Should I vent kitchen hood to outside or recirculate when using an ERV
I am building a new ADU, which will follow most principles for a passive house (air sealed with Zip-R, etc.) and include an ERV system for air exchange.
I am trying to decide whether I should vent my kitchen hood to the exterior or just use a recirculating. hood. I know conventional wisdom says vent to exterior, but I the setup I am envisioning I am having a hard time understanding why.
– It is an all-electric house with inductive stove top, so no carbon dioxide, etc. to worry about.
– I plan on installing an ERV with a boost mode. This would be set to switch on automatically when the hood is on, or when a particulate detector is triggered. Yes, I know boost mode will not draw nearly as much air as a range hood, but still reasonable to expect after 30-60 minutes it will have a exchanged a good portion of the air in the space.
– Assume I buy a good recirculating hood; it will have grease traps and filters. No, it will not clean the air as well as replacing it, but I have a 600cfm vent hood in my house now and it’s not as if there aren’t cooking smells (my cooking doesn’t smell that bad anyway).
– If I exhaust to the outside, I have to have a make-up air system, which adds complexity, you need to temper the incoming air and not have it blow everywhere, etc.
– The only thing I can think of that might be an issue is humidity from steam, but is it really going to be that bad with the ERV on. Maybe it’s a little humid for 30-60 minutes?
– BTW I live in Bay Area, California, so I do not have a lot of extreme climate issues or humidity to worry about.
My question is, am I missing something?
Replies
For your ADU in a passive house setup with an ERV, using a recirculating hood is feasible given your considerations and climate conditions.
In my experience recirculating hoods do just that, re-circulate the smoke and grease. Since you are building new its pretty simple to vent the hood to the outside, add a make up air sensor/damper/duct work. And if need be you have your ERV for back up.
Recirculators are vastly inferior in my experience (having lived with one). It's especially problematic when cooking with high heat (meat, charring vegetables, etc.). I'd do the upfront work of solving for this unexpected venting, rather than the ongoing annoyances of dealing with a smokey home.
Your makeup air system can be cracking a window open. Vent the hood to the outside and fry up some fish.
In an all electric home with an induction cooktop a recirculating range hood is fine.Bolts Australia