Hyper-sensitive customer needs charcoal filter?
I've got a resi customer who's become hyper-sensitive to chemicals. His wife tossed all the chemical cleaners in the house, and switched brands till he was ok. Even his old shirts on hangers had to be rewashed so he could work through a day.
Now when the neighbour's clothes dryer blasts his house with fumes he gets sick. I told him to seal the doors and windows tight. The atmospheric furnace will be replaced with a direct vent model.
I'm looking at a air-to-air HRV to put in to pressurize his home with clean, filtered (HEPA) air.
But what you you suggest for getting the chemical smells out? I've heard charcoal filters work but have no experience with them?
Charcoal filters work well on pulling out most odors without adding any other chemicals. These are made in pleated designs in all sizes. Most HEPA filters also have a charcoal or VOC component
The problem with the Lennox Pure Air systems is that your customer might be sensitive to some of the chemicals that are created through the chemical reactions of the photocatalytic oxidation.
Very very few people have true chemical sensitivity. My experience is that dealing with this type of individual takes a great deal of care and dilligence. Even something as minor as the lubricant used on the HVAC system can set someone off.
HRVs are not designed for pressurization. Aside from the heat recovery, people put them in for balanced ventilation. (instead of exhaust fans or a fresh air intake on the return air duct)
Originally Posted by D'Laine
I am not a pro - but there is a supplier of filters for the Aprilaire/spaceguard series (which I have) that sells replacement filter impregnated with charcoal.
The downside of these charcoal replacement filters is that they have a lower MERV rating than the non-charcoal media – but they do provide some chemical/order filtering on top of the normal dust/allergen filtering.
Here is the link http://www.oxyfilters.com/oxy-charcoalbear-space.html
I dunno if the guy has asthma. If he does, my research clearly and convincingly eliminated any kind of "electronic" filtration, like Trane CleanEffects or any other electrostatic particle precipitator using charged metal plates. All of the electronic air cleaners (as opposed to HEPA filters and media filters) generate a minute quantity of ozone, which is a lung irritant. Even in tiny quantities, ozone will cause asthma sufferers to be more sensitive to other irritants and indoor air pollutants that, which will trigger asthma attacks.
For my house and my wife with asthma, I decided to go with a fresh air ERV, a HEPA filter, which has to unfortunately be in a bypass configuration, and a 5" pleated media filter (in addition to the regular filter at the return). No electronic filter. We shall see how well it works! I spent quite a few hours researching this, and after reviewing the EPA's Indoor Air Quality website and talking with the American Lung Association's IAQ folks, it was clear just what should be done with HVAC for an asthma sufferer.
It is a fact that positive pressure in the house would inhibit infiltration. Depending on the climate that may be a good idea -- Lstiburek published research supports this, although there is a legitimate fear of moisture getting into the wrong places in heating climates, if the house is not built tightly to Lstiburek Building America standards.
But if the house is not tight, it would require a whole lot of supply air to achieve measurable positive pressure. While infiltration would be inhibited, the effect would be far less.
With those caveats it would seem a supply only ventilation system may be preferable to the HRV. More benefits at far lower cost. I surely would prefer that in my hot-humid climate (perhaps via ventilating dehu), but where is the customer in question?
Hope this helps -- Pstu
I understand the ERV from Stirling Technologies is designed to run using more supply than exhaust. No doubt that compromises the ability to transfer heat and humidity.
P.P.S. Make no mistake that I would want humid outside air to go thru conditioning process before being introduced to indoors. A fresh air vent would do that, a ventilating dehu would do that especially well. I do not believe an ERV or HRV would be as effective.
Have used charcoal faced pleated filters in commercial buildings. They load up quickly and loose their odor elimination capabilities within 2 weeks. They come packaged in plastic and as soon as they are opened to the atmosphere, they start to degrade. I have used 12 inch diagonal canisters that were filled with charcoal pellets on air intakes that drew from street level. Those worked very well but had many, many more times the activated charcoal than a pleated filter.Charcoal only removes odor.
I'm kind of tending to think it's not odors per se that cause this guy problems, but allergens and stuff. I'm betting he has bigtime allergies and maybe asthma or some other lung disease. If you can find out for sure what his lung problems are, I think you'll have better success in fixing their IAQ complaints.
In other words, there may be things that don't have an odor that set this guy off - like some sort of chemicals present in the neighbor's stinky dryer no-static sheets or something. IOW, you could kill the odor and still pass the chemicals, and the guy's still got a problem.
Hopefully the guy's been to a specialist and can tell you in detail exactly what the official medical condition(s) is/are so you can find the appropriate IAQ solution and not waste his money and not make things worse (like with my wife and an ozone-generating air cleaner).
Chemical and oder sensitivity can trigger asthma attacks - in addition to allergens.
Besides having whole home filtering - many asthma specialist recomment a portable hepa aircleaner in the bedrooms. Since you spend anywhere from 6-9 hours in your bedroom this can help.
Here is one such heavy duty portable hepa filter with carbon filter for chemicals.
Charcoal can do more than just remove odors. In a chemical plant situation a charcoal canister is the obvious and simple way to capture dilute chemicals which should not be released. One example would be removing cyclic hydrocarbons which are clearly toxic in small amounts. I do not know whether that could ever apply to the original poster's problem, but I do respect the ability of charcoal to absorb chemicals, not just odors.
Hope this helps -- Pstu
I think you're right PSTU. IIRC one of the HEPA portables I bought once for my wife had a charcoal canister in it that was supposed to remove fumes and gases and such.
Originally Posted by pstu
"Charcoal only removes odor."
Sorry, I meant to say on charcoal faced filters there is not enough charcoal to absorb and retain gas infiltration. Charcoal canisters definately do.