# HEPA screens?



## veesubotee (Nov 22, 2008)

KE2KB said:


> Hi;
> My sister has serious allergy problems, so we have to keep the windows closed in the house.
> I just thought of an idea to put HEPA filtering in the windows, so that we can use fresh air on cool days instead of having to run the AC.
> 
> ...


It's been a long time since I worked with HEPA filter units, but as I recall, the specification is that they retain (trap) 99.97% of all particles 0.5 microns (diameter) and larger.

At that porosity, air will not pass freely through the material to cool your room, but requires a great deal of pressure (blowers). As a result of passing air through them, they generate a great deal of heat, so you would need cooling. Also, in any practical application, HEPA filters are fitted with pre-filters to prolong their life, as unprotected, they would soon clog. I would think the above would preclude their use as you suggest.

Now there may be some air conditioners (portable, window, etc., that may be equipped with HEPAs. Or, you can consider a centrally mounted media filter of low porosity.

I would look into other alternatives and think about using your a/c.

V

P.S., where in Jersey are you?


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## Ultrarunner2017 (Oct 1, 2008)

I probably don't need HEPA filters to block most of the pollen.
Fortunately, it's not I who has the allergy problem; it's my sister, who lives with me. I just have to keep my door closed when I have the windows open.
She has to run the AC anytime the room becomes too warm for comfort, since she cannot open the windows.
She has also been considering buying a filter as a stand-alone unit.
The problem with those though, is that they require a lot of maintenance; cleaning the filters.

We use room AC units, as we do not have a central system.

I live in Teaneck, NJ, which is only a few miles west of the GWB.

FW


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## veesubotee (Nov 22, 2008)

KE2KB said:


> I probably don't need HEPA filters to block most of the pollen.
> Fortunately, it's not I who has the allergy problem; it's my sister, who lives with me. I just have to keep my door closed when I have the windows open.
> She has to run the AC anytime the room becomes too warm for comfort, since she cannot open the windows.
> She has also been considering buying a filter as a stand-alone unit.
> ...


If your sister hangs out mostly in one room, a room-sized air purifier might do the job.

As you mentioned, "The problem with those though, is that they require a lot of maintenance; cleaning the filters", bears out what I said.

If you can reduce infiltration, it will be helpful. You'll also feel better when the humidity hits.

V

P.S., I'm in Voorhees (Camden Cnty)


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## Chemist1961 (Dec 13, 2008)

She is best to buy a small room air filter, check the room size rating for air exchange rate and also replacement filter cost before you start. If you get one with a washable mesh prefilter and a Hepa cartridge it will save you on the cost of replacement filters. I have a Bionaire unit about 8 years old which will do 1000 feet several times a day at low speed.


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## Ultrarunner2017 (Oct 1, 2008)

Hey guys;
Thanks for your advice. I am going to research room air purifiers.

FW


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