What do we think about back return plenum systems like

https://larkinhoods.com/pages/Item.aspx?ItemID=135

Seems easy to install, negates back wall combustibility issues, reduces need to temper the mua?

Pretty affordable too, all things considered.

I’m mostly thinking of this for the commercial kitchen I’ll be building in the coming year. But the principle of introducing MUA behind or under the range is something I’ve been thinking about at home. There, I am thinking about a floor register under the range. My thought is that air will flow up and around the range, and be pulled upwards around the cooking surface, creating something of an “air curtain” to further contain effluent ? The air would not have much opportunity to mix with room air, thus tempering might be less/not important. It’ll be easy to bring air in through a basement duct and blower.

I have not been in a hurry to install MUA, since the gas furnace and water heater are both power vented thus unaffected by the hood, but backdrafting the fireplace when I forget to crack the kitchen door gets irritating. Even when there is no fire in the FP, pulling hot or cold air into the living room is also irritating.