One common question we get is do I need make up air? The answer may surprise you.
Make-up air is designed to “make up” the air in your interior space that has been removed due to process suction from exhaust fans. The purpose is to pull in fresh, tempered air from outside your home to replace existing air that cannot be recirculated.
If your intention is to install a recirculating range hood, commonly referred to as ductless range hood you won’t need make-up air. The air simply gets drafted from inside the hood, filtered and then sent back into the same room through ducting/venting in the side of your range hood, or simply out the top. Make sure you review your needs, many times the liner and insert for recirculating requires a non-duct kit. That is just a fancy name for a filter with a few HVAC ducting pieces, and a vent cover. The vent cover will need to be cut out and inserted into the hood during installation. One new popular feature we have added is a a recirculating vent that is cut into the chimney with the router while we are cutting the hood.
If you are venting your range exhaust out of your home you may need make up air. As a general rule, make-up air is required when you choose a range hood insert with more that 400 CFM (cubic feet per minute). CFM is essentially the amount of suction and volume of air movement your insert provides. If you choose a range hood with greater than 400 CFM and you are venting outside, you will need make up air. Due to the complexities associated with make up air, we do not sell make up air as it is part of your HVAC system of your home. You should always consult a licensed HVAC professional when choosing your make-up air decision – this will ensure you meet your local code requirements.