New Code: Makeup air required for kitchen hoods
ARMANDO COBO
| Posted in Green Products and Materials on
The 2009 IRC requires makeup air (MA)with kitchen exhaust hoods over 400 cfm + it needs to be operated simultaneously with the fan… I’ve tried unsuccesfully to find a 1200cfm hood with built-in MA, like in commercial kitchens. To provide temporary MA with the hvac system + the house (6000 sf) it would be to big of a system. Do you know of an independent MA system for this home. Wolf do not make hoods with built-in MA.
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Replies
Armando,
Shelter Supply sells two sizes of makeup air units. The big one is rated up to 535 cfm:
http://www.sheltersupply.com/corporate/default.asp?cwpID=16
http://www.myworksite.com/shelter/htmlArea/files/documents/52_makeupair.pdf
Thank you Martin. Yes, I've seen that unit, but again, I need to get to 1200 cfm. Wolf's warranty voids if I hardwire directly to their hood. I had talked to the builder about using that same unit for half of the MA and the other half with the hvac system, but it would not be wired together. Maybe that's the way I need to do it for now.
Armando,
Don't do it! 1,200 cfm is nuts -- violates several important principles of energy-efficient building.
I've said it before, and I'll say it again: powerful kitchen exhaust fans are INCOMPATIBLE with energy-efficient residential construction.
Well, I feel I'm in a pickle... you can't tell your client NO, all I can do is advise. The stove the owner wants to use REQUIRES 1200 cfm hood... and as far as incompatible, it's been done avery day in restaurant blds., I just don't want to use a commercial hood UNLESS I have to. Mucho size & $$$$$$.
Armando,
If the client wants a monster stove and a monster exhaust fan, and if the client has the necessary big bucks, they'll probably get what they want. But they won't get a green home ...
Yup, I agree... I'm just asking in case anyone has had this issue and how they solved it. Thanks, AC
You most certainly can. If you feel it's simply wrong for the earth, its climate and its living inhabitants, then you have a moral obligation to say no. If you don't, then you're complicit.
Robert,
I guess I haven't got wealthy, famous or arrogant enough to tell my clients NO and take a hike, especially in this market. I believe my job is to recommend best practices and find possible solutions to a problem and I DO design very high end green building, but I will refuse to become the size police or a green freak that will "force" a client into my way of thinking or else... maybe that is why so many people get turned off by green building. If it works for you in Vermont I'm happy for you.
Armando,
I agree with Martin about the contradiction of an excessive range hood being installed in a "green" home. But sometimes you gotta do what the CLIENT wants...
I think in previous posts you mentioned you were in Texas, but Electro Industries manufactures some make-up air heaters that provide up to 1580 CFM. You may be able to purchase the units without the heating coil.
http://www.electromn.com/gen/makeup_air.htm
Thank you Brett, this could be a good solution. I'll follow up.
Armando,
You missed the point. I'm not by any stretch of the imagination wealthy or famous. And what some confuse as "arrogant" is merely integrity. In fact, my integrity requires that I live on a subsistence income because I simply will not be complicit in what I know to be wrong for the world, regardless of the personal consequences.
There is a solution to this and that is install a small o/a duct to the return air plenum of the central air/heating system with a motorized damper to open when hood switch is engaged to bring a signal wire to the units high fan input. Most newer air handler have inputs for this, if not a relay can be installed. A local HVAC contractor should be able to help you achieve this. On another note green building and design does not mean you eliminate your footprint. It's designing to your comfort level with having energy efficient ideals in mind opposed to just building with maximum comfort with no energy efficient ideals.
Mechanical Engineer,
Thank you for your solution. We can not do that because to install a 1200 cfm MA system requires a 10"-12" duct and to combine it to the MA of the house would be too much MA for the air handler, and it would run the heating and cooling system unnecessarily. Also, it would require to upsize the mechanical system.
We end up installing a separate tempered MA in the kitchen that would have the vents near the stove, providing the necessary MA in a closed loop. Doing it this way, it would not “tax” the house air or mechanical systems. Similar to what is done in commercial kitchens but at a much reduced cost.
Armando,
I am curious... when you say "tempered MA"
can you describe it in more detail?
are you saying it is precooled or preheated and "pre-dryed"
How much will it cost to install?
How much power will it use when operating?