Air Purifiers, Cleaners & Ionizers
Reviews, Comparisons & Buying Guide
HEPA Filter: What It Is, What It Does and What It Doesn't Do
HEPA filters are one of
the most widely-known methods of air cleaning. In fact, when most
people think of an air cleaner, they think of a HEPA filter. However,
HEPA filters - and ALL filters, for that matter - have limitations
that must be taken into consideration when choosing an air cleaning
unit for your home or office.
Because filtration systems (HEPA and
other filters) dilute contaminated air with cleaner air, their effectiveness
depends largely upon how much filtered air they deliver over a given
period into a specified space. Consequently, most filtration-type
air cleaners (they are NOT air purifiers because the cannot
purify the ambient air of very small contaminants like viruses!)
have large, often loud fans because they only clean the air they
can actually filter through them.
The History of HEPA Filters
is an acronym for High Efficiency Particulate Air Filter, which was
used in U.S. military specifications beginning around World War II.
The precise definition of a HEPA varies somewhat from country to
country and from specifier to specifier with respect to the efficiency
for a particular test method.
A conventional HEPA filter consists
of a continuous sheet of a special paper-like, glass-fiber filter
medium which is pleated into a "V" configuration
with corrugated aluminum separators between the pleats. This forms
the filter element, which is then bonded into a rigid frame using
a special polyurethane compound. Standard filters are produced in
a range of face dimensions and in two standard depths of nominally
150 mm and 300 mm.
Drawbacks to HEPA Filters
HEPA filters cannot be
cleaned to remove particulate and dust loading and must be replaced
as a complete assembly, often at significant yearly cost. As the
particle load increases, so will the resistance to flow and hence
the pressure drop across the filter. In some applications, uneven
filter loading will cause non-uniform airflow through the filter
and decreased effectiveness. Additionally, inexpensive HEPA
filter systems often do not seal the filter chamber properly, so contaminated
air simply passes through the holes and back into the ambient air.
Some manufacturers will void your warranty on filtration
systems if you do not replace the filter according to a very specific
schedule, and most will not cover damage caused to the unit by clogged
filters, which can cause the fan motor to burn up.
Even the larger HEPA air filters cover only a single room,
or at most a small apartment. This is because in order for the air
to be cleaned, it must pass through the filter. As a result, they
can only clean the air that is nearby. While some filtration systems
do incorporate flimsy charcoal or other filtration media that can
absorb odors, they tend to have little effect on odors and virtually
none on bacteria, viruses, germs and fungi like mold.
Disadvantages to Filtration Systems
HEPA filters are extremely
fragile and can easily be damaged during installation, cleaning,
and even when the unit is moved. HEPA filters should be tested
at least annually. Replacement filters can cost as much as $200
(average is $75 - $150). Many air cleaner brands using HEPA filters
now require that you change the filters at least once
and often twice a year in order to validate the unit's warranty.
HEPA units are usually loud - often sounding
like a window air conditioner. Some even sound like small lawnmowers!
HEPA filters are costly to operate - from $100 - $300 annually
in energy usage. Filter-less air purification devices cost, on average,
approximately $30 to 50 per year to operate.
HEPA filters may cost
less "up front," but actually purify less air, less effectively.
Cost per square foot of filtration with a HEPA unit ranges from
.35 cents to as much as $1.10 (or more); filter-less air purifiers
units average .18 - .25 cents per square foot (not including electricity
A key point to consider
is that HEPA filters are simply that -- filters -- and are designed
ONLY to FILTER larger (0.3 and above) micron-sized particulates from
the air, and they can do it quickly. It is true that they can remove
mold spores and bacteria from
the air, but unless the filter is treated with an anti-microbial
substance -- which is often, in itself, a contaminant --
still-living microbials continue to grow and multiply on the HEPA
filter. And when you pull out the filter to change it, guess where
Some air cleaner models offer optional filters for smoke and odors,
but these simply trap chemicals and odor vapors in activated charcoal
or carbon, and are not very effective unless
they have a sizeable carbon, like in the Airpura models. However,
it is nearly impossible to know at what point the carbon becomes saturated
and can no longer absorber chemicals and odors.
By contrast, filter-less air purification devices based on Germicidal
UV technology, like the Air Oasis, oxidize odors and vapors, removing
them permanently, and they are effective on even microscopic particulates,
bacteria, and viruses as small as .001 microns (many viruses, herbicides
and pesticides are that small).
HEPA filter effectiveness significantly
diminishes as the particles become smaller. As particles become very
small, they cease to behave so much like particles as they do gas phase
molecules. It is difficult to tell whether such small particles are
actually suspended in air (particles) or diffused throughout it (gas
or vapor). The bottom boundary where particles act as true particles
is about 0.01 micron. The normal theory of separation does not apply
to particles below this size and removing them from air requires techniques
reserved for gaseous materials, like the Air Oasis technology. Particles
above 0.01 micron are usually considered to be filterable. Particulates
smaller than 0.01 include pesticides, herbicides, some atmospheric
dust and nearly all viruses. Plus HEPA filters do not remove gases
or VOCs (volatile organic chemical) off gassed from most new carpeting,
building materials, furniture, etc.
To see the actual micron size
of common particles
found in your home Click
We offer two brands that include HEPA filtration in combination with
other technologies. Surround models are great for residential applications,
while Airpura are excellent for larger spaces and commercial applications:
Airpura Commercial HEPA and Carbon Air Cleaners
is a completely new air cleaner with all the design improvements lacking in
other similar technology systems. Airpura design principles include a simplified
unobstructed air flow for quieter more efficient performance and reduced noise.
