UV light on HVAC question

[The King]

Tony you cut a hole in the plenum insert it and screw it on with a couple of zip screws. Space is no problem.

[Mike Hunt]

It is GREAT if you got a bunch of Peter Max posters inside your ductwork. Kind of reminds you of the good ol days back in the '70s.

[Don Ocean]

Some kinda talk from a guy whose Union meetings are held at a Bath house.

[Hell Toupee]

Note final three paragraphs.

Pollutant Destruction

Some air cleaners use ultraviolet (UV) light technology intended to destroy pollutants in indoor air. These air cleaners are called ultraviolet germicidal irradiation (UVGI) cleaners and photocatalytic oxidation (PCO) cleaners. Ozone generators that are sold as air cleaners intentionally produce ozone gas, a lung irritant, to destroy pollutants.

Ozone is a lung irritant that can cause adverse health effects.

• UVGI cleaners use ultraviolet radiation from UV lamps that may destroy biological pollutants such as viruses, bacteria, allergens, and molds that are airborne or growing on HVAC surfaces (e.g., found on cooling coils, drain pans, or ductwork). If used, they should be applied with, but not as a replacement for, filtration systems.

• PCO cleaners use a UV lamp along with a substance, called a catalyst, that reacts with the light. They are intended to destroy gaseous pollutants by converting them into harmless products, but are not designed to remove particulate pollutants.

• Ozone generators use UV light or an electrical discharge to intentionally produce ozone. Ozone is a lung irritant that can cause adverse health effects. At concentrations that do not exceed public health standards, ozone has little effect in removing most indoor air contaminants. Thus, ozone generators are not always safe and effective in controlling indoor air pollutants. Consumers should instead use methods proven to be both safe and effective to reduce pollutant concentrations, which include eliminating or controlling pollutant sources and increasing outdoor air ventilation. Visit for more information on ozone generators sold as air cleaners.

In-duct Pollutant Destruction

UVGI cleaners may not reduce allergy or asthma symptoms.

There is no standard measurement for the effectiveness of UVGI cleaners. Typical UVGI cleaners used in homes have limited effectiveness in killing bacteria and molds. Effective destruction of some viruses and most mold and bacterial spores usually requires much higher UV exposure than is provided in a typical home unit. Furthermore, dead mold spores can still produce allergic reactions, so UVGI cleaners may not be effective in reducing allergy and asthma symptoms.

There is no standard measurement for the effectiveness of PCO cleaners. The use of PCO cleaners in homes is limited because currently available catalysts are ineffective in destroying gaseous pollutants from indoor air. Some PCO cleaners fail to destroy pollutants completely and instead produce new indoor pollutants that may cause irritation of the eyes, throat, and nose.

[Jay-T]

Thanks. I went to the link which seems to give a lot of information. It's a little unclear when they mention UGVI cleaners whether they mean those cleaners in the duct system or a UV light in where the coils or drip pan are.

This part of the quote that you posted was interesting:

[Jay-T]

Thanks. I'll pass the info on to my sister-in-law.

From an EPA site that someone else posted, there seems to be some question as to how effective the UV system really are. But, they don't seem to be harmful, and if they may be helpful to some extent, and if they cost more like a few hundred dollars than a thousand dollars to have installed, I think she may want to go ahead and have it done.

I don't know of any experienced HVAC people in her area in particular that would be a good choice to use, and I don't think she does either. Obviously, she shouldn't use or go through the plumber who told her it would cost about a thousand dollars. She lives near Langhorne, Pennsylvania (I am in New Jersey). However, she and I can do some asking around through people in that area to get some suggestions or recommendations.

[Grumpy]

Good to know! Thank You

[Jay-T]

Here's a goofy YouTube.com video that I found earlier that shows the installation process:

I would have no > Good to know! Thank You

[Don Ocean]

It doesn't take a highly qualified tech to use a hole saw for the needed 1 inch or there abouts hole and insert the tube...Run a sheet metal screw into the retaining bracket and plug it into 110VAC. An Apprentice can do a laudable job. The medical profession here recommends those on a regular basis for any folks with breathing problems, mold and viruses. I personally have installed a number of them and folks seem satisfied that they work. Couldn't prove it by me though. For your technical questions, you should speak with a contractor that is knowledgeable on these subjects. Your local health department can also guide you as to their value in subduing mold etc. The building engineer at any hospital would also be of value if you can get one to take time to talk to you.

[Don Ocean]

Most manufacturers of these devices have a chart depicting how many and what size of units to install. I generally intall two units in a standard 1500 to 2000 square foot home. Do the homework first.

[HankG]

I can understand how a UV light would help by preventing growth in and around the coil. I personally doubt that bacteria, respiratory viruses, etc., spread by coughing/sneezing, etc., would be diminished. What is the velocity of the air stream (ft/min), so the contact time in about 1 linear foot or so, is nil.

[Don Ocean]

Not my area of expertise. Like I said the hospital use them...So your premise may not be valid. Suggest you seek out and pay for expert advice. The manufacturers should be able to give professional references.