A deep filter unit can clean everything out of the air you can see,
but most of the allergens are a little smaller and need an HEPA filter.
It is after the 99.99% that these allergens usually lurk.  No filter
will take out odors or gases, but some can be captured by charcoal or
special earths.  If someone is saying your room is dusty and you have
no health problem with allergens, just dust and vacuum!

The "electronic" air filters are generally composed of pins or wires
which ionize what is passing through the forced-air system and the air
flows through but the ionized particles are captured by plates.  This
is done by applying a high DC voltage to the "grid" and to the
"plates".  This is just electricity, but since this generates a flow
of electrons, it is called "electronic"; it isn't necessary to have any
transistors, vacuum tubes or such circuitry involved.  You have to run
the blower pretty much all the time to make this effective, which can
be a considerable expense.

The air, composed of N2 and O2, may be partly ionized but it is mostly
the particles you are interested in here.  If oxygen or nitrogen are
ionized, it makes them more chemically active.  Ozone is ionized
oxygen.  It has an acrid odor and, like many acrid gases, it is
going to oxidize whatever it can react with which is usually organic
materials like rubber.  Your auto tires, wipers, window gaskets and
upholstery will get surface deterioration from this faster in smoggy
areas, and your pneumatics with rubberized cloth will have a short life.

I would suggest that you not use the ionizer system and ask the dealer
to measure the ozone level in the air before and after installing the
system so you can be sure your pneumatics will be safe and your drapes
won't shred themselves.

As an engineering professional, I like the idea of having electricity
do my dusting and wall cleaning, and have always put in the best air
cleaners both in industry and at home.  After having half a dozen
"electronic" air cleaners, and having studied the work of Cottrell
and his successors, I thought I had seen most of the methods used in
the large industrial units and had seen those methods applied much more
expensively in small home units until I saw the Trane 'Clean Effects'
unit.

This one has the greatest ratings for the smallest particles in the
allergen range.  Being bothered by allergies, I shelled out a kilobuck
for the privilege of having one of these marvels stuffed into my ducts.

It has an array of pins sticking out downstream, then a plate with
large holes in it just past the end of the pins.  The high voltage
is supposed to generate a corona (purple glowing ionized air) between
the pins and the plate.  All the air and dust pass through this and,
by traditional logic, would be charged by the pins and accumulate on
the plate with large holes, but there is another very thick grid placed
just after, also apparently with a charge on it, which is supposed to
collect the material energized by the corona.

The plates in the old systems would collect a furry mat of dust and
sticky residue from cooking, cats and cigarettes.  Monthly, I would
remove the plate grid, spray lightly with 409 cleaner, and hose them
off with hot water and get quite a flood of brown ink to run down
the drain.

Now the Clean Effects unit is merely supposed to be vacuumed out
since the fancy stack of square soda straws through which the air
passes is not friendly with detergents and water.  I vacuum with the
Rainbow water wall unit or the Dyson and in the Dyson I see a teaspoon
of fine dust and in the Rainbow only a vaguely murky tub of water.

I wonder what has happened to all the fuzzy stuff and brown goo
I used to get from the old-fashioned units from Honeywell, Phillips,
Carrier, etc.  Was it all destroyed to the nuclear level?  Was the
thing turned on at all?  Is this a case of the King's New Clothes?

Unfortunately, after five service calls from ever increasing
echelons of HVAC specialists, and after a year of telephone calls,
they are unable to tell me exactly what I should be seeing when
I vacuum the collector and the furniture is covered with dust.

They insist that the thing has to be working because their laboratory
tests are great and they couldn't get away with selling something which
didn't to the job.  One day, perhaps I will get a satisfactory answer.

Karl Petersen
Washington, Illinois