[stephen_g]

The claim on the site is that the heat exchanger base boosts efficiency up to 60%.

You still of course do have the problem that home rangehoods usually aren't powerful enough to create enough air-flow to properly deal with the NOx and SOx produced by burning gas, which turns out to be a big health risk...

[amluto]

Most home range hoods are too powerful. Go to any site that calculates commercial range hood requirements, enter in your parameters, and then try to find a nice range hood that matches. Those 700 cfm or 1000 cfm beasts the appliance stores sell are entirely inappropriate.

There may well be a problem with a poorly designed range hood and exhaust that inevitably isn’t captured. And people might not like using the hoods all the time.