make up air

we are nice and toasty in a old building right now and summer is coming!
I am going to need a better exhaust SOON! how important is a make air and how will I know if I need one?
plus I have a MM 320 single

Hi there,

Examine your state and local requirements. If you are still in doubt, ask your Fire Department to take a look at your setup.


Or George Mills.

Hes our Ventilation/Makeup Air unit expert.

Ventilation is a critical element in the equipping of a pizza shop. Health and building departments have stringent rules as to the amount of air to be exhausted by various styles of hoods. It is also a requirement that the same amount of air exhausted from the building be brought back into the building at or near room temperature.

The air that is brought back into the building is referred to as make up air. A properly ventilated building has slightly higher air pressure than outside air pressure. If outside air pressure is higher than inside doors are hard to open and when opened outside air rushes in bringing dust, dirt, humidity, hot and or cold outside air making uncomfortable drafts. Gas fired appliances can starve for oxygen and not operate properly. Cooking odors are retained in the building and other problems arise.

The required make up air can be provided in two ways. A separate make up air unit can be installed or sufficient air conditioning can be provided through the Heating & cooling system to supply the required make up air. We prefer the use of listed hoods and sufficient air conditioning. Cost wise the listed hoods and sufficient air conditioning is about the same, or a bit more, as unlisted hoods and make up air systems but there is a much better comfort level working with sufficient air conditioning and substantially less cost to operate.

In some parts of the nation where the temperature never falls very low a simple filtered fan system that brings in outside air can be used. Unfortunately that type system brings in a lot of extremely hot air during the warmer part of the day and the air conditioning system cannot cope making the shop very uncomfortable to work in. Most all makeup air system do not cool summer air just warm winter air making the shop extremely hot in summer. In the very few dry areas an evaporative cooler might be used. We do not recommend the above types of make up air systems.

If Mr Red barn will indicate the type of hood he has and the measurement of the outer perimeter of the hood I will calculate the cfm requirements and make recommendations as to exhaust and make up air.

George Mills