What is the purpose of a return vent?

Quick answer, it recycles and re-heats the air in your home.

It also provides a convenient place for crayons and change to collect.:D

Is that were you save all your change to pay for a replacement for that VS motor?:D

:eek:Crayons work much better in the supply duct cause the melt and smell up the house.

Is that were you save all your change to pay for a replacement for that VS motor?:DSsshhh! If anybody found out I had that much money in there, I'd be targeted for a burglary!

You guys have coin operated heating systems? :D Boy, if I could get my wife to believe that I could afford that Rigid video inspection unit that I want just by cleaning the ducts occasionally! :p

No, kids like to deposit coins into the heating registers, just like some kids put their sandwiches in their parent's VCR's.

Back to the question:

Returns could be better called intakes, but it "returns" air to the furnace to heat.

No intake. Motor burns up. Less intake than motor and duct work can support - motor burns up.

Correct amount of intakes in the right places - comfy house.

No, kids like to deposit coins into the heating registers, just like some kids put their sandwiches in their parent's VCR's.What's a VCR?:p