Do UV-C Light Germ Zappers Really Work?

Question

I was thinking of buying my mother a GermGuardian for her office and bedroom, but at $150.00 a pop, I want to make sure it works. The below excerpt is taken from their website. Do you think this unit can eliminate germs sufficiently in a small closed environment or does it only zap an inconsequential amount?

It harnesses the power of naturally occurring UV-C light, the same technology that hospitals use to sanitize, making it a safe way to kill germs without having to use chemicals. It is proven effective against 99.9% of targeted airborne flu viruses and other germs which cause:

•Colds
•Strep Throat
•Staph Infections
•Tuberculosis and more

Now you can use this technology in your home or office to help stop the spread of airborne germs. It also destroys odors, allergens and mold spores.

http://guardiantechnologies.com/prod_uvcair.html

Answer 1

Air assisted UV-C HEPA’s require a high air change rate to be effective. Some clean rooms, site HEPAs near cool air vents, run at 2000 cubic feet per minute. (Barring issues of air to volume ratio.)

- Gemguardian’s claims “Disinfects 10X20 room in 60 minutes.” (2)

The above claims of 700 cubic feet of air per hour (CFH) (1) or 11.67 cubic feet per minute (CFM) would mean preping the above mentioned space for the said duration prior to habitation.

Despite air assistance, having two at opposite ends of a space near a convective cold air supply, such as air ducts (4), and layout of living space will affect air circulation efficiency.

- VS. Office Bench Mark Aller Air 5000UV at 400 cubic feet per minute (CFM) and 2 ACH Effective for 1600 Sq. ft. (4) (‘What others don’t tell you’)

The focus is of Air Change rate in hours (ACH) provided by the preferred product. In alluding to weak and strong vacuum cleaners; weak air flow works less efficiently with high ceilings and large spaces. Hence, the suggestion for two of the previously mentioned based on 3.1m floor to ceiling height.

- More information required not available on the website.
Not all UV-Cs are at 254 nm required to destroy DNA cells of microorganisms. This is the least likely of probabilities to be untrue.

- Gemguardian’s Power usage 120V of electricity. (1) Vs 110 AC (Energy and Power Efficient) at 100 Watts Maximum (4). Unless long term utility bills are not an issue, disregard this one.

Though not in direct relation, references 3 to 5 for your general information.

- Other Considerations. The following air purifiers used at intensive and critical care wards in hospitals are available for the home. (6) (7)

Convention is that a number of filters are required to achieve a certain practical efficacy. UV-C does address certain issues but low powered ones might been seen as contrivances if not given the time to work.

Answer 2

My granddaughter was bringing home a lot of sickness from school - almost weekly , I got a Breeze by Ecotech and she has only been sick twice since we got it

Answer 3

I wouldn't trust that.. every hospital i have ever been in smelled clean from some sort of chemical....