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What are the Consequences of Filter Bypass?
Filter Bypass:
Filter bypass is defined as “airflow around a filter or through an
unintended path”. Many filter frames, constructed of hard metals, have
imperfections in the filter track. Filters frames, constructed of
cardboard, that are not self-sealing, are too rigid to conform to the
contour of the filter frame, leaving gaps for air to bypass the
filtering process. Gaps the size of a human hair, approximately seventy
microns in diameter, are large enough to allow all particles of concern
to escape the filtration process and re-enter the inhabited spaces.
Therefore, by simply improving filter efficiency without addressing
filter bypass, you provide little if any benefit.
Air
that bypasses the filter can carry dust and other particulate matter
directly into the evaporator coil and ventilation system. Dust can
provide a nutrient base on which fungi can grow.
Biological Contaminants:
 “Contaminated
central air handling systems can become breeding grounds for mold,
mildew and other biological contaminants and can then distribute these
contaminants throughout the occupied spaces.” (EPA Indoor
Air-publications – “The Inside Story: A Guide to Indoor Air Quality).
Increased
Energy Costs:
“HVAC systems evaporator coils and drip pans are a breeding ground for
bacteria, mold, algae and other fungi. A .05 inch accumulation of this
sticky dirty substance can cut efficiency 32% - raising your electric
bill for that unit at least one-third.” (HVAC Magazine Online –
Clean A/C Saves Money)
Dirty
Coils:
“A
dirty blower or air conditioning coil inside an air handler can increase
operation
costs by restricting air flow and heat transfer and can also cause
premature motor wear. In addition, restricted airflow can lead to
reduced heat transfer at the furnace heat exchanger.” (Home Energy
Magazine Online – July/August 1996).
Coil Fouling:
“Particle deposition of indoor dusts and other particulate matter on
evaporator heat exchangers, increases system pressure drop and
correspondingly, decreases system airflow and air conditioner
performance. An accumulation of 140 (+/ – 10) grams of particulate
matter deposited on evaporator coils can double pressure drop. For this
level of pressure drop, in a typical residential system, the pressure
drop at the fouled flow is increased about 40%; the airflow is reduced
by 5 to 10%, and the efficiency and capacity of the air conditioner
decrease by 2 to 4%.” (California Institute for Energy Efficiency -
Dirty Air Conditioners: Energy Implications of Coil Fouling).
Lack of MERV Integrity:
“ASHRAE Standard 52.2 testing as well as most other filter test
methodologies, are tests of the filter media, rather than the installed
filter system. When applied to real systems, filter test results
implicitly assume that no bypass exists around filters. Examination of
most residential and commercial HVAC systems suggests that this is not a
good assumption: both small and large gaps are common.”
“An
HVAC design that employs high efficiency filters to prevent health
problems associated with indoor fine particles may fail to perform as
intended due to filter bypass.” Mathew Ward – Modeling Filter
Bypass: Impact on Filter Efficiency”.
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Facts
About Filters
The air filter you use in your central
heating/air-conditioning system has
two important functions:
1). To remove from an air-stream the greatest number of
particles whose size is of most concern and
2). Provide adequate airflow necessary to maintain satisfactory operation of
your heating/air-conditioning unit.
Some air filters that are efficient at
capturing particles fail to provide adequate airflow.
Restriction of airflow can result in:
1). Increased energy consumption.
2). Failure to pull particles to the air filter resulting in increased dust,
etc. in the environment.
3). Irregular uneven temperatures throughout the home.
4). Decreased effective lifetime of the heating and cooling unit.
5). Increased possibility of compressor and blower motor burnout.
6). Increased possibility of high pressure overloads and frozen coils.
Some air filters provide excellent
airflow but fail to capture an adequate amount of particles of most
concern.
Inadequate filtration can result in:
1). Failure to provide the degree of cleanliness required for normal
occupancy and space usage.
2). Increased maintenance of your heating/air-conditioning system due to
build up of particles on coils, fan motor and duct system.
3). Increased possibility of mold. mildew and other microbial growth in the
ventilation system.
Proper maintenance a requirement.
Whether you purchase a filter that provides excellent airflow
or a filter with excellent filtration capabilities, proper maintenance is a
necessity. As particles accumulate on the face of the filter restriction of
airflow may occur. When an air filter reaches its capacity to hold
particles it has captured, the particles are pulled through the filter and
re-enter the air stream and ultimately the environment you live in.
Studies show
that a well maintained filter can reduce energy consumption, in the
operation of your heating/air-conditioning system, by up to 4%.
Cleaning/replacing dirty filters on a timely basis can save hundreds of
dollars over the years.
Never be without a clean filter again!
With the purchase of any
A+2000 air filter you
can, upon request, receive a friendly reminder to change/clean your
filter on a 30, 60, 90 or 180 day schedule.
How To Measure
Custom Size Filters
| Filtration
Manufacturing, Inc. is committed to providing quality
solutions for all of your air filtration needs. Our
company can custom make any and all types of air
filters, both standard and custom. Send Filtration
Manufacturing your technical requirements and one of our
trained sales representatives will contact you.
customerservice@filtrationmanufacturing.com
Please measure in fractions
when ordering (i.e., 1/4", 3/8", 7/16", etc.) : |
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