I am putting about 650 cfm (1.5 ton, 3 speed variable air handler) into a 600 sf room (half shaded building, new construction w good insulation). Can someone tell me how many 4" x 12" floor registers this would require? I am also hoping to keep the noise levels minimal. Many thanks! Claude

We noticed a terrible smell in our kitchen Monday night 2/14. By Tuesday night we had narrowed it down to the cooktop downdraft vent. So here is what's bizzare...when the vent runs there is NO smell. But within 20 minutes of turning it off the smell returns. We have taken the vent grill cover off and the filter out and cleaned both. Upon putting it back together the smell returns within 20 minutes. It smell like cooked broccoli to a certain degree which really smells terrible when cooked in the microwave. My husband thinks something has found its wat into the downdraft and died but I am no convinced of that yet. We have NO idea where the downdraft exits the house. My husband has been on the roof before and says he knows where both of the bathrooms vent to the outside but not the downdraft. I phoned my HVAC guy who was supposed to come yesterday but I would like to know if I am even calling the proper service people in? Has anyone ever heard of something like this before???