Re: Re: Filtration

[Guest guest]

You're right, Gil. Most HVAC filters are placed before the A/C coil

and drip pan. Which means the mold, bacteria and other

emanations have to circulate through the house and back into the

return vents before it can be filtered.

Barb, I share your frustration. Few things are designed with

people in mind, only the convenience and low cost to someone

else. I remember when the desks in schools were in fixed rows

bolted to the floor. Why? It was easier for the janitor to sweep.

Carl Grimes

Healthy Habitats LLC

-----

Carl made some good points about filters. But there is another

consideration. Whole house filtration is handled by the filter on the

furnace/air conditioner. This filter is almost always placed before the air

handler, designed more to protect the air handler than the building

occupants. If designed, installed, and maintained right, it does both jobs

well. However, if inadequate filters have been used, there is almost

certainly a microbe garden on the AC coils and drain pan, or the furnace

humidifier, or on interior insulation of the air handler chamber.

Allergenic/toxic bioaerosols from this source can be blown into the air

stream every time the fan comes on. The system supposedly designed to

protect your comfort and health can become your worst problem.

When I was still working, I developed major coughing problems related

to the workplace HVAC. A brand new HVAC system was installed, and I

developed problems again when the brand new system was only three

months old. I could not convince my employer that the many openings of

this large system to measure and balance air flow had allowed in enough

contaminant to cause a problem, and they wouldn't get it cleaned. But

claiming rights under the ADA, I convinced them to install filtration in

the air duct to my work site. It worked quite well, allowing my to

continue working a few more years until early retirement. As Carl stated,

a filter only helps if it filters the air coming from the problem source.

Gil

Filtration - Was: Culturable mold indoor~association w/moisture-rel

Posted by: " Carl E. Grimes " grimes@... grimeshh

Date: Mon Jul 12, 2010 7:33 pm ((PDT))

Barb and others,

Yes, but that is only one reason HEPA and high MERV rated

filters cannot be depended on to solve contamination problems.

Not only for the ultrafine particles but even the ones they are

designed to capture.

1. No filter removes the contamination from its location. It can

only remove that portion of the contamination which is in the air. If

there is mold growing in the crawlspace or attic, for example, no

air filter in the bedroom can clean up the crawlspace or attic.

It's like having a cigar smoker in your house and trying to remove

all the smoke with an air filter. Can't be done because it just

keeps coming and coming. Like Timex watches which just keep

on ticking. Or the Energizer Bunny which keeps on going. Or

Doritos. We'll make more.

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[Guest guest]

my new place has radiant heat, are there any issues I should be aware of

with radiant heat?

thanks, sue

>

>Carl made some good points about filters. But there is another

>consideration. Whole house filtration is handled by the filter on the

>furnace/air conditioner. This filter is almost always placed before the

>air handler, designed more to protect the air handler than the building

>occupants. If designed, installed, and maintained right, it does both

>jobs well. However, if inadequate filters have been used, there is