There have been a number of discussions regarding recirculating cooler
basement air during the AC season. The following is an article
(stolen without permission) from http://ludwig-associates.com/. Jerry
Ludwig runs a Home Inspection business in western New York and answers
homeowner's questions in a weekly newspaper column.

I'm guessing this may start another lively discussion...

Headline: You Don't Want Basement Air Upstairs
Democrat and Chronicle
Column # 27-07
July 7, 2007

Dear Jerry: I have always wondered if there is a way to circulate the
cool, basement air to the upper two floors of the house during the
warm summer months. I have a standard air conditioning system blown by
my forced air furnace. I have pretty good success at cooling the first
and second floors of the house, but every time I go into the basement,
I am amazed at how cool it is and I wonder how I can get some of that
air upstairs.

I do not have any of the dampers open in the basement and there are no
cold air returns directly into the furnace in the basement. Is there a
system that can blow the cool air into the furnace? Is it worthwhile
to put one or more cold air vents into the system in the basement?
Any advice would be helpful and may save me some money.
M. C., via email


There are two basic reasons why your HVAC system does not have
basement returns. One, in our climate, the systems are designed
primarily for heating. This is normally true whether or not one adds
central cooling. Thus, circulating air on the first and second floors
is the primary focus of the system's design.

However, the second and most important reason why there are not cold
air returns in the basement is one of safety. Because most heating
systems rely on natural fuels to provide heat, keeping returns away
from potential hazards in the basement is an important design
criteria.

If there was a malfunction in the furnace's fuel delivery system (gas
leak, oil leak, etc.) fumes from the basement could easily be spread
throughout the house creating a potentially dangerous situation. And,
should a fire develop in the basement, an open return could spread the
fire and/or smoke rapidly throughout the house.

In addition, since the laundry, wood shop, and other places that may
be home to potential combustibles and chemicals such as bleach,
paints, sawdust, etc., are often located in the basement, keeping
these areas separate from the furnace and air conditioning systems is
a very good idea.

Finally, the basement can be damp and musty, even on a good day.
Spreading this tainted air around the house can create indoor moisture
and odor issues during winter months.

Supply registers are often used to supply the basement with warm
circulating air during winter months and I usually recommend that the
warm air registers be kept open during the winter months. Finished
basement rooms are often supplied with warm air registers, although
often some type of auxiliary heat may be necessary to keep the rooms
at a comfortable temperature.

My advice is to allow the basement to remain cool during the summer
while using the air conditioning system as necessary to keep the main
floors comfortable.