Currently I have someone at home that vapes but only in his room. I do not smell anything around the house unless I open his door. IF I place a return in each bedroom of the house with the filter at the air handler will everything remain the same as far as you can't smell it outside his room or will the return in his bedroom make it worse around the house?
I would think the air would dilute any smell by the time it got to the furnace, but you could install a dampered return air grill and have them close it when they vape.
Or install an electronic ionizer near the return end by the blower wheel to eliminate any odour
Or tell them to vape outside...