Recommendations for Home A/C Filters

[danski0224]

The spec will be on a tag on the air handler. For my Carrier it states .5" WC and then in the installation manual it states that includes .10 for the internal fiberglass/horsehair type filter, which if removed can be added back to the total. So for my Carrier it is .50 + .10 since there is no internal filter. The pressure below the air handler includes the inlet air filter(s) The pressure above the air handler includes the evap and ducting resistance. Combined they cannot exceed .60" WC on my unit.

The decal that is in your post indicates otherwise, as it states "Max External Static Pressure" (AKA: TESP). That decal is clearly from a furnace, not an air handler. Minor nit pick, but it makes a difference.

Can you take a picture of or scan the language provided that states that the manufacturer 0.10" wc filter allowance can be added back in, and post it?

The filter is external. "Internal" filters are typically on an air handler (as in, not a furnace) cabinet, but even air handlers will usually show a TESP number that already has the evaporator "taken out" as it is part of the cabinet with the fan (TESP may be 0.3", for example).

If you are running at 0.060" TESP, then that is, by most accounts, a good system. What is your limit for the air filter? As the air filter loads up, TESP increases and airflow goes down with a non-variable speed (VS) blower motor (this includes multi tap ECM motors). Amp draw goes up as a VS speed motor attempts to maintain the set airflow. Do you change/clean the filter at 0.70" TESP, for example?

 

[danski0224]

upstream pressure is usually practically the same as atmosphere.

Um, no.

 

[FredWanaker]

 

[Kuma601]

Do any of you track the filter replacements in hours? Before with the old thermostat I'd periodically check then swap when the filter showed lightly gray. The new thermostat tracks system usage so it shows the filter is at 100 hours. It still appears white-new and it has been in there since Jan. We didn't need to use the heater to much so from Feb-March there was minimal use. March till end of June the system wasn't on at all.

 

[FredWanaker]

I added one of these and put it in the garage with the hose thru the wall next to the filter, and when it starts to rise too much it is time to replace the filter, or when seven to nine months passes, whichever comes first. Mine shows about .23 when new with AC on (high blower speed), then when it gets to say .28 I change it. A new original fiberglass filter will show less than .10 but it doesn't filter much. The heater fan speed is much lower so the number is lower too.

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