Author Topic: bipolar ionization  (Read 1180 times)


  • Pencil Stache
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bipolar ionization
« on: November 06, 2015, 07:02:21 AM »
DW has been complaining about a mustiness in our house off and on since we moved in (5 years ago), and we definitely had mold issues when we tried not running the AC in the summer (we live in Tampa).  That said, we recently renoed our laundry room and the inside of the walls looked good, as does the attic.  The AC is regularly serviced, so the coils / pan are clean.  An AC tech recommended a bipolar ionizer (this one:

I've never heard of them before.  Is this a real thing?  Is it safe?  In googling, I saw some concerns about ozone / free radicals, but I didn't find anything definitive.  I realize that getting one of these wouldn't be the most frugal thing, but if it actually works and isn't harmful, I'm game.



  • Bristles
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Re: bipolar ionization
« Reply #1 on: November 08, 2015, 09:42:27 AM »
I had not heard of them before your post, but a quick Google search raises the same safety concerns you have (ozone and/or reactive oxygen species lung damage). I am also not an HVAC professional, but I have done or helped with HVAC too much over the years, so take this as some thoughts from a DIY'er.

It seems that if you were to install one you would have to be careful what company/model you chose.

Before you go spending the money on actual unit, which will likely be small compared to long term operating costs associated with creating ions using electricity have you looked into other course of action?

While the coils/pan are clean, have the ducts been cleaned? I personally thought this was snake-oil, but upon seeing the conditions of the ducts when we moved into this house it was a no brainer?

What kind of filter is on the system? If it is a cheap blue fiberglass filter, you may want to try upgrading. You can buy high efficiency filters that replace standard filters, but the best option would be a 5-6 inch thick pleated high MERV filter.

How do your ducts run (especially the return ducts)? The negative pressure pulls air into the duct; in an ideal situation all of that air is pulled in from the return grills in your house, but if the duct has not been air sealed at the joints it will also pull in air from the gaps in the ducting. If your return runs through a musty place, say a dirt floor crawl space or a dusty attic, you could easily be picking up that air. The infiltrate would be worse if your return grills are under sized.

How is your house's air sealing? Could air from a musty crawl space or other source be entering the house?

Is there any pattern to when the musty spell appears, perhaps there is a triggering event? Or maybe there is a room that smells worse than others.

I have used ozone generators in the past as a "shock treatment" to knock out smells like the lingering smells (like cigarette smells). Those smells are were worse when it was warm and humid (we have no AC here).

If it were me I would try and track down the source of the smell and address it at the source before resorting to fancy additional energy consuming devices.


  • Pencil Stache
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Re: bipolar ionization
« Reply #2 on: November 09, 2015, 04:03:26 AM »
Thanks for this thorough response!

In terms of cleaning the ducts, we were told that they wouldn't withstand a cleaning (too old / thin) and replacing them would be very expensive.

We have a decent filter, but not something that thick.  I'll look into this.

As far as how it runs, my understanding is that it only pulls from the return in the hallway, where the filter is.  I'm not sure how stuff is sealed, etc., but at the same time I've done some electrical work in the attic and it's not so musty up there (hot, yes).  I think the mustiness is in the ducts themselves.  I myself don't notice it, so it's tough for me to pinpoint, but I trust my wife's nose.

As far as triggering event, my wife says she notices it when the air initially kicks on which, to me, supports it being in the ducts.  She notices it when air has been sitting in the ducts and then enters the house, but not so much when it's flowing.

So it seems to me that our situation is likely duct-based, but that we can't clean our ducts.  Given the mildness of this (my wife would agree) spending the money replacing the ducts is overkill.  I was hoping the ionizer would provide a more moderate solution, but I just don't trust it, especially w/ a baby in the house.

Thanks again!  And if you have any other suggestions, please let me know!