Klbhammond
Member
Just bought a home and wanted to install a light is there a reputable brand to purchase and how difficult to install
UV light install question
- Thread starter Klbhammond
- Start date
rlitman
Well-known member
rlitman
Well-known member
OP
Klbhammond
Member
Yeah I seen some that are inward of the coils and then I seen others that look to be more air flow. Some are 24/7 on and others are on when the fan kicks on. Just curious what everyone is using and how they are running them
I have been looking at UV light for some time. If you are interested in treating the whole house air flow with a ducted system. It ain't gonna work, regardless of what the smiling people in the ads claim! The evaporator coils can be done, to keep them clean. When a bit of though is put into it, 100's of CFM going by a small bulb will do nothing.
I want to treat the fans in my mini split AC, should be ok for that!
I want to treat the fans in my mini split AC, should be ok for that!
They do work. I have had them for 15 years in my home central system. 2 17" inch long bulbs above the coil. The air has to pass through the light rays. Have serviced many large commercial systems with them in buildings and they are becoming more common now in those systems. Any plastics however get deteriorated by the UV however and you have to make sure the light is sealed inside and does not leak out ,ie hole in duct. They will flash burn your eyes and skin just like a welder. The bulbs are good for mold growth around two years , however if your trying for viruses replace them every year.
rlitman
Well-known member
Can you point me to some documents recommending how many watts or bulbs or whatever to be used with how much duct CFM or blower HP or again, whatever?
https://ultravation.com/
This is the manufacture of the ones i have in my system , not too much was out there when these started to hit the supply houses. One word of advise is look at the replacement cost for bulbs. You could be stuck going to the oem for bulbs. I was able to get replacements for my first set for a good price from Atlanta light bulbs.25-28.00 ea. The sockets decomposed and the manufacture warrantied the unit with a upgraded version but used a different bulb.. All was good until i went to replace the bulbs the next year.. Started at 65 ea. Now they are around 100 ea. I found one other supplier that has them for 40.00 ea.
This is the manufacture of the ones i have in my system , not too much was out there when these started to hit the supply houses. One word of advise is look at the replacement cost for bulbs. You could be stuck going to the oem for bulbs. I was able to get replacements for my first set for a good price from Atlanta light bulbs.25-28.00 ea. The sockets decomposed and the manufacture warrantied the unit with a upgraded version but used a different bulb.. All was good until i went to replace the bulbs the next year.. Started at 65 ea. Now they are around 100 ea. I found one other supplier that has them for 40.00 ea.
LS6 Tommy
Well-known member
Snake oil. If the worked, they'd be used in pharma, lab and clean room HVAC. They are not. HEPA filters are.
Tommy
Tommy
rlitman
Well-known member
<sigh>
Unfortunately, it's a sign of these times that every snake oil salesman comes out of the woodwork to peddle their wares right now. For that reason, I admire a healthy dose of skepticism here.
However, UVGI (through UVC) is a proven to work technology. This is the current ASHRAE position document I can find on the subject. It states:
While ASHRAE Position Document on Filtration and Air Cleaning (2018) does not
make a recommendation for or against the use of UV energy in air systems for minimizing the
risks from infectious aerosols, Centers for Disease Control and Prevention (CDC) has approved
UVGI as an adjunct to filtration for reduction of tuberculosis risk and has published a guideline
on its application (CDC 2005, 2009).7 (Evidence Level A*)
*A=Strongly recommend; good evidence
The problem I'm having is finding useful engineering data that's not from some shady fly-by-night that just popped up last month, or someone trying to hawk some counterfeit technology. And right now, that's all I'm finding on the market. It seems that the established and trustworthy businesses were just not up to the task of scaling to the current global needs, and are hunkered down servicing their tried and true customer base.
UVGI is widely used in hospitals and food processing plants. Your examples of "pharma, lab and clean room HVAC" really are a poor fit for UV, when HEPA makes much more sense, but UV can be a good fit elsewhere.
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LS6 Tommy
Well-known member
Note the word "adjunct". That means "in addition to". Without HEPA, it's next to worthless. UVGI is mostly used for surface sterilization, not media sterilization. That's why labs and pharma don't use it on HVAC. Like I said, it's snake oil in residential HVAC applications.
Tommy
rlitman
Well-known member
Again, labs and pharma don't have active sources of infectious agents.
Hospitals and food plants do, which is why they use UV.
My personal experience with UV is with fish keeping (I've been using UV sterilizers for over 20 years now), and it's ability to kill algae is positively amazing. I'm quite familiar with it's use in all sorts of water filtration, where is is solely used as "media sterilization", so I'm not buying your argument at face value. In fact, UVGI was first proven to inactivate airborne microorganisms back in 1935.
However, I do still agree that many (most) people are out there selling snake oil. And it's been a royal pain in my *** wading through all of them.
Many of the big HVAC manufacturers have UVGI products in their lines, though they're selling them as a product that prevents the coils from getting a musty smell. Well, that smell isn't exactly something healthy to breathe, so there's a positive use (albeit of surface sterilization), right there. Here's an article from 2016 that claims efficiency gains due to coils staying cleaner.
Anyway, I think I found something useful to start with:
https://www.ashrae.org/file library...id-19/si_a19_ch62uvairandsurfacetreatment.pdf
And this NIST presentation from January of this year (what timing!) has fantastic numbers for me to work with:
https://www.nist.gov/system/files/documents/2020/03/23/Panel IV Ashish Mathur presentation.pdf
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LS6 Tommy
Well-known member
No infectious agents in Pharma? You don't work in the industry do you?
We have to wear masks all day, get our temp tested as we come in every morning and each and every time we go into a clean room or any area above Class C.
Again, hospitals and food processing are NOT using it on conditioned air, just for surface decon.
I will admit I used the term media too loosely. U/V works very well with a water. Every decent hot tub, spa and a lot of pools use it. I've been using UV in my fish tanks for decades, too, but only to eliminate green water born algae. The available UV units for aquariums are too small and don't have enough dwell time to effectively sterilize the water. That is the exact same reason it doesn't work for HVAC. Not enough dwell time for the air to be sterilized.
Tommy
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