Guest guest Posted April 10, 2006 Report Share Posted April 10, 2006 , It's great that you discovered the cause. I have sampled hundreds of AC units, both portable and central. Apart from moldy carpets, they are about the largest source of bioaerosol (bacteria, yeast and mold spores and their metabolic products) in a building. This is really tragic because it is so unnecessary. With high quality filtration, none of this contamination would take place. No AC (or furnace for that matter) should ever be operated with a filter having a rating less than MERV 6-8; for most of you, the filter should have a MERV rating of 11. This is true for anything that moves air and condenses water from the air, including dehumidifiers and window AC units.More than half of the portable AC units I look at are full of mold. None even come with a filter rated at more than MERV 3 and in order to install a proper filter, the material has to be cut to size and taped onto the exterior of the AC. The only dehumidifier with proper filtration is a Therma-Stor. I would not be too worried about moldy items being brought into a home and having the spores contaminate the AC. Chances are,due to the air flow, all the spores are already on the coil to begin with. Also, the types of molds that grow are rather limited: some species of Cladosporium, Penicillium and Aspergillus are the most common; there are all kinds of yeast and bacteria that grow though. Don't use corn starch body powder if you use AC because all the granules in the air end up on the AC coil where they just feed the yeast. I got asthma from my portable AC. (There's a photo of the blower in " My House is Killing Me!) The plastic was originally all white but when I looked into it many years ago (after four summers of use) the entire blower and all the supply insulation were black with Cladosporium mold. Good filtration prevents biodegradable dust from ending up on the coil. With no food for microbes, pans and drains don't clog. C. May May Indoor Air Investigations LLC 1522 Cambridge Street Cambridge, MA 02139 617-354-1055 www.mayindoorair.com www.myhouseiskillingme.com >Date: Sun, 09 Apr 2006 13:03:41 -0400 >From: Christ <antares41-41@...> >Subject: Air conditioner makeing me sick. >About a week or so ago they sprayed the asphalt in the park here >with blacktop. It was pretty bad. I normally don't admit to >chemicals making me sick. It was so bad that I decided to close up my >trailer something I haven't done since I moved in a year ago because >the mold in that monitor contaminated my living space and made me >extremely sick. I was spooked so bad by this I thought that their >would be no chance of closing the trailer and running a hepa filter >without getting sick monitor or no monitor (I threw it out). >To my surprise I felt really good when the ac WASN'T running at night >(with windows shut and hepa running) but during the day when I ran >the ac I got really sick. Than it hit me and I feel stupid for not >thinking of this possibility. The evaporator coils in the unit collect >condensate that drips into a pan that is drained outside. It never >occurred to me that mold would grow in their with a quickness, just >add spores. I made the definite connection to my ac running and me >being sick, and not running it and me being better. Actually feeling >good! Two highly contrasting situations. >This is an instance where one might think that a little bit of mold >brought in on a single book or clock radio or your shoes, or in your >hair might be innocuous. And you would be wrong because it can >migrate to your ac unit and propagate into a large colony in the drip >pan and the constantly moist evaporator coils. >I think I rectified this problem by buying one of those refillable >spray bottles and modifying the sprayer with some quarter inch >(outside diameter) hose I bought at home depot for a couple of bucks. >The hose slid tightly over the straw on the sprayer that ordinarily >goes into the bottle. I threw out the bottle and got a milk jug to >supply the sprayer. I filled the milk jug with simple green. I stuck >the hose into the milk jug and I sprayed down the evaporator coils in the ac unit with simple green waited five minutes, bumped the fan to draw the soap though the coils. Than sprayed the coils again with simple green. I did this about three times to cut though any dirt or mold build up on the coils (couldn't really see any but obviously it's there in the drip pan and/or on the coils) (air condition repairmen have a special detergent for doing this.) After this I rinsed the coils than I mixed up a mild bleach solution and sprayed it down (evaporator coils) a couple of times. (If I had ammonia I would have used this but was in a hurry.) It is to soon to tell but I think it helped markedly. I just wanted to warn others in the group that although a book or some papers that came out of a contaminated building might NOT make you react, the spores could migrate to other places in your house where conditions are hospitable (like ac unit or a leak, or refrigerator drip tray, or the bathroom etc.) and start a colony that could really be detrimental to your health. Anyone can do this maintenance on their own ac unit their selves and I would encourage it. (I don't recommend bleach or simple green or ammonia, they might be ok I really don't know what is ok to use. I just needed results right away. I am sure you could call an ac supply house and they could point you in the right direction I might have damaged my coils with the bleach because it is corrosive. That's why I made the solution relatively weak ) I just wanted to get rid of the mold as fast as possible. Most air conditioners having set all winter have had ample time to grow a colony in the drying coils and pan. Now would be a good time to service them as described above. Another problem this will solve is the drains that empty the drip pans often get algae in