The prefilter can be vacuumed through the mesh for easy monthly maintenance,
then replaced every 12 months. Two special microbial (bacteria and viruses)
suppressing filters help to protect the hefty 18 or 26 pound carbon bed. Felt
gaskets are used to seal the filter chamber, eliminating rubber seal off
gassing. The metal capped HEPA filter removes the possibility of any
plastic vapors from non-metal caps.
Airpura uses a powerful, variable speed integrated fan/motor, letting you
choose the rate you clean your air from super quiet to premium power filtering
with 560 CFM capacity. With Airpura's effective pressure sealed filter chamber,
all air is filtered; NO particles or gases escape. Other systems allow
leakage and can't achieve the claimed 99.97% HEPA efficiency. And, Airpura
offers the cleanest air, using superior quality true HEPA and activated carbon
(special carbon blends are available) with optional UV sterilization to deliver
truly clean air for home, office and industrial applications. Airpura is available
models and three colors: Cream, white and black. more
Surround Air Multi-Tech Ionizers
ions clean the air by magnetically attracting to pollutants until these newly-formed
larger particles become too heavy to remain in the air you breathe and they
fall to the ground. Surround Air Ionizers continually produce negative ions,
without creating the "black-wall" effect of older ionization technologies,
so even if one of these fallen particles is kicked up into the air, it is quickly
removed again. The most important thing, though, is that they are taken out
of the air, preventing you from inhaling them into your lungs, which is how
they cause problems.
Since certain technologies are much better than others at
removing different types of air pollutants, all Surround Ionizers are multi-technology.
All models include ionization, a prefilter, a HEPA and Carbon Filter and UV
lamp, plus some models include a TiO2 filter or an optional ozone sanitizer.
And, the Intelli-Pro includes electronic sensors. With Surround, you get the
best of the most advanced air purification technologies on the market, all
rolled into one air purifier. The best part is that Surround Multi-tech ionizers
and replacement filters are affordable
for every budget. more info
Venmar Air and Humidity Ventilation
For the past two decades mounting evidence suggests that dependence on the
natural exchange of air between the indoors and outdoors through air infiltration
and exfiltration may not be sufficient for good moisture control and indoor
air quality. It also has become increasingly obvious that traditional ventilation
methods, like opening a window or use of a common bath fan, are not providing
adequate ventilation. A properly designed and installed ventilation system
is the key to positive moisture control and will help ensure a healthy indoor
environment for the occupant.
The solution is heat recovery ventilators (HRV) and energy recovery ventilators
(ERV). These mechanical ventilation systems use fans to maintain a low-velocity
flow of fresh outdoor air into the house (incoming air stream) while exhausting
out an equal amount of stale indoor air (exhaust air stream). Fresh air is
supplied to all levels of the house while stale air is removed from areas with
high levels of pollutants and moisture. more
Filter-less Ways to Remove Particulate
Filter-less Air Purification devices rely on special UV technology
that creates unique oxidizers -- for instance, Hydroxyl ions, hydro
peroxides, super oxide ions, passive negative ions hydroxides and ozonide
ions -- that seek out and destroy odors and contaminants throughout
your home. They can effectively remove the particulate like dust, pollen
and dander, although not at quickly as can be removed by a large,
noisy fan-based filter. However, they are significantly quieter and have
very low maintenance (replace the cell once every three years).
Oasis Induct works with a HVAC system ductwork to provide
whole-home purification. (AC systems also remove beneficial negative
ions from the air; Air Oasis units replace them, giving you better
sleep quality, enhanced mood and superior air purification).
With oxidation air purification technology, all you ever replace
is the lamp once a year with most models on the market, or once
every 3 years with Air
Oasis Air Purifiers.
Air Oasis Breakthrough G3 UV Air Purification Technology!
air purifier on the market can compete in effectiveness, energy efficiency,
adaptability and quiet operation, when compared to the Air Oasis G3 patent-pending
Nano Nickel HCT photocatalytic oxidation technology. Other oxidation brands
use only titanium dioxide (TiO2) as a catalyst, the cheapest, most available
catalyst metal on the market, whereas Air Oasis contains five rare catalyst
metals and nano size metals to increase the kinetic rate of reaction.
Unlike HEPA filters that only remove some particulate and carbon filters that
only remove chemicals, VOCs and odors, Air Oasis technology is proven
effective against MRSA, bacteria, molds, VOCs, chemicals, gases, odors, pollen,
dander and more. Extensive testing conducted by West Texas A&M University
at BSA Hospital confirm that Air Oasis not only purifies your air, but sanitizes
surfaces, too. Additionally,
Air Oasis Air Purifers are made in the USA, using brushed aluminum casings
and UV lamps that utilize a proprietary long life
coating, allowing them to outlast any UV lamp on the market. Read
More about Air Oasis G3 Air Purifiers
Find the Right Air Purifier for
Your Unique Problem
It's no mystery that the air inside our homes, offices and nearly every building
we enter is contaminated with
toxic air pollution problems. But wading through the plethora of air purification
technologies and models to make our living and working space free of pollution
can be a daunting task, especially with the misinformation presented by so
many salespeople and web sites. There are many different air purification technologies
and air filters on the market, but no one air purifier technology can solve
every air pollution problem, which is why we carry different brands. For help
determining which air purifier is right for you, click on one of the below
links or call us toll free at 866-875-4386 (US and Canada).