Replies

1. 
   Scott_Mazur | Feb 11, 2000 04:04am | #1

   *
   Fred, maybe I used the wrong terminology here. I was referring to air cleaners which remove dust particles by passing the air across electrically charged plates. Far as I know they pose no signficant restriction to air flow?

   You also assume I'm refering to filtering a forced air heating system. I suppose that's a more common use, but my interests are purely air exchange.

1. 
   Mike_Smith | Feb 13, 2000 12:09am | #2

   *.........Scott...if your heating sub is doing the things FredL describes....don't use him.....When you get into ducted heating systems there is a lot of room for bad design, poor performance, unhealthy conditions,Alternatively...the most control you'll ever have over the comfort envelope is with a ducted system ...(OK Jeff, a hybrid system, radiant floors).....From discussions with my HVAC sub, and others, it's my understanding that Electro-static filters are passe' the best available are the Hepa Media filters,,,properly installed,,, properly designed into the system and sized and designed with the right static pressures for the unit.And FredL's point about attacking the sources is good too...if you can keep people out of the house, most of your dust will disappear, along with combustion products, pets, airborne dust particles comming in with air infiltration...Once the dust is there, the biggest culprit to keeping the dust airborne is the common vacumn cleaner....switch to the new hepa filter types....or go with central vac and external exhaust...If you have hot air...talk to a good HVAC sub about a properly sized hepa media filter...b (IMHO)

1. 
   Mike_Smith | Feb 13, 2000 09:28am | #3

   *...............Scott, I'm hoping to get to Air-to-air heat exchangers in the VENT/NO-VENT thread, and I would expect that filtering polutants is going to be a very important part of that discussion....I' thinking along the lines that you were outlining....air-to -air with built in filter and also supplying combustion air...

1. 
   andrew_d | Feb 28, 2000 09:36pm | #4

   *Friends have one, the installers recommended it bec. of their many pets. Unfortunately, these folks are not big on maintenance ... do keep the device clean, the arcing when it isn't is entertaining but probably not a great condition. I wonder if they produce ozone?These things cost big bucks, no?

1. 
   Walter_R | Feb 29, 2000 02:37am | #5

   *You clarified that you are interested in an electrostatic precipatation unit which uses high voltage plates to charge and then attract particles. Installed one in my house after one year of bloody noses in my children (all seasons) (doctor indicated mild allergies). Looked at two mfgrs, Trion and Honeywell. Selected Trion on HVAC contractor's suggestion, but either unit looked good. Incidence of bloody noses almost eliminated.Unit consists of a metal prefilter (looks like grease filter on range hood) to catch large particles and then a two electonic filter. Clean prefilter and internal units once every 1 - 2 months in dishwasher (don't use dry cycle as high temp may shorten charge wire's life).Don't trust unit to catch all dust and dirt and worry that air conditioning coil will start to have buildup. Don't have enough experience to know if this is the case. If had to do it over again I would have contractor install simple 1" disposable filter ($0.80) in front (upstream) of unit to do pre-filter and remove metal prefilter from system (prefilter is not involved in charging/attracting ionized particles).Advantages: Better at eliminating microscopic particles Doesn't restrict air flow as muchDisadvantages: Higher initial cost. Higher maintanance. Higher repair costs.The bottom line is this type of unit does remove themicro particles but at a price. I'm happy because the kid's are healthier and I now get to sleep through the night.Consumer Reports recently tested these units along with other types of filters in a controlled lab environment. You might want to look up the results.

2. 
   Walter_R | Feb 29, 2000 02:44am | #6

   *Definitely produce ozone (that smell you get around arcing high voltage or lightening). Produces some quantities whether or not you have "big particles" "shorting" it out. People have different levels of sensitivity. When first got my unit, I noticed it but no one else did. The Trion unit had internal jumper to adjust high voltage level.Factory set to highest. Reduced it to "middle" and haven't noticed it since.Unit doesn't "arc" much. Since its in basement you don't hear it except if house is totally quiet. I prefer an occassional "zap" as it lets me know the unit is working.

