C W Burfle posted:How old is "older"? I've been in homes built before central air conditioning was common that had returns in each room. And I've been in homes built with central air that had a single central return.
I've long suspected that building with one central return was a cost savings.
I never felt it necessary to force cold air down into the basement. Cold air is heavier than warm air and will naturally flow down.
CW, without getting into "rivet counting" I would venture an opinion that prewar (WWII) houses would have no return air in every room, After the war houses generally had at two return air (one for the first floor and one for the second floor) but they were not necessarily tied directly to the furnace. This process utilized the basement as a "plenum", a term common in HVAC that can loosely defined as an open space used for air conveyance.
And, I am not proposing to introduce "cold" air directly into the basement. Rather, the cold or hot air form the furnace (depending upon the season) is mixed with the house air and returned to the basement through the plenum space (the whole house) down the stairs and into the return air grilles in the basement. This has the effect of indirect heating, cooling and dehumidifying the basest space. Sine the house use is continually moved and recycled throughout the entire house, including the basement, the end result will be a much more even mean temperature throughout the entire house.
It does work. Sure, each house may need little alterations to the set upend operation, but the end result can ALWAYS be attained.
