Roger is building a two-story, 3500-square-foot house that will have an energy-recovery ventilator (ERV) and a kitchen range hood. His question is about how this ventilation system will affect the range hood, and vice versa.
“Should one try to install a range hood exhaust with 400 cfm [cubic feet per minute] or less?” he asks in a recent Q&A post. “Would it be OK to install a 600 cfm unit in a home that has an ERV unit? If so, are there any special things to do differently when considering a makeup air strategy for a home that has an ERV with dedicated duct lines?”
An ERV supplies continuous fresh air throughout the house with its own ducts and it exhausts indoor air at the same rate, for balanced ventilation. Range hoods provide relatively powerful spot ventilation when needed, but do not replace that air; they are an exhaust-only appliance. The topic for this Q&A Spotlight is whether those two systems can work together to maintain not only fresh air, but also to balance pressurization of the house.
Nicolas Bertrand wonders whether the ERV could be installed in such a way that it provided makeup air for the range hood. “Do they have a function where they could run as an inlet only for the house and have the exhausts blocked?” he asks. “This way the hood could do the exhaust work and the ERV supply some of the required air. I know a dedicated return-air supply is normally required for a tight house, and sometimes with an inline heater if it is cold outside, but maybe there is a way to rig the ERV to take its place.”
Probably not, replies Malcolm Taylor. He knows of no ERV that can run in an unbalanced mode to provide…