Make-up Air for Kitchen Hood Exhaust

You could try sealing your windows and doors better with weatherstripping so they don't allow outside air into the house I'd try that first as a fairly low cost fix compared to what you are thinking about.

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Y ou could try sealing your windows and doors better with weatherstripping so they don't allow outside air into the house

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The air would then come from somewhere else. I've seen houses with large hood fans pull sheetrock dust from behind receptacle boxes in the kitchen.

Not sure how to do it post-construction, but I have a large hood vent and the AC guys cut in a make up air vent from the AC system to supply air for circulation. It has a flap that opens when the fan comes on.

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Not sure how to do it post-construction, but I have a large hood vent and the AC guys cut in a make up air vent from the AC system to supply air for circulation. It has a flap that opens when the fan comes on.

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That's what AI is suggesting too, but I'm not understanding if it's an HVAC system with ERV (fresh air intake to balance air pressure) or a standard HVAC - sealed system. AI is saying it works with a sealed system.

Logic states if I'm pumping 500 CFM of air out, it creates a vacuum and has to draw in air from somewhere. AI says the bypass you describe allows the exhaust to suck air in from every room in the house equally from the ceiling returns.

So I was adding a high cam vent. Anything over 400cfm needs a make up air system in GA. If you don’t have it you could be pulling shite from your water heater etc. apparently it can cause a carbon monoxide issue. Every solution seemed expensive as hell.

I believe the correct way to do this would be to install a dehumidifier in your attic that also has a makeup air inlet. Has a control switch that opens up the damper for the dehumidifier to pull in the makeup air and dehumidify it prior to dumping it into your air conditioning duct work. Look up an ultra air 98h. There's more literature on there spec sheets.

Malliard, that's probably the right way to do it, for sure, but dang that's very expensive for make up air. Like Boss said, $$$

Maybe I could do something like Gumbo suggested and put the MUA in the front of the hood. Maybe rig up some sort of dryer vent style system with the intake installed in the soffit outside with some sort of reverse flap or motorized intake. Have flex hose run to front of range hood.
There would be a lot of blowing back out the outside air which would only circulate near the hood, but mischief may be managed by containing it to the hood area?

The house was designed with one of those recirculating hood filters, it didn't exhaust outside, just into the cabinet through the grease filters. I added the external a few years ago. Noticed it sucking stuff in when the hood was on through various cracks only recently. I have a CO monitor, and it never kicked off. But have a house with allergy people and am trying to find a cheaper solution to this "problem".
Like Boss said, GA has it as part of their code for a reason. Supposedly if the CFM is strong enough you can cause a backdraft from the furnace and water heater in the attic causing uncombusted gasses to seep back intothe house.

From Google

Types of Makeup Air Systems1. Passive SystemsPassive systems are the most common and cost-effective approach. They consist of an exterior wall hood, an intake duct, and a motorized damper. When you turn on your range hood, an interlocked sensor or pressure switch detects the negative pressure and automatically opens the damper to allow unconditioned, outside air to flow naturally into the home.Pros: Low initial cost, minimal mechanical maintenance, simple setup.Cons: The incoming air is the same temperature as the outside, which can cause drafts or freeze pipes in cold climates.2. Active (Powered) SystemsActive systems use an intake fan to mechanically force fresh outdoor air inside. These systems often include a filter and an inline heater to "temper" the incoming air (warming it up before it enters the living space).Pros: Highly controlled, filtered, and tempered air maximizes comfort.Cons: More expensive to purchase and install; requires regular filter replacement

Maybe you could do something like the passive system have it done to somewhere close in your kitchen.

It’s going to take time to reduce the humidity of outside air though. That’s not going to happen as fast as you are blowing it out, unless you pulled 100% through a dehumidifier/ AC coils. But even then I don’t think systems are 100% efficient in reducing humidity in the summer in the south I doubt you go from 90% humidity to 55% with one pass through of the air. I mean your home hvac system has to run almost continuously to reduce the humidity to comfortable level.

Long story short, outside of an expensive system I’m not sure this is something worth stressing about OP. It is what it is, like kids leaving the door open every time they go outside.

I do know of a ultra air 98h that is close to your location that has been lightly used and is no longer in use. It does have a filter to clean the air prior to coming in the house. It also has its own humidistat so you can control it independently from the air conditioning. Let me know if you're interested.

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You aren't running all your burners on high at once to need 500 CFM, Speed control is what is needed

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It's less about the burners and more about the cooking/smoking/odors for some people.


OP, look into getting an ERV installed.