Make up air and who is responsible 

 TONER Point of Consideration

Make Up Air and Who is Responsible 

All Hood Vents with over a 400 CFM rating are now required to have a Make Up Air system. We need a 1 for 1 ratio above the 400 CFM mark. An average 48" cook top will require a 1400 CFM hood. Therefore, we will need a 1000 CFM Make Up Air system. 

That system will include: 

1. At least (1) if not (2) Make Up Air dampers. 

2. The damper will either be in the attic or, most likely, in the ceiling. 

3. An access door will be needed for the damper. 

4. The outlet for the damper will be a 12x12 stamp face grill located within 10' of the cook top. Normally, in the kitchen ceiling. 

5. The intake will be another 12" louver (per system) on the outside. This must be terminated sidewall not off the roof. 

Recently we asked 6 appliance providers why they are selling commercial appliances in residential homes and if they planned to manufacture residential look alike with less CFM need. They said that they are not liable for the CFM need and that the HVAC Contractor is responsible. They have no plans to help with this issue. 

Most HVAC Contractors do not understand the rule or how to apply the Make Up Air system. 

Neither wants to touch each other’s product to wire it up out of fear of liability. 

The person who suffers the most are Builders, Architects and Homeowners. Lack of Make Up Air or the misapplication is a leading cause of some very violent and destructive Forensic issues. They range from mechanically driven humidity and water damage to major mold infestation and destruction of building materials. 

Please make a point to involve us earlier than later and educate your clients on these issues. It is our responsibility to educate them as to what their options are. 

Thanks –Toner 

TONER Home Matters 

Coryne Rich