee Schierer
07-19-2016, 7:11 PM
Yes a range hood that does not recirculate should be vented all the way outside not into an attic or soffet. Grease and moister from cooking should not be pumped in attic spaces. Also, flex hose is not good for range vents. Outside vents should be equipped with a damper that prevents back flow of air when the wind direction shifts and the fan is not running. Vent runs should be as straight and short as possible. Bear in mind one 90 degree elbow is essentially the same as adding 10 feet of straight pipe.

Jim Becker
07-19-2016, 8:50 PM
What Lee said. In fact, in some areas, code requires venting a range hood outside. I actually had to design and contract for custom duct work to vent our 1200 CFM hood when I renovated our kitchen back in 2003 so it would fit in the odd-dimensioned space between joists to the outside wall and then transition through the wall to a standard auto-opening vent register.

Brian Elfert
07-19-2016, 9:00 PM
I had an outside vent added to my kitchen last fall. The HVAC contractor suggested going above the cabinets and out the wall instead of through the roof. He said it would be one less thing to leak on the roof. I still have to box in the area o above teh cabinets to hide the pipe.

Mike Berrevoets
07-19-2016, 9:53 PM
we had a range vent in our kitchen. Always wondered why it didn't really get rid of the cooking smells. When we had siding replaced I got a call from the siding guys. They asked if I wanted them to put a vented soffit in where the range vent exhaust went out the overhang of the second floor. It had a solid soffit. The range exhaust fan had been exhausting to the kitchen bulkhead/second story joist bay since 1975. (We bought about 10 years ago)

im doing the kitchen remodel now and tore out the bulkheads which were also open to the cold air return. So, when we cooked bacon with the fan on and the furnace kicked on it distributed the bacon smell throughout the house. Don't get me wrong, I love bacon but not when the whole house smelled like it for a day or two.

It is corrected and exits out the wall and works surprisingly well now. :)

Alan Rutherford
07-20-2016, 11:49 AM
What Lee said. In fact, in some areas, code requires venting a range hood outside. I actually had to design and contract for custom duct work to vent our 1200 CFM hood when I renovated our kitchen back in 2003 so it would fit in the odd-dimensioned space between joists to the outside wall and then transition through the wall to a standard auto-opening vent register.

I did this years ago in a basement unit. Did it myself and it was a lot of work, but it's important to vent outside.

As for venting into the attic, it might be better to recirculate. I've also had some surprises with bathroom fans.

Here in Florida much of the year every cubic foot of air-conditioned air we blow out is replaced with a cubic foot of outside air with temperature and humidity both over 80. I'm thinking about a way to duct outside air in near the stove so that's what gets blown out.

Lee Schierer
07-20-2016, 4:11 PM
OUr church has a commercial range hood that brings in outside air so there is no net loss in the room, only the heat is removed.

Jim Becker
07-20-2016, 9:01 PM
OUr church has a commercial range hood that brings in outside air so there is no net loss in the room, only the heat is removed.
That's a feature I wish mine had...when it's up at the highest level, it moves 1200 CFM and it clearly affects how air moves around the house!

Rich Riddle
07-20-2016, 11:15 PM
You folks convinced me to find a venting one that can at least vent a minimum of 200 CFM, likely a lot more. I read some articles about the recirculating types and they were universally bad reviews. One more project.

Jim Becker
07-21-2016, 9:50 PM
Rich, the more BTU your range puts out will affect the minimum CFM you need. My original DCS range after the 2003 kitchen renovation had a grill and that alone pushed the CFM requirement to 1200. But honestly, I wouldn't want less with the current Thermador (no grill but more BTU)...it really helps with both exhausting what rises from the work, it also works as a grease filter. It's pretty amazing what gets pulled out of the air in a couple months' time... ;)