Types of air conditioning filters to select from; plus proper filter area sizing

I might use a 4" Merv 7 Filter as it has a very low pressure drop close to the fiber-glass filter click link below.
If you use Fiberglass media Filters; start at under 300-fpm velocity to reduce debris going through them!
Comparative Tests concerning Pressure Drops of HVAC Filters - some browser's may not show the Criteria!
At 300-fpm, the 4" deep Merv 7 has a pressure drop close to the 1" fiber glass filter; in Test, all filter areas were 24X24.
Good performance data on Merv 7 filters - pdf download
Return Air Filter Tutorial

A New Brand of Comfort and Efficiency Excellent linked articles by 'Doc'
Jan 2, 2013 1:33 PM, By Rob 'Doc' Falke

Please Respond on my Blog; let me know if you can't post: Ballpark Checking A/C Performance

  Pros Cons Characteristics Filter Specific Notes
Fiberglass Panel Filters 
fiberglass panel filters
  • Inexpensive
  • Low air flow restriction
  • Full depth loading
  • Panel filter
  • Available at most hardware stores
  • Not efficient
  • Allow most dust to pass through
  • Disposable
  • 1 and 2 inch thickness
  • Panel filters
  • Fiberglass panel filters are the worst possible air filter you could use in your heating or air conditioning system and I would never recommend using them
Media Air Filter Pads 
media air filter padsmedia air filter pads
  • Low air flow restriction
  • Don’t have to be changed as often as pleated filters
  • Great for those who sometimes  forget to change or clean their filters
  • Not face loading (increases dust loading capacity)
  • Can be messy to change because they have to be removed from a frame which can release dust back into the air
  • Not as efficient as high end pleated air filters
  • Disposable
  • 1/2, 1 and 2 inch thickness
  • Available in pre-cut pads or rolls that can be cut to size
  • Require metal filter frame to mount them in 
  • Very high dust loading capacity (full depth of media) because of multi-denier design characteristics
  • Good for those who require more flexibility with filter change schedules
  • Carbon filter pads can be installed with these media pads for odor control
  • Permanent frame with disposable pads
  • Usually made with polyester fibers bonded together
  • Often available with dry tack or other coating to increase efficiency
  • Some designs make their filter media more course on the air leaving side to improve filter performance
Electrostatic Air Filters 

True electrostatic filters don’t require electricity.


electrostatic air filter cutawayboair electrostatic furnace filteraluminum frame electrostatic filter
  • Permanent and washable
  • Moderate air flow restriction
  • Most last for years
  • Many have lifetime warranties
  • No face loading (increases dust loading capacity)
  • No electricity required
  • No ozone is produced with these filters
  • One time purchase cost – saves you money
  • Many different designs and not all are good quality
  • If not properly maintained they will restrict air flow
  • Regular cleaning is required
  • Don’t require electricity
  • Washable
  • Should be cleaned monthly
  • 1/2 and 1 inch thick
  • Custom sizes often available
  • aluminum or flex frames available
  • Panel design
  • Maintenance is very important with these filters
  • Green? They don’t add to landfill usage compared to disposables because they last many years
  • Some brands use anti microbial protection which inhibits the growth of mold and mildew on the filter material
  • Direct replacement for disposable panel filters
  • Combines 3 to 5 layers of material to obtain desired characteristics
  • Electrostatic air filters don’t produce ozone
Pleated Air Filters 
pleated furnace filter
  • Available in wide range of MERV ratings from 5 to 12
  • Low to moderate air flow restriction
  • Panel filter
  • Can be found at most hardware stores
  • If not changed when needed they will impact air flow
  • Face loading (pleated design helps increase dust loading capacity)
  • Disposable
  • Available in 1 to 6 inches thick
  • Available in custom sizes
  • Panel filter
  • The more efficientpleated air filters are great for allergy sufferers
  • Most common type of furnace filter and air conditioner filter available
  • Some brands are enhanced with electrostatic characteristics
  • Variety of media types - cotton, synthetic blends and polyester
  • Some are made with carbon (charcoal) impinged material to help control odor
  • Many manufacturers such as Trion, Honeywell, Nordic Filtrete, Air Bear and many others
  • Made with pleated design to increase surface area and dust loading capacity, this increases usable life
Hepa Air Filters 
hepa furnace filter

What does HEPA stand for? 
High Efficiency Particulate Arrestance

  • Panel filter
  • Very efficient filters
  • One of the most efficient filters available for residential use
  • Can have a negative impact on air flow, especially if not maintained properly
  • Face loading (pleated design helps increase dust loading capacity)
  • 1, 2 and 4 inch thickness
  • Pleated design
  • Good choice for those who have allergies
  • Hepa filters are often available in bypass systems
  • Similar design as standard pleated filters but more pleats per inch and different filter material
  • Some can be cleaned and reused several times
  • These filters are commonly used in vacuum cleaners, air exchangers (HRV) and air purifiers
Electronic Air Cleaners 

I consider any type of air filter that uses electricity to be an electronic air filter.

