When searching for information about the necessary CFMs for a range hood, diy.stackexchange.com has two highly upvoted questions:
This is relatively active question, currently with 8 answers and 29 upvotes. There the consensus is that, in many cases, you need A LOT of CFMs, especially with higher BTU ranges. So, for instance, if you have a 6-burner stove with 16k burners, one answer there suggests that you need 1,000 BTUs.
But... there is a substantial issue that isn't addressed (as much as I'd like) in answers to that question, which is better addressed in this question:
There's only 1 answer to this question, but the answerer raises the point that home ranges are infrequently used, and that there is a substantial downside to high CFM range hoods: If you don't provide make-up air (which is expensive), they create negative pressure in a well-sealed house.
Where I'm writing, the building officials use the IRC which requires make-up air that comes on automatically with the range hood, if the CFMs are over 400. So there really is a trade-off here.
What I'm interested in knowing is how one should go about balancing these two considerations, which largely involves information that isn't addressed in the above two questions. I think what's helpful to most people is information that will tell them whether they'll regret undersizing their range hood, and why. Perhaps, a high-BTU stove will heat-up the kitchen too much, or excess grease will be problematic for cleaning, odors from the kitchen will make the house smell like food for a bit, or the air in the kitchen will be unhealthy. I really don't know. What are the concerns, and are they really a problem that would justify the expense of adding make-up air for your hood?
