On Sun, 10 Sep 2017 12:53:05 -0400, Congoleum Breckenridge
wrote:

On 9/5/2017 9:24 PM, trader_4 wrote:
On Tuesday, September 5, 2017 at 7:34:37 PM UTC-4, wrote:
On Tue, 5 Sep 2017 07:17:31 -0700 (PDT), wrote:

On Tuesday, September 5, 2017 at 8:20:04 AM UTC-4, TimR wrote:
The purpose of the filter is to protect your coils or heat exchanger, not to clean the air for humans.

It seems reasonable to me that a dirty filter will catch more dust than a clean filter and be better for your coils, up until the point it impedes air flow.


yeah i agree,

and if you keep a thermometer in the duct to monitor the air temperature, if the air flow is significantly impeded, the air temperate will rise in the heating season or drop in the cooling season.

If the duct air temp is normal , the air flow is normal.

m



A differential pressure tester or manometer across the filter gives a
much better indication.

Agree. You have one on yours? I've never had one on any furnace
I've owned or seen. Of all the people who read here,
how many do you think have one? Nuff said.

https://www.alpinehomeair.com/viewpr...SABEgKDWPD_BwE
At least as many as those who have a thermometer on each side of the
filter. Filterminders (donaldson) are common equipment on engine air
filters

Also Google CleanAlert and Filterscan

or check
http://www.cleanalert.com/blog/how-t...filter-monitor

Unlike some of you guys I don't just pull this stuff out of my ass.