Re: USA Today, on air cleaners and consumer reports findings

[Guest guest]

,

I have inspected thousands of heating and cooling units and ALL electronic,

electrostatic and washable filters for central heating and cooling systems

are nothing more than expensive gimmicks.(And yes, electronic cleaners can

certainly produce ozone).

The ONLY effective filter is pleated media filter that is changed at least

once or twice a year (and then thrown out, not turned around as I have some

frugal types do).

For folks with allergies, the filter should have a MERV rating of at least

8, but preferably 11.

There is no such thing as a HEPA filter for a homeowner furnace or AC unit.

(There are some companies that sell a very expensive bypass HEPA filter that

only filters about 10% of the air stream; this is about as effective as

breathing through a respirator with a big hole in the filter.)

You should throw away the heavy metal parts of your electronic filter and

just put the Honeywell media filter (four-inch, I believe) that they make to

fit inside the electronic filter case; just be sure the enclosure is

airtight.

Otherwise, the best filters are Aprilaire, Air Bear, Trion or Honeywell

pleated media filters. These filters require their own cases. For folks with

only one-inch filter holders, there are 3M filtrete pleated media filters.

Below is an article that I wrote for " Filter Forum "

C. May, M.A., CIAQP

May Indoor Air Investigations LLC

1522 Cambridge Street

Cambridge, MA 02139

617-354-1055

www.mayindoorair.com

www.myhouseiskillingme.com

>Thanks for the link -- looks interesting.

>I am sorry for not being more specific --

>I have an inline and wonder if this unit puts out dangerous ozone. I am

sure I can call the installer (bought by previous owner -- about 7 years

old) --but I can imagine what that installer / contractor will tell me.

>My unit is a Honeywell -- with two large " elements " and some crappy sort

>of prefilter (like something over a stove) and then the large electronic

>elements with a bunch of " IONIZER WIRE FOR 20 INCH FC37A " .

>Thanks....moldy Detroit air traffic controller

who <jeaninem660@...> wrote:

-this might be worth checking out.

http://www.allergybuyersclubshopping.com/ap-en-aircleaner.html

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Wake-Up Call

C. May, c 2001

In real estate jargon, advice to the buyer is summarized by the terse

phrase “location, location, location.” If there were comparable advice for

the building owner with air conditioning, it would be “filtration,

filtration, filtration.” Why is it then that when I ask owners about their

filter, the most common reply is “what filter?”

Few if any building owners (or even HVAC contractors for that matter!) are

aware of what filtration is for. The former have the notion that a filter

will create clean air for breathing; the majority of the latter, judging

from the installation and maintenance inadequacies I see, must feel that

filtration is nothing more than an annoyance. Filters are the victims,

always too big or too small, that get crushed or hung up on the

thoughtfully-placed, sheet-metal screws.

To understand the true significance of filtration, you must step back from

the equipment and consider three very simple principles: first, whenever and

wherever warm, humid air is cooled, water will form by condensation; second,

all indoor dust contains nutrients for bacteria, yeast and mold; and

finally, wherever dust is wet for more than a few hours, these

microorganisms will grow. (Has anyone ever turned on a cooling system that

didn’t stink initially?)

The relevance of these principles should be obvious to anyone, but for some

reason much of the HVAC industry, medical community and public have failed

to grasp their significance. Because virtually all filtration is inadequate,

nearly all air conditioning coils, condensate trays and fibrous liners are

soiled. Since all of these components are either physically wet or exposed

to high humidity, dust from almost every one of the hundreds of fan coil

units I have sampled was contaminated with active growth of microorganisms.

Is there any relevance to all of this? Right now the medical community and

the public are asleep, though some are awakening from their moldy

nightmares. When more people realize what has been going on, they are going

to look for someone to blame. Air conveyance systems, particularly if they

also serve as sources of heat, can be an enormous source of bioaerosol-

airborne particulates resulting from the growth of microorganisms thriving

in the system. The bioaerosol from HVAC systems can cause allergy, asthma,

chronic cough and hypersensitivity pneumonitis (HP) to name a few. HVAC

equipment with microbial contamination - rather than “tight buildings” or

inadequate ventilation - is the cause for the majority of IAQ problems in

“sick buildings.”

Proper maintenance (of a well-designed system) is the only way to avoid

creating conditions that can lead to these illnesses; optimizing filtration

is the building owner’s most important preventative tool! There should

never be nutrients (dust) on an air conditioning coil, in a condensate pan

or on the fibrous lining material near the coil. The only way to keep these

surfaces clean is with at least 90% arrestance (or MERV 6) efficient

filtration such as that provided by typical media filters. Filter enclosures

must be airtight to the exterior and filters installed so that no air

bypasses them.

We must stop kidding ourselves and the public about filtration. How can a

typical fiberglass filter that I can clearly see through adequately collect

microscopic particulates? These filters are actually worse than useless

because not only do they provide totally inadequate filtration for any

cooling system, they also provide the building owner with a false sense of

confidence. In any given system, the most efficient filter possible should

be used. If more powerful blowers are needed, so be it. Up to now,

energy-cost savings have driven HVAC design. It’s time to realize that the

increased costs associated with providing and maintaining good IAQ can no

longer be avoided.

From an IAQ perspective, the HVAC industry has a long way to go before

newly installed equipment will provide adequate protection; and an even

longer road to travel before making the existing installations safe. No

gimmicks, such as UV irradiation, bypass HEPA filters (for a small fraction

of the air stream) or chemically treated filters will ever substitute for

the real thing: clean fan coil surfaces free of growing microbes. This

condition can only be provided by efficient filtration and intelligent

filter maintenance.

Nearly every cubic foot of air in a typical building has been blown over

some type of coil or coarsely-lined surface. Some of that air will end up in

an occupant’s lungs and therefore the health of every individual who

breathes indoors is the responsibility of building designers, engineers and

maintenance personnel. Let’s hope that the HVAC community wakes up to this

realization before the legal community does!

May is author of “My House is Killing Me!:The Home Guide for

Families with Allergies and Asthma” (2001), “The Mold Survival Guide: For

Your Home and for Your Health (2004) and “My Office is Killing Me! The Sick

Building Survival Guide (2006), all published by the s Hopkins

University Press, Baltimore, MD. obtained an M.A. in organic

chemistry from Harvard and stayed in Cambridge to found May Indoor Air

Investigations LLC., a company that investigates mold, odor and moisture

problems building.