FAQs about UV Lights and Indoor Air

September 29, 2020

If you’re interested in improving indoor air quality, you may have heard about UV lights. This is a relatively new technology that has the potential to help clean air, but it is frequently misunderstood. To figure out if your property can benefit from UV-light filtration, it is helpful to learn more about how the process really works.

Is the UV Light Used in the Same Way as Rays From the Sun?

UV light is often closely associated with sun rays, which also contain ultraviolet radiation. However, it is important to keep in mind that the rays used in HVAC systems are not identical to the rays from the sun. The types of UV wavelengths we see from the sun are mostly UVA and UVB rays. Meanwhile, the type of UV used in HVAC systems is UVC light. Often called germicidal UV, UVC rays are very small and energetic. This allows them to degrade pathogens far more quickly than the sun’s rays can.

What Sorts of Pollutants Can UV Light Kill?

When people first hear about UV lights, they often wonder whether a simple lamp is really all that effective. The reality is that there is a lot of scientific research supporting the efficiency of UV lights. Studies have found that certain harmful organisms die when exposed to specific wavelengths of UV lights. The type of UV lighting used in HVAC air purification systems can kill:

  • Viruses
  • Mold spores
  • Fungi
  • Bacteria

Do You Need UV Air Purifiers If You Have a Good Air Filter?

Air filters do a great job of blocking larger particles like pet hair, pollen, or dust. However, most dangerous bacteria and viruses are incredibly small. For example, the typical SARS-CoV-2 virus is one four-hundredth the size of a human hair. To be small enough to catch these tiny particles, filters would have to be so dense that they would virtually block airflow. This is where UV purifiers can be helpful. Unlike air filters, they do not impede air stream and physically block pathogens. Instead, they just instantly kill them and let your air cycle normally.

Will UV Lights Completely Purify Your Air Right Away?

The answer to this question depends on what sort of UV light system and the volume of air that passes through it. Research from 2012 found that UVC light could instantly kill 97% of dangerous, antibiotic-resistant bacteria in hospitals. So, the air will be purified as soon as the entire volume of air passes by the lights. Some commercial systems used in hospitals and labs completely blanket the inside of the HVAC system, constantly killing pollutants. Additionally, they have powerful air circulation to quickly push through a large volume of air.

Residential systems tend to be smaller, and it takes longer for the entire volume of air to circulate through them. These systems slowly yet continuously clean the air. Over time, this leads to drastically lowered viral and bacterial loads in your indoor air. Home UV systems may not instantly zap all pathogens, but with a little more time, they still do a great job of cleaning the air. According to the EPA, passing all your air through the UV light kills roughly 99.9% of contaminants.

Is UV Light Dangerous for Humans to Come in Contact With?

There are a few different potential dangers to be aware of when using UV light in your air system. One thing that worries many people is ozone. Technically, it is possible for UVC light to create ozone byproducts, which can be dangerous to breathe on a regular basis. However, most air purifier manufacturers use special coatings that prevent their bulbs from generating ozone.

Just like you can get a sunburn from too much UVA light, the UVC light in air purifiers can also be problematic. This powerful purifier can harm human cells just as quickly as it harms bacterial cells. However, this is only an issue if you are exposed directly to an unprotected bulb while it is. UVC air purifiers have the UV lights inside your HVAC system, where the rays of light do not fall directly on you. This helps prevent any issues like skin burns or eye damage.

How Are UV Lights Added to HVAC Systems?

There are a few different ways that you can incorporate UV lights into your HVAC system. The most common type is a UV lamp that is attached to your evaporating coil. The coil area tends to have a lot of condensation and moisture buildup, so a UV light there will address any mold growth in this area. This helps to keep mold and mildew from contaminating your air.

Another option is placing your UV lights directly into the ductwork. These lights go over the return vent, where air is pulled into your HVAC system, so they can thoroughly clean all the air that flows through your system. Its main goal is to treat and sanitize the air itself. It will not do much to clean the components of your HVAC system.

Which Type of UV Light Purifier Is Best?

The best type of UV light purifier will just depend on your needs. If your main focus is improving indoor air quality, then an airstream UV purifier is the best option. These also tend to be easier to install and a little cheaper. However, there are still some great benefits to coil UV purifiers as well. A dirty coil harms indoor air quality and reduces system efficiency. Therefore, investing in an extra purifier to clean the coil can also improve your overall indoor air quality.

Is Running a UV Light Expensive?

The HVAC system already uses a substantial amount of energy, so it is understandable that some do not want to put any more strain on their system. However, the reality is that UV lights do not use that much electricity. UV lamps are actually quite dim, so there is not a huge power durian. On average, it costs about 7 cents per day to operate a germicidal UV lamp inside your HVAC system. If you are worried about costs, you can select versions that are connected to the blower for your HVAC. They will only turn on when the blower is running, so they will save even more power.

Do UV Lights Require Maintenance?

There is little maintenance involved with the typical air purifier system. The only thing you usually need to do is replace the UV lamp bulb if it goes out. The frequency of this maintenance will depend on the product you get. Some require an annual replacement, but others may operate for years without requiring any work from you.

Have any other questions about using UV lights to purify air? As one of the leading providers of indoor air services for the Detroit area, C & C Heating & Air Conditioning can help. We offer a variety of indoor air quality services, including testing, ventilation, and filtration. Our team can also help you with repairing, installing, and maintaining your AC or heater. Call our office in Roseville now to schedule your next appointment.

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