them and they plug up. By spraying an antibacterial on your coils it will collect in the pan and run down the drain you are inadvertently killing the algae in the drain thus preventing the disaster of the pan overflowing and saturating your drywall with water. > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 12, 2006 Report Share Posted April 12, 2006 I have a very old furnace that won't take a tight filter. Furnace people said I couldn't put a tight filter on it as it would not get enough air flow for motor, but I solved problem this way: There are two cold air returns in house. I put 3M MERV 11 filter fabric over these cold air returns. Since this would slow down air speed to furnace, I added a fresh air intake from outside of house into cold air return ductwork. This had the effect of additional air from which my furnace can pull from. I put filter fabric over fresh air intake also though. I assume the extra air return has helped furnace as it hasn't caused any trouble with this almost 40 year old furnace in the last year and a half it has been running, round the clock. Now I had better go and knock on wood! I didn't check the ac though yet, so I guess that is next. I don't have window type anywhere but I guess this applies to central air conditioner too? For central air conditioning unit, is it the part that is outside that needs to be checked? I've already checked the inside parts. > > This is really tragic because it is so unnecessary. With high quality > filtration, none of this contamination would take place. No AC (or furnace > for that matter) should ever be operated with a filter having a rating less > than MERV 6-8; for most of you, the filter should have a MERV rating of 11. > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 12, 2006 Report Share Posted April 12, 2006 Barb, Don't worry about the outside unit at all. All it does is convert the Freon from gas to liquid. This process takes place entirely outside and only the Freon comes in and goes out. The Freon is in pipes and it never directly contacts the air you breathe indoors. The Freon runs through the cooling coil which is probably inside the furnace in the same filtered air stream as the furnace air (when it is heated). So you are all set with the filtration. Keep in mind that it is always best to filter the air as close to the AC unit as possible, but if you are getting good results the way you are using the filter material (at the returns) that's fine. C. May May Indoor Air Investigations LLC 1522 Cambridge Street Cambridge, MA 02139 617-354-1055 www.mayindoorair.com www.myhouseiskillingme.com >Wed, 12 Apr 2006 01:24:56 -0000 > " barb1283 " <barb1283@...> >Subject: Re: AC making me sick I have a very old furnace that won't take a tight filter. Furnace people said I couldn't put a tight filter on it as it would not get enough air flow for motor, but I solved problem this way: There are two cold air returns in house. I put 3M MERV 11 filter fabric over these cold air returns. Since this would slow down air speed to furnace, I added a fresh air intake from outside of house into cold air return ductwork. This had the effect of additional air from which my furnace can pull from. I put filter fabric over fresh air intake also though. I assume the extra air return has helped furnace as it hasn't caused any trouble with this almost 40 year old furnace in the last year and a half it has been running, round the clock. Now I had better go and knock on wood! I didn't check the ac though yet, so I guess that is next. I don't have window type anywhere but I guess this applies to central air conditioner too? For central air conditioning unit, is it the part that is outside that needs to be checked? I've already checked the inside parts. > > This is really tragic because it is so unnecessary. With high quality > filtration, none of this contamination would take place. No AC (or furnace > for that matter) should ever be operated with a filter having a rating less > than MERV 6-8; for most of you, the filter should have a MERV rating of 11. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 12, 2006 Report Share Posted April 12, 2006 Jeff, I had the ductwork cleaned last year. There isn't any way to get filter closer to ac with this old furnace. The regular 'washable' filter in the furnace is almost always clean now when I go to clean it, so the cold air return filters are working pretty well. I can easily see when filter needs to be cleaned at cold air returns. They just look unattractive but until I can get a newer, better furnace, that is a minor thing. This year I bought some charcoal prefilter replacements for air cleaners and opened them up and laid them across cold air returns and put the 3M fabric over that, so now I have house air going through charcoal prefilter and also 3M Filtrete fabric before it goes through furnace and that has been working fine too. The charcoal prefilter material seems to last pretty long. I just changed it after using it for six months. Now all I have to do is to control humidity this summer and everything should be fine. Having a fresh air intake causes more problems in summer than winter since it drags in humid air. I thought problem would be in winter dragging in chilly air, but furnace warmed it before it got into house and air was dry, so I had no problems and I didn't notice much difference in my heat bill. However last summer I had to freq shut fresh air intake because my stand alone dehumidifiers (two-three if you include the central air one) couldn't keep up the all the humidity it was dragging in, in July/August. Perhaps some day the Therma Stor. > > Barb, > > Don't worry about the outside unit at all. All it does is convert the Freon > from gas to liquid. This process takes place entirely outside and only the Quote Link to comment Share on other sites More sharing options...
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