3. 
   Crusty_ | Apr 11, 2000 05:48am | #7

   *Worked at a coal-fired power plant that had very large electrostatic precipitators to collect flyash from the coal. Had a scary experience where I had folks inside an air duct (with unit off). Didn't know they had precip energized. Were monitoring for harzardous fumes but had no bad indications. Noticed a slightly sweet odor, and then guys started getting dizzy and nauseous. Turns out it was ozone. Not sure how you'd detect this in a house, or what it'd take (malfunction) to produce a serious amount, but it might not take much for some folks to be affected

4. 
   Gene_Leger_ | May 05, 2000 08:57pm | #8

   *Gentlemmen. Sugghest you all read the article, "IS It Worht Putting In a Better Furnace filkter?"in the May.June 2000 issue of Home Energy Nagazine. It is fulll of surprises.This Canadian publication Ëvaluation of Residential furnace Filters, written by Don Fugler, is available for free to Canadian citizens from Canadian Mortgage and Housing Corporation 800-668-2642-Canada only. GeneL.

5. 
   Mike_Smith | May 05, 2000 11:24pm | #9

   *damn, gene, that 's why we pay u the big bucks.. so u can read those articles and give us the gist of them..well, is it? ((worth putting in a better furnace filter)))my opinion is that the new media filters like Aprilaire.. ((high efficiency media filter)) do a good job and are worth the money..if i read that article will, i still have that opinion? since i'm not canadian, will they send me a copy, if i promise to buy red cedar shingles ?

6. 
   andrew_d | May 06, 2000 04:24am | #10

   *My guess: no.

7. 
   jjmcgough | May 06, 2000 04:48am | #11

   *Crusty,You are just unequivocally full of shit.If your your crew was even anywhere near the stream of flow in an energized(electrically) electrostatic precipitator, they would have been nothing short of chewed up or vaporized.Which power generation plant was this?Jeffie

8. 
   Mike_Smith | May 06, 2000 03:43pm | #12

   *no.... they won't send me a copy?see counselor... there were two (2), dammit, parts to that postlet's be more careful out there

9. 
   andrew_d | May 06, 2000 10:04pm | #13

   *Objection: Compound question. And badgering the witness.

10. 
    Mike_Smith | May 07, 2000 05:58pm | #14

    *dammit... whic side of the room r u sittin on?yr representin me ....remember?

11. 
    Rich_Beckman | May 09, 2000 05:03pm | #15

    *Andrew,One word: retainer.Rich Beckman

12. 
    andrew_d | May 09, 2000 06:48pm | #16

    *Yeah, where can i get one of those?

13. 
    Mike_Smith | May 09, 2000 09:26pm | #17

    *my dotter ain't usin her's no more..

14. 
    andrew_d | May 10, 2000 08:25am | #18

    *I'm looking for $20k+ one....

15. 
    Gene_Leger_ | May 10, 2000 04:17pm | #19

    *Mike et al. Copywrite laws prevent me from quoting from the article. But let me try to gobe you the nub of Fugler's comments. Upgrading a furnace filter makes no $ents unles the furnace fan is run continuously.A continuously running fan guarantees that the filter is continuously working. Another surprise finding was that using a better filter, even the highest efficiency filters, does not make a big difference in the amount of house air particle concentration.Finally, the electrostatic filter is not passe. In this testing progrm the ESP--electrostatic precipitator-was found to be the most effective filter. I hope this helps. Sorry I can't be more specific. GeneL.

16. 
    andrew_d | May 10, 2000 07:30pm | #20

    *Hey, Gene, there's a "fair use" exception to the Copyright Act -- limited quotations for purposes of review, etc. They mostly don't want to see wholesale copying or commercial exploitation of a protected work ... it is a federal crime. Heck, good quotes increase the chances of reprint requests.

