When it comes to in-home air purification, most homeowners opt for standalone air filters. These devices are often loud and only filter the air in one room at a time, but we put up with them because they seem like the cheaper option. Some units can be quite expensive, however, and require filter refills to maintain effectiveness. The less expensive options may not be adequately filtering small particles out of the air that the homeowner was trying to mitigate in the first place.
Luckily, there are other options on the market equipped to handle effective indoor air sanitation. One of the newer technologies to emerge is that of UV sanitation devices. Learn more below about how UV light can work with your HVAC to provide you with cleaner indoor air.
What is UV Sanitation?
UV light has been proven to effectively kill harmful bacteria, viruses, and mold lurking about on surfaces. Because it is so effective, hospitals, restaurants, and many other industrial settings use UV light for sanitation in high-risk spaces and to clean instruments and tools exposed to biologicals.
UV light attacks living organisms by targeting specific DNA and RNA molecules to denature a cell. For single-celled organisms such as bacteria, viruses, and mold spores, this can mean a death sentence. When the strength of the UV light is high enough and exposure time is long enough, UV light can kill 97-99.9% of bacteria, viruses, and mold.
This discovery has exposed the world to a variety of practical applications for UV light. While disinfectants can create harmful gases and cause allergic reactions when used, UV light is generally safe for most indoor environments as long as the light isn’t directly exposed to anything other than the air. Some UV-C lights will produce ozone, which can be harmful to your health. If this is of concern to you, make sure to check how your UV light handles ozone when choosing a UV sanitizing device.
How does a UV Air Sanitizer work in your HVAC?
UV air sanitizers transfer the concept of light-based surface sanitation to indoor environmental purification by way of your HVAC. Since airflow must travel through your HVAC before blowing throughout your house, it makes perfect sense to treat the air with purification techniques at the source and within the HVAC itself. The caveat is that the particles you are trying to rid from your air must have enough exposure time to the UV light to be killed before blowing throughout your home.
There are two places within your HVAC that are ideal for UV sanitation: in the ducts and on the coils.
Coil UV Lights: These are directed toward the condenser coils to prevent surface microbial growth. Because the condenser coils pull moisture from the air, this moisture paired with dirt and debris commonly stuck to the coils can be a ripe environment for microbial propagation. Directing UV light toward this area prevents bacteria, viruses, and mold from growing within the machine and blowing through your air vents when the air conditioning is running. Since the particles aren’t going anywhere when they are stuck to the coils, the light is exposed long enough to kill most, if not all, of the microorganisms on the coils.
Airflow UV Lights: These are placed within the return air duct to kill microorganisms as they enter your system. Either a stick-shaped or u-shaped light will emit radiation onto the airflow as it is passing through the duct to kill microorganisms within the air. Certain types can be left on indefinitely, while others only turn on when the HVAC motor is activated. Airflow may be too fast to catch all of the microorganisms as they pass through the system, but a good portion will still be exposed each time air filters through the intake vent and under the UV light.
You can choose to install one or both types in your HVAC for maximum sanitation. A professional HVAC technician can help you determine which course of action is best for your sanitation goals.
You may hear HVAC UV lights referred to as “lights” or “lamps”, and they may be described as “purifying”, “sanitizing”, “sterilizing”, or “germicidal”. There is no real difference between all of these modifiers when it comes to UV lights. They work in the same way to kill harmful microorganisms in the air.
Since UV lights only directly kill living organisms, they won’t do much for larger dust particles or allergens floating around in your air. For this reason, UV lights are best paired with another type of air filter. If no air filter is used, the bacteria and viruses may be blocked from the UV light by the bigger particles, which will significantly decrease the effectiveness of your UV sanitizer.
Other Ways to Support Air Sanitation
It is important to use a UV sanitizer with another layer of air filtration within the HVAC system to maximize its effectiveness. You can also support your system by maintaining your ductwork. If your ductwork is damaged or dirty, it may diminish your UV sanitizing efforts.
Air Filters
Most commonly, homeowners will install an air filter to trap larger particles such as dust, pet hair, allergens, smoke, and smog. Not all air filters are created equal, and you may pay close attention to the MERV ratings of various filters to choose the best one for your indoor air quality goals.
A typical MERV rage for air filters you may find at the store will be between 5 and 13. The lower the number, the fewer particles it will filter out of the air. Higher rated filters not only trap smaller particles, but they will trap a higher percentage of them as well.
You may be tempted to either buy the cheapest filter to save money or the one with the highest MERV rating to filter out as much as possible. However, neither of these strategies may help you or your HVAC in the long run. While a lower rated filter is better than no filter, you may want to pay attention to the filtration power of higher rated air filters if you are concerned about environmental pollutants in your air. Take a look at the guide below to determine which type of filter is best for your home.
MERV 1-4: Will filter out fewer than 20% of particles between 3 and 10 microns, including dust mites, pollen, spray paint dust, and fibers.
MERV 5-8: Will filter out 20-85% of particles between 3 and 10 microns, including mold spores and hair spray.
MERV 9-12: Will filter out 85% or more of particles between 3 and 10 microns, plus 50-89% of particles between 1 and 3 microns, including auto emissions.
MERV 13-16: Will filter out 85% or more of particles between 3 and 10 microns, 90% or more of particles between 1 and 3 microns, and 75-95% of particles between 0.3 and 1 microns, including bacteria, smoke, smog, allergens, and viruses.
Some HVAC systems begin to have issues with air resistance when filters go above an MERV 13 rating. These and HEPA filters are best used in industrial settings such as hospitals but may damage your residential equipment. When looking for the best air filter for your HVAC, look for one that is pleated and is at least MERV 8 in rating. If allergens, smoke, viruses, and bacteria are of concern, look for MERV 12 or 13.
