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Have a home with no vent hood. This is an interior wall. It has the vent pipe for a down draft under the cooktop. The previous owners must have changed out the cooktop that had a down draft in it to a Nice Viking cooktop with no down draft. I would like to keep my cooktop and put in an overhead hood. can this be directed down from the overhead hood to the pipes for the downdraft? I don't like the way a downdraft works and I like my cooktop. Does this just vent under the house?
I head downdraft "hoods" are horrible in that they don't work well and are incredibly nasty with oil byproducts coating its interior (which I interpret as a food haven for cockroaches) which is impossible to clean... Over the range hoods don't actually work since it just recycles the air back into the kitchen (I used to have this and can tell you, its horrible)... what I did was create an over the range vent which required them going into the ceiling and putting ducts to the roof outside... I know my contractor didn't want to do it simply for the vent and refused to do it as the money doesn't equate into the work involved... we did an entire kitchen remodel which "finally" interested him enough to do the ventilation...
I want an over range hood that vents outside. Just don't want to go through the second story and roof. Want to know if over range hood can go down and then outside. Have the vent pipes under my cook top.
Have the same problem. We just moved into a beautiful home with many nice features, but the kitchen isn't one of them. We will be replacing every appliance and the cook top (which is a 4 burner in a huge house built less than 10 years ago). When we mentioned there is no vent, the previous owner told us "yes, there is, it's on the microwave above the burners". Umm, no......
Ours also has what looks to be the tubing for a downdraft hood, but like PP above, I heard they don't work so well.
Last edited by Texas Ag 93; 07-07-2015 at 05:19 PM..
That is why I don't want to replace my gas range with one the has a down draft built into it. had one in our previous home and it was really bad. If you turned it up on high it would mess up the flames on the burners. on low it didn't do much but make noise.
You can do this. It's just a matter of connecting the hood above the range to the ducting. You will need to remove drywall from the area behind the hood and possibly a cabinet depending on the way the hood is connected and put it back when done. If you have a backsplash you'll have to either get access from the back of the wall or remove the backsplash material and replace it.
It will probably not work quite as well as a hood vented up and out becaue you are working against the hot air wanting to rise and will probably have a more convoluted pipe pathway but still should perform better than a downdraft. Any HVAC company could do it.
It would probably work best with a hood with a remote fan at the end of the duct run and Viking makes hoods with seperate fans so it can match your range. There are also other manufacturers of similar hoods.
Now, the other issue is if the fan is over 450 CFM and it almost certainly will be, code requires make up air be provided. That should not be a huge deal either and will make the hood work better but will mean ducting, likely into your HVAC unit or to a grille under your range.
You can run your duct downward for a residential application but how you run the exhaust duct (size, changes in direction, etc) may impact volume and noise. The duct must terminate outside (not under a deck) and all clearances to openings, windows, etc must be adhered to to comply with the mechanical code that your city has adopted.
M1503.1 General.
Range hoods shall discharge to the outdoors through a single-wall duct. The duct serving the hood shall have a smooth interior surface, shall be air tight, shall be equipped with a back-draft damper, and shall be independent of all other exhaust systems. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.
Exception: Where installed in accordance with the manufacturer’s installation instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.
M1503.2 Duct material.
Single-wall ducts serving range hoods shall be constructed of galvanized steel, stainless steel or copper.
Exception: Ducts for domestic kitchen cooking appliances equipped with down-draft exhaust systems shall be permitted to be constructed of schedule 40 PVC pipe and fittings provided that the installation complies with all of the following:
1. The duct is installed under a concrete slab poured on grade;
2. The underfloor trench in which the duct is installed is completely backfilled with sand or gravel;
3. The PVC duct extends not more than 1 inch (25 mm) above the indoor concrete floor surface;
4. The PVC duct extends not more than 1 inch (25 mm) above grade outside of the building; and
5. The PVC ducts are solvent cemented. M1503.3 Kitchen exhaust rates.
Where domestic kitchen cooking appliances are equipped with ducted range hoods or down-draft exhaust systems, the fans shall be sized in accordance with Section M1507.4.
M1503.4 Makeup air required.
Exhaust hood systems capable of exhausting in excess of 400 cubic feet per minute (0.19 m[SIZE=2]3/s) shall be provided with makeup air at a rate approximately equal to the exhaust air rate. Such makeup air systems shall be equipped with a means of closure and shall be automatically controlled to start and operate simultaneously with the exhaust system.
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Just looking at the standards. The reason I say 'no' on installing due to the amount of turns required. Generally speaking all the exhaust fans I have seen are either straight up and out, or 1 90deg turn (or less) then out. That would seem typical for a standard rated CFM blower.
In this case you are going 'up', looping back at least 180deg to go back down, then possibly another turn depending on how the downdraft vent was installed? Me thinks you would need a bigger fan than normal, lol.
Plus the grease build up- It'd be a nightmare! I've had to clean my exhaust vent in the one house we owned that was built in 1972. It was up, turned 90 and went out the side of the house. It was NOT fun, lol.
In this case you are going 'up', looping back at least 180deg to go back down, then possibly another turn depending on how the downdraft vent was installed?
The biggest issue is the "back down". I'm envisioning connecting the new top duct and the existing down draft duct to a 3'' x 12" concealed wall stack, which is only good for about 150 cfm. 150cfm? Why bother.
Can I? Yes.
Should I? Probably not.
After the dust settles, the OP will realize that he/she would have been more happy with a roof termination or even a down draft than a Franken draft.
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