On 9/30/2015 11:40 AM, trader_4 wrote:
On Wednesday, September 30, 2015 at 2:15:43 PM UTC-4, Bill Gill wrote:
Everybody says to inspect your furnace filters, but they don't say what
to look for. On the TV news they always say it, then show a filter that
is completely clogged. Obviously they should be replaced before that.
So what should I look for to decide if I need to replace them. I have
been replacing them every 3 months, but when I do I can barely tell
the difference between the old ones and the new ones.

Bill

If they are conventional filters, you can see dirt, they look
darker than a new one. Mine can easily go more than a year.
It depends how dusty your environment is, if you have pets, etc.
If you can barely tell the difference, you're probably changing
them too often. The typical 1" thick fiberglass type is almost
worthless. It will hopefully stop some stuff, but to do any
kind of reasonable trapping, you need one of the 4" thick ones
or an electrostatic.

Bull****