expired Posted by Lokotron21 ā¢ Sep 29, 2024
Sep 29, 2024 6:23 PM
Item 1 of 1
expired Posted by Lokotron21 ā¢ Sep 29, 2024
Sep 29, 2024 6:23 PM
6-Pack Frigidaire PureAir MERV 8 Allergen Pleated AC Furnace Air Filters
w/ S&S + Free S&H$33
$50
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$25.92 for a 6 pack everyday
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51 Comments
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https://www.youtube.com/watch?v=RkjRKIR
Take out of it what you will, but this lower MERV rating is better for your furnace seems to be a bit of a myth and depends on the quality of your filter...
However, for unknown brands/models, then I do agree with the "GENERAL" advice that a Merv 8 Filter is probably better than some unknown brand of Merv 11 or higher... it's generally safer.
However, stronger filtration AND better airflow?... yes please!
For filters of the same thickness, a higher MERV rating makes the filter more restrictive, which in turn increases the static pressure. This is universal, completely independent of any other aspect of your system. There are variables that can affect the metric by which return size/number and air returns are determined - and if, say, you're retrofitting an old system for which the ductwork is now under- or oversized, you may have some flexibility - but assuming your system was designed by a competent HVAC engineer, what they install is what you should use. And what they usually install is MERV 8.
The issue of static pressure is generally related to the blower. The blower has an "ideal" range of operation; the maximum MERV rating of the filter to be used is whatever highest level of filtration that allows it operate within spec (ie. without stressing or straining the motor/system). Going above that is bad. You noted this with your reference to MTBF. Something important to note: when HVAC systems are being designed, they are done so without the filter in mind. This will come up later.
Going with a filter with too low a MERV rating can be bad, too, and I think that's what you're disagreeing with me about? The HVAC filter has exactly zero to do with the indoor air quality and exactly everything to do with protecting the coils from accumulating crap. A lower MERV filter will (surprise!) filter out less stuff. That "stuff" can then end up accumulating on the coils. You absolutely want the highest MERV filter you can use that doesn't stress (or at least minimizes stress on) the system.
For a system using 1" pleated filters, MERV 8 is the "standard" because it is 90%-ish efficient down to particles around 3 microns in size, which covers the majority (not all!) of "household dust" from making its way to the coil. The efficiency bit is key here. Because the HVAC system is designed without the filter in mind, you want to minimize the impact on the system. MERV 8 being 90% efficient means you have very little impact on the airflow, while maximizing filtration of "stuff" that has the biggest negative impact on the coils. For 1" filters, MERV 8 is simply the best "bang for your buck".
Unless the system was specifically designed for it - or your (competent) HVAC installer recommends it - going higher or lower than MERV 8 on a 1" filter is going to have a net negative effect on your system.
https://www.youtube.com/watch?v=RkjRKIR
Take out of it what you will, but this lower MERV rating is better for your furnace seems to be a bit of a myth and depends on the quality of your filter...
However, for unknown brands/models, then I do agree with the "GENERAL" advice that a Merv 8 Filter is probably better than some unknown brand of Merv 11 or higher... it's generally safer.
However, stronger filtration AND better airflow?... yes please!
Did anyone else have different takeaways?