Of course, these filters work best when they are regularly replaced. As they trap dust, debris, and other particles, they can start to slow airflow through the HVAC and lose their efficiency at trapping new particles. Excess dust will settle inside your HVAC and can affect the inner workings of your system, particularly the coils and fan.
It is recommended to replace an air filter every couple of months. If you struggle with allergies or have pets that contribute to high number of particles in your air, then you may even switch out your filter every month for higher effectiveness. By staying consistent in filter exchanges, not only will you support your overall health and wellbeing, but you will support the longevity of your air conditioner, furnace, and ducts as well.
Duct Cleaning
If you have used cheap filters in your HVAC in the past, chances are your ducts have a collection of dust, debris, and germs accumulating in them already. If you install a UV light without first cleaning out the excess matter in your ducts, then it may take a while for the UV light to kill all of the germs floating around inside, if it can even reach them through all of the dust. If you are considering a UV light for HVAC sanitation, start it off right with a thorough duct cleaning first.
A professional duct cleaning service will rid your ducts of the excess particles floating around in your system that a UV light won’t be able to neutralize. Performing regular duct cleanings will help make your UV that much more efficient against the microorganisms it targets and improve your air quality even without a UV light.
Sealing Ducts
Your ducts could also be compromised by a tear, hole, or gap that is letting in dust and debris. Inflow isn’t the only issue when it comes to structural damage in your ducts. At the same time, these imperfections are reducing the overall efficiency of your HVAC by allowing airflow to escape from the system. A duct inspection can help you determine if these issues are present within your system.
Sometimes ducts weren’t installed correctly to begin with, and other times damage could have been inflicted by critters, corrosion, or other external factors. Even small pinprick holes can significantly reduce the efficiency of your HVAC. A professional inspection with specialized tools is worth it even if you aren’t planning on installing a UV light, as you can find and repair damage that is affecting your system.
Fixing breaks in your ducts not only support your system’s efficiency, but it helps with your air quality as well. Dust and other particles won’t enter your system as easily, which can also help a UV sanitizer work as efficiently as possible against germs.
HVAC UV Installation
UV lights are simple to install in an HVAC and not too expensive for cleaner and better-quality air. Calculating the cost of professional installation and the device itself, you could expect to pay less than $1,000 to install a UV light in your system. Replacement lamps cost anywhere between $15 and $100. Most lamps will last about a year and are easy enough for homeowners to replace themselves.
An HVAC professional can consult with you on your air quality goals and which type of UV lights are best for your system. For more humid areas of Maryland, both a coil UV light and airflow UV light will help improve the air quality the most. Drier areas may not have to worry as much about microorganisms proliferating in the air, as there is less moisture. So, just a coil UV light may be sufficient.
Are UV Lights worth it?
If you consider all the ways you can purify your air and make the air quality better in your home, you may wonder if UV lights are worth it. The answer will depend on your particular home, lifestyle, and allergies.
Household cleaning products may leave behind scents and other harmful chemicals in the air, decreasing your air quality rather than improving it. While cleaning your home regularly does help support the overall indoor environment in your home, you may want to find a way to neutralize these by-products for your health and well-being. Furthermore, these products usually target surface-level germs and won’t get all the bacteria, fungi, and viruses floating around in your air. For this reason, you will still need to use an air filtering method to neutralize as many germs as possible.
Air filters are the next step in protecting your air quality and HVAC system. As mentioned above, different types of air filters will trap different particles. The highest rated ones may trap the most viruses and bacteria, but they may also cause a strain to your system and cause system failure sooner than expected. If you suffer from allergies and want to filter out as many microorganisms as possible without compromising the integrity of your HVAC system, then you may stick with air filters that are rated MERV 11 to MERV 13. Even these, however, don’t filter out 100% of the microorganisms in the air.
Portable air filters can filter more particles out of the air, some even touting a “HEPA” rating. However, the best units are several hundred dollars, require filter refills, and only filter the air in one room at a time. Not to mention, they typically run loud because of the fans. Continually running portable air filters in every room may not be practical for every household. You may be better off with a good enough HVAC filter, regular maintenance, and a UV light rather than loud and cumbersome portable air filters.
Running a UV light in your system isn’t going to take care of all the particles in your air. Remember, the UV light only kills microorganisms, so it won’t neutralize typical allergens such as pollen and pet dander. This is why it is imperative to use an air filter in conjunction with a UV light in your HVAC.
If you are worried about allergens, choose a higher rated MERV filter for best results. If your allergens are to mold, however, then a UV light will work great at diminishing mold spores in your air. Again, this may be more of an issue in wetter climates and particularly on the coils inside your HVAC. By using a UV light and quality air filter together, you will be well on your way to cleaner air inside of your home.
Not everyone needs a UV light in their HVAC system. Homes located in dry climates and people who are unconcerned with allergies, illness, and mold growth may do just fine with a typical HVAC air filter and other surface-level support tools. Furthermore, a UV light may create ozone, which can be triggering for asthmatics if breathed into the lungs. If your home already has issues with mold growth, however, and you want to keep yourself and your family members safe from harmful viruses and bacteria, then a UV light can only help your cause.
Using a UV light by itself isn’t going to fully support your air quality. Using an air filter by itself, particularly a poorly rated one, isn’t going to fully support your air quality. No one device or product is the magic solution to better air quality. However, it is by combining these layers that you will achieve the best indoor air quality in your home. When you are ready for cleaner air inside of your home, talk to an HVAC specialist about the best options to match your system and lifestyle.