When I built the house 18 years ago:
Re: unfinished basement in Atlanta, Ga.
Company "A" put '1' return vent in the basement.
Company "A" put in 1 supply vent
18 Years later:
Basement is still unfinished. Company "B" replaces the old tired Goodman HVAC heat pump system (3 tons)
Company "B" permanently does away with the return vent in the basement. His rationale was you don't need it and it will pull in "basement smell" into the system.
Company "B" leaves the 1 supply vent in place.
I do use the 1 supply vent to help cool the basement and it seems to deter the HVAC pipes from sweating.
At no time did company A or B make any reference to pulling humidity out of the basement. Basement does have a boat door and it is opened and left open while I cut grass or do yard chores. (Wish I could say it is because I have a boat but I don't!!)
So what do you Pros do in a basement? Should it have a return or not? Thoughts? Opinions are appreciated.
Since it has a supply,it needs a return or a return path(leave the door between the home and basement open to provide a path),to "balance the air flow.
The fan supply air cfms(quanity) always equals the return air,regardless of where it goes,or comes from.
Without a return air duct or path,the supply air to the basemnet will make it positive pressure,causing exfiltration of conditioned air,a waste of money.
The living area return is "looking " for that missing supply air,so it is negative pressure,causing Infiltration of unconditioned air from who knows where,a waste of money,and poor for comfort and indoor air quality issues.
Try this test:
Stand where you can feel the basement supply with your hand,and have someone open ,and then later close the door to the living area.With it closed air flow will be reduced ,with it open air flow will increase.The difference between the two is due to increased static on the fan with the door closed ,which is all or in part a reduction in total air flow thru the the equipment,another waste of money.
Close the the boathouse door ,while mowing,more money wasted!!LOL