From: "Ted B." 
Newsgroups: misc.consumers misc.consumers.house
Subject: Re: Are allergen filters any good?
Date: Mon, 25 Jul 2005 10:19:11 -0400


"John Graeme"  wrote in message 
news:1122297973.810003.162430@o13g2000cwo.googlegroups.com...
> Has anyone had any experience using a high-efficiency filter like the
> 3M allergen filters in their furnace/central AC?  Is there any
> significant improvement in dust or allergens, and can they cause any
> problems with the unit by restricting the flow of air?
>
> Thanks in advance.
>

I think I can answer this one.  I've got one in my natural gas forced-air 
furnace.  As someone who suffers from multiple allergies, I don't think the 
allergen filter makes any difference.  No, I have no data or anything to 
support that assumption.  But I do believe it's valid.  Here's why:

I also have used a Honeywell brand HEPA air purifier for years in my 
bedroom.  That DOES make a difference.  As long as that is running, I have 
no problem with allergies, as long as I stay in the bedroom.  But I have 
noticed that if the HEPA air purifier is turned off for as little as 15 
minutes, I will have allergy symptoms in the bedroom that the air purifier 
is in (but not running).

The filter in the Honeywell HEPA air purifier is much more restrictive than 
the 3M allergen filters for the furnace.  You won't have to worry about an 
allergen filter restricting airflow in your furnace, at all.

But unless the fan in your furnace/AC unit is running 24/7, the allergen 
filter in it will do you no good at all.  Air has to be CONSTANTLY filtered, 
or else levels of allergens in the air will start to rise within just a few 
minutes after the filter stops filtering air.  But if you could keep the fan 
in your furnace / AC unit running 24/7, that might do more harm than good. 
Depending on where your air outlets are, the (filtered) air movement could 
be stirring up DUST.  So you'd have cleanER air moving dust around.

On a side note, I'm very suspicious of the Sharper Image Ionic Breeze type 
air purifiers, though I've never owned one.  I know my Honeywell air 
purifier unit has to move a LOT of air CONSTANTLY to keep the level of 
allergens in the room below the threshhold that will trigger my allergy 
symptoms.  While I don't doubt that the Ionic Breeze will be somewhat 
effective, I very much doubt that any air purifier without a fan will be 
able to filter ENOUGH air to make a significant difference for someone who 
suffers from allergies.  But if someone can find the CADR rating of the 
Ionic Breeze type air purifiers, my opinion of them might change.  (I 
suspect CADR must be way too low on the Ionic Breeze units)  -Dave