On Jul 12, 2:00 pm, Terry wrote:
http://www.cetsolar.com/ventcover.htm

Anyone using these?
Should I cover the return air?

Not using them but I do like to close off some of the vents in the
bedrooms to save money/energy by only cooling the occupied parts of
the house during the day. I know you're not supposed to close off too
many vents though as you can create too much backpressure and burn out
your blower motor.

I don't think you should cover the return, as I think that would
stress the blower even more.