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What Is Make-Up Air? (Definitions / Solutions)

Steve Sheinkopf  |  June 05, 2012  |  2 Min. Read

Ventilation  |  Make Up Air  |  Broan

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In newly engineered homes with hoods over 400 CFM, there is a new code dictating air replenishment. Although this code has been on the books since 2009, there are inpectors now enforcing it.

Code 1503.4:

"Exhaust hood systems capable of exhausting in excess of 400 cubic feet per minute (0.19 m3/s) shall be provided with make-up air at a rate approximately equal to the exhaust air rate. Such make-up air systems shall be equipped with a means of closure and shall be automatically controlled to start and operate simultaneously with the exhaust system."

Simply put, air needs to be replenished or “made up” or compensated for the air lost through ventilation.


Newer energy efficient, “tight” or “green” homes are well air-sealed so outside air will have more trouble finding a way in to replace exhausted air, as opposed to older draftier homes. So what happens is your house depressurizes. Hood vents can't push out air, because there is no air in your home to replace.


It is not a very difficult fix. You simply need air to replace the exhaust. Back when I was specifying ventilation, I would always recommend a damper on the wall cap to prevent cold air from infiltrating into your home.

Now with the new codes, the damper is in-line or in the duct itself and is wired to a Universal pressure regulator. The regulator opens and closes the damper depending on how much air is exhausted. The wall cap simply lets in air.

The Tools

If it sounds complicated or expensive, it really is not. Broan manufactures three simple, inexpensive tools to satisfy the code. The cost is less than $300. Have a look below.

broan make up air options

Helpful Impromptu Video


You still have to duct properly using at least 6 inch duct, and up to 10 inch in pro range installations, with the least amount of turns possible. It is way easier to plan for make-up air before construction then installing afterwards.

Read more about ventilation by reading the Yale Ventilation Buyers Guide. Over 100,000 people have downloaded a Yale Guide.


A few review sites have placed this at the bottom of their articles. So here is our take: Our mission is to find reliable products for you to buy. Other review sites may say this as well.

However, we don’t love every product. Quite frankly, it costs us way too much money in repair costs to support less reliable brands.

In fact, we sell fewer brands than most appliance stores. Here is why:

We feel it is our responsibility to repair your appliances after you buy them.

We now have 30 service technicians, each averaging 8-10 calls a day Monday through Friday, plus another 110 on Saturday. That's over 30,000 service calls logged in one year.

The labor rates of fixing an appliance do not come close to the true cost in any product’s warranty period.

That is why no major retailer has a service department. It costs too much labor, money and time.

Our Blog is a bit different than most others you will read. We cannot write glowing reviews of unreliable products.

Hopefully, the bloggers and organizations who write such glowing product reviews for every brand consider servicing these products first. Only then they will understand the consequences of their marketing.

Steve Sheinkopf

My goal has always been simple: I want Yale to be the best retail experience anywhere. I have tried to create a compelling environment for customers and employees alike.

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