Electrostatic & pleated filters are a death sentence to system performance beause they increase static press. which reduces air flow. This can cause a furnace to overheat and the A/C to freeze up. Unlerss the system was designed them Contact a quailfied contractor who understands airflow performance and static pressures. Upgrading to a high efficiency air filter without any other considerations is costly.
@MRFoxMulder I agree. Most filters, especially highly Merv rated pleated filters, are SO efficient that the air is slowed down and wear and tear increases on the unit.
We use Merv rated polyester that captures particulate throughout the depth of the loft as opposed to just on the surface.
I want good filtration without excess restriction, the pleated filters in my unit are bowing when I remove them because they're pulling so hard. Fiberglass filters are useless, should I upsize the cold air return from 20 x 25, or have it modified to hold a thicker filter, say 2" to 4" ??
@jteamaz it does sound like the unit needs more area to breathe. The two and four inch filters will be stronger to resist the bowing you describe, but residential AC systems are designed to use 1" filters. Two cheaper suggestions than upsizing the return: change the filter monthly, sometimes dirt and grime increase resistance to airflow, and two try a polyester media form filter. Poly loads evenly and does not restrict airflow like traditional pleated filters do.
You're right - 0.5"wc is the "target" TESP - this will allow 400 cfm/ton give or take 10% - just right! BUT exactly HOW is the homeowner supposed to verify that the new "high performance" air filter won't reduce air flow and end up causing more problems than help?
Without a gauge, I suspect they should check the filter regularly and change it when they see visible dirt buildup. They should also follow all written instructions from the filter and HVAC equipment manufacturers.
ask the builder / do you say anything about how the pleated filter restrict air flow and that type filter will not work in all systems due to the airflow. I have seen these filters cause thee most problems in the a/c season due to the need for more airflow !!!!
That is not true. When clean, they do not cause a drop in static pressure that exceeds the normal limit of one-half inch. If they get clogged like any filter, then they can become problematic. All air filters must be kept clean.
In 5 years of cleaning electrostatics we've found the following - Electrostatic filters start up with about 25% higher resistance than standard pleated filters, but as they fill up they depth load while the pleated filter face loads. The result is, during the second half of the filter life, the electrostatic remains fairly constant in flow while the flow of the pleated is reduced significantly and quickly.
Electrostatic & pleated filters are a death sentence to system performance beause they increase static press. which reduces air flow. This can cause a furnace to overheat and the A/C to freeze up. Unlerss the system was designed them Contact a quailfied contractor who understands airflow performance and static pressures. Upgrading to a high efficiency air filter without any other considerations is costly.
MRFoxMulder 2 years ago
Correct. Dirty filters can dramatically increase static pressure.
AsktheBuilder 2 years ago
@MRFoxMulder I agree. Most filters, especially highly Merv rated pleated filters, are SO efficient that the air is slowed down and wear and tear increases on the unit.
We use Merv rated polyester that captures particulate throughout the depth of the loft as opposed to just on the surface.
LanceTruett 10 months ago
I want good filtration without excess restriction, the pleated filters in my unit are bowing when I remove them because they're pulling so hard. Fiberglass filters are useless, should I upsize the cold air return from 20 x 25, or have it modified to hold a thicker filter, say 2" to 4" ??
jteamaz 2 years ago
@jteamaz it does sound like the unit needs more area to breathe. The two and four inch filters will be stronger to resist the bowing you describe, but residential AC systems are designed to use 1" filters. Two cheaper suggestions than upsizing the return: change the filter monthly, sometimes dirt and grime increase resistance to airflow, and two try a polyester media form filter. Poly loads evenly and does not restrict airflow like traditional pleated filters do.
LanceTruett 10 months ago
what is the merve rating on the electrostatic filter?
aznpride1979 3 years ago
I believe it's the same as its coefficient of continuity.
AsktheBuilder 3 years ago
You're right - 0.5"wc is the "target" TESP - this will allow 400 cfm/ton give or take 10% - just right! BUT exactly HOW is the homeowner supposed to verify that the new "high performance" air filter won't reduce air flow and end up causing more problems than help?
dma3754 3 years ago
Without a gauge, I suspect they should check the filter regularly and change it when they see visible dirt buildup. They should also follow all written instructions from the filter and HVAC equipment manufacturers.
AsktheBuilder 3 years ago
ask the builder / do you say anything about how the pleated filter restrict air flow and that type filter will not work in all systems due to the airflow. I have seen these filters cause thee most problems in the a/c season due to the need for more airflow !!!!
loudew69 3 years ago
Yes, you have to be careful with all filters. Any can clog causing low air flow.
AsktheBuilder 3 years ago
no I mean that even before clogged they cause restriction
loudew69 3 years ago
I believe the standard is one-half inch of static pressure. If the clean filter creates less than that, it is okay.
AsktheBuilder 3 years ago
do not buy an electrostatic filter,they do not let enought airflow through.
LUGAM1 4 years ago
That is not true. When clean, they do not cause a drop in static pressure that exceeds the normal limit of one-half inch. If they get clogged like any filter, then they can become problematic. All air filters must be kept clean.
AsktheBuilder 4 years ago
In 5 years of cleaning electrostatics we've found the following - Electrostatic filters start up with about 25% higher resistance than standard pleated filters, but as they fill up they depth load while the pleated filter face loads. The result is, during the second half of the filter life, the electrostatic remains fairly constant in flow while the flow of the pleated is reduced significantly and quickly.
sonitx 2 years ago