  • Very efficient but not with larger dust particles
  • Virtually no restriction to air flow
  • Excellent for use in combination with panel and other media air filters
  • Lasts for many years
  • Requires 120 or 240 volt power supply
  • Larger dust particles pass through this air cleaner
  • Duct system must be modified to install this equipment (not difficult for handyman)
  • Expensive initial investment compared to media type air filters
  • Can create ozone
  • Charges dust particles as they pass through and they are attracted to collection plates
  • Requires regular maintenance to maintain efficient operation
  • There are two different designs of electronic air filters to choose from 1) Uses electronic cells with collection plates and 2) Panel type electronic filters that incorporate filter media in the design
UV Air Cleaners
  • No restriction to air flow
  • Excellent for use in combination with media air filters such as pleated and electrostatic
  • Can be easily installed by a handyman
  • Easy maintenance – change lamp once per year
  • Requires electricity to operate
  • Create ozone – some are worse than others
  • Kills mold spores, viruses, bacteria, and many allergens
  • Some lamps produce UV-V light while others produce UV-C light
  • The UV-V type ultraviolet lamp  produces more ozone
  • Avoid looking directly at the light because it could damage your eyes
  • Damages plastic drain pans and rubber components so must be installed properly

The Bryant 3 filter tiered cabinet, each filter is positioned to filter one-third of the Return Air:

Three Tiered Filter Cabinet
In some situations it could be a good application selection.


Filter Sizing Methods Blocking off areas of filter for testing results - see below info
Source http://dnr.louisiana.gov/assets/TAD/education/ECEP/hvac/g/g.htm

Well, after looking over those figures; they are wrong for the physical size of the filter.
For fiberglass panel filters, about 69% is open-air-area (Ak) sq.,ft., area. (Using Hart & Cooley Engineering Data, with a RA grille.)
2000-cfm/300-fpm = 6.666-sf *144 = 960-Free-Air-Area or (Ak);
the "Physical Area" to get that free-area is 960
-sq.ins., is nearly 1400-sq.ins of Physical Area.
Use two filter areas...

Always use the above equation, many other methods won't always provide correct results.

Different filter types have different
open-air-area (Ak) sq,.ft., areas; so U need to know the Ak or, test for 300-fpm through the filter with an anemometer.

  In numerous situations, the Bryant 3 filter cabinet could be a good option!
Link to cabinet filter system is above.
================================================================================================
MY EFFICIENCY HVAC A/C OPTIMIZATION PAGE LINKS:
  • OIL HEATING AIRFLOW TEST  Using Thermometers

  • Follow me on Twitter All about Reducing Energy Costs - New

  •      HVAC TALK HVAC Talk Community

    HVACR TALK FORUM  - Residential Problems - NEW

    Refrigeration Engineer Forums - AIR CONDITIONING
    HOME INSPECTIONS Learn about home inspections also HVAC inspections
    DIY Do It Yourself Forum" "Do It Yourself" TV- I Am "HVAC RETIRED"
    MY HVAC BLOG - YOUR QUESTIONS & COMMENTS WELCOME *Use for listing test data required for effective trouble-shooting!
    GARDEN WEB - Heating & Air Conditioning Forum 
    HVAC Discussions  Mike Holmes HVAC Forum - New


    WISDOM PRINCIPLED EMPOWERMENT COMMUNICATIONS 

    MY GLOBAL ECONOMIC Policy PEOPLE EMPOWERMENT PAGES

    Author of - WISDOM PRINCIPLED EMPOWERMENT COMMUNICATIONS 
    -----------------------------------------------------------------------------------------------
    Darrell Udelhoven - HVAC RETIRED - udarrell
    Empowerment Communications
    People Empowerment Broadcasting

    Darrell Udelhoven - (U-dl-hoven)
    udarrell.com

    Copyright ©2011 All rights reserved
    udarrell, Darrell,  Bloomington, Lancaster, Grant County, Wisconsin


    Empowerment Communications
     
    Covering The Real Political Issues
     
    Posted: 07/14/11
    ; Updated: 12/18/12