> Mine is also that thick expensive filter - but I think F.W. Wells
No such place exists . Do you mean F W Webb?
As for proper filter length of service. The standard definition for a
tech would be to measure the static pressure drop across the filter to
determine the restriction in the filter ( or dirty coil) Depending on
the design of the system, some homes I have serviced were affected by
a " dirty filter" upon inspection, the a/c coil was filthy and was the
cause of the restriction.
.5 inches of water column is the unicorn ( desired but never seen) ,
but anything within 1.0 and less is ideal. Those of you that have
icing problems and are constantly changing what looks like a kinda
clean filter may wish to have the system evaluated by a competent
service tech that can test the static pressure drop of the return, the
filter , the coil and the supply.... No fair opening all those closed
registers before he gets there......
While I know most people do not have a magnahelic gauge . any draft
meter will work. I have seen some homes that have a green yellow red
gauge in the ductwork. If your spaceguard or air bear filter is
getting dirty and restricting the airflow with 1- 2 months I suspect
that you have a very dirty house with a large amount of traffic or the
home has many holes for intake of airborne debris from the outside.
I have found that most homes can use the standard airbear ( 20x25x5)
or spaceguard ( 20x25x6) The latter of the two now has a cheap upgrade
that runs about 12-15$ I have 4 dogs and I get 4-8 months out of one.
Kris Heikkila