17. 
    Cliff._Johnston | Aug 13, 2000 06:12pm | #21

    *We installed an electrostatic air filter on our previous house HVAC.Several comments: 1. It was very effective as a filter.2. There was a noticeable odor due to the production of ozone by the unit.3. Ozone speeds up deterioration of many interior household items, ie: furniture, drapes, etc., etc..4. Ozone has been implicated in the disease asthma. Our son was raised as an infant in that house and has terrible asthma. My wife's asthma got worse. Coincidence? I don't know, but I wish now that I had never installed the unit, just on the chance that...Best of luck,Cliff.

18. 
    Gene_Leger_ | Aug 15, 2000 07:04pm | #22

    *Scott. see the May/June 2000 issue of Home enmergy Magazine. Excellent article on furnace filters and electroststic filters. GeneL

19. 
    Frank_H._Biscardi | Aug 17, 2000 06:46am | #23

    *Guys,I am not certain if these devices make Ozone. However if they do it could be a health hazard.Ozone is a reactive oxygen species that is an incredible oxidizer. It is the main non-particulate component of smog. Concentrations greater then 0.4 ppm are not advisable. Duration of exposure, minute ventilation ( how much you are breathing/minute) and the presence of any underlying lung disease determine health effects. Some people are more susceptible then others. The unit may not make much ozone, but you may get considerable concentrations in small rooms with limited air flow exchanges.I have bronchoscoped many subjects as part of air pollution research for the EPA who were experimentally exposed to (LA-like concentrations) of ozone. The airways look very red and inflamed.As a pulmonologist, I can't see any reason why someone would intentionaly expose themself to ozone.Frank

20. 
    andrew_d | Aug 18, 2000 08:04pm | #24

    *Ah, so you haven't seen the ozone generating air fresheners? A guy who was moonlighting as a salesperson loaned me a demo and tried to convince me that the ozone was good because it filtered its way up into the depleted ozone layer ... and his day job was at EPA!I think the amount of ozone produced depends on how well the filter is maintained ... they start to arc as they get clogged. Judging from how well most homeowners maintain their equipment, almost all of these filters probably produce a lot of it. ("But I don't want to clean it .. it's yucky!")I grew up in LA. Ozone bad, you can feel it burn.see http://www.crest.org/sustainable/greenbuilding-list-archive/9611/msg00089.html ... and there is tons to read about electrostatic filters online ... do an altavista search

21. 
    Gene_Leger_ | Aug 18, 2000 08:41pm | #25

    *Gentlemen. May/June 2000 issue of Home Energy on furnace filters deals with the ozone generated by electrostatic filters. I don't know if this issue is available on their web page... http://www.homeenergy.org. It is worth reading. GeneL.

22. 
    Frank_H._Biscardi | Aug 18, 2000 10:27pm | #26

    *Andrew,You are right about the home air freshners. There is some guy wandering around the Shenandoha Valley selling these things. They sure do make a nice clean smell. There is a big difference between Stratospheric Ozone (good) and trophospheric Ozone (bad).These things should really not be used.The only blessing is that most people loose their response to Ozone after about three days.Frank

23. 
    FredB | Aug 19, 2000 07:37pm | #27

    *They don't have the current issue online yet. But there is one a few years old that pretty well summarizes what I know about electrostatic, electronic and hepa filters. Any changes of note?

24. 
    Gene_Leger_ | Aug 19, 2000 09:16pm | #28

    *FredB I don't know which back issue you mean so I can't comment on any changes. GeneL

25. 
    FredB | Aug 21, 2000 06:50pm | #29

    *Go to the site. I think the online article is dated 1996. That is what I was referring to.

26. 
    Gene_Leger_ | Sep 04, 2000 12:11am | #30

    *FredB et al. There is a new electrostatic filter on the market wh ich claims to be the best money can buy. It is called the Aprilaire Electronic Air Cleaner. Model 5000. for more information cal l 800-334-6011 or e-mail [email protected]. GeneL.

2. 
   Scott_Mazur | Sep 04, 2000 12:11am | #31

   *
   Experiences?