Indoor air quality products are often grouped together under broad terms such as air purifier, air cleaner, or air scrubber, but the technologies behind those products can be very different. A whole-home media filter, portable HEPA cleaner, UV light, activated-carbon filter, and electronic air cleaner do not remove the same pollutants or work in the same way.
The best place to start is with the problem you are trying to address. Household dust, wildfire smoke, pollen, pet dander, odors, gases, and microorganisms are different types of contaminants, and no single air-cleaning product is equally effective against all of them. EPA recommends treating air cleaning as one part of a broader indoor-air-quality strategy that also includes reducing pollutant sources and bringing in clean outdoor air when conditions allow.
For Central Oregon homeowners, the most useful approach is usually to identify the specific concern first and then choose the technology that actually addresses it.
Mechanical Filtration
For many homes, mechanical filtration is the simplest and most useful form of air cleaning. Air passes through filter media, and particles are captured as the HVAC system circulates air through the house.
A central forced-air system can use anything from a basic pleated filter to a larger whole-home media filter. Higher-efficiency filters can capture smaller particles, provided the HVAC system can maintain appropriate airflow through the filter. Coleman, for example, offers whole-home media air cleaners with MERV 11 and MERV 13 filtration designed to integrate with central heating and cooling systems.
Mechanical filtration is particularly useful for dust, pollen, pet dander, and fine particulate matter such as wildfire smoke. Because smoke is such an important concern in Central Oregon, many homeowners benefit from understanding whether their existing HVAC system can support a higher-efficiency filter or a larger media cabinet.
The filter still has to work with the equipment. A more restrictive filter is not automatically a better choice if it reduces airflow below what the furnace, air handler, or heat pump requires.
Portable HEPA Air Cleaners
Portable air cleaners use the same basic idea on a room-by-room basis. Many use HEPA filters, which are highly effective at capturing fine particles, and can be useful when a homeowner wants additional filtration in a bedroom, living area, office, or other frequently occupied space.
EPA recommends choosing a portable air cleaner based on the size of the room and its Clean Air Delivery Rate, or CADR. A unit that is too small for the space may still filter air, but not quickly enough to provide the intended benefit.
Portable HEPA filtration can be especially useful during Central Oregon wildfire-smoke events. A home with central forced-air heating and cooling might use a higher-efficiency central filter for broad whole-home filtration while also operating a portable HEPA cleaner in the bedroom or primary living area. Homes without a central duct system may rely more heavily on portable air cleaners for fine-particle filtration.
Activated Carbon for Gases and Odors
Particle filters are not designed to remove every type of indoor pollutant. Odors and gaseous contaminants require a different approach.
Activated carbon and other adsorbent materials can capture certain gases and odors by holding them on the surface of the media. The amount of carbon matters. EPA notes that air cleaners containing a substantial amount of activated carbon or another sorbent material are more likely to be effective than filters with only a thin carbon layer.
This distinction is important because homeowners sometimes assume that increasing the MERV rating will also improve odor removal. MERV ratings primarily describe particle filtration, not the removal of gases. A high-MERV filter may capture smoke particles very well while doing relatively little about some of the odors or gaseous compounds associated with smoke.
Activated carbon can be useful in the right application, but it should be selected for the problem it is intended to address rather than treated as a universal air-cleaning solution.
What Does an HVAC UV Light Do?
Ultraviolet germicidal irradiation, often called UVGI or GUV, uses ultraviolet energy to inactivate certain microorganisms. In HVAC systems, UV lights are commonly installed near cooling coils and drain pans or, in some cases, within the duct system to expose moving air to ultraviolet light.
UV does not replace filtration. A filter physically captures particles such as dust, pollen, dander, and wildfire smoke. UV is intended to affect susceptible microorganisms. It will not remove ordinary household dust or fine smoke particles from the air.
UV Lights at Cooling Coils and Drain Pans
One of the more practical HVAC applications for UV is keeping cooling coils and nearby surfaces cleaner. Air-conditioning coils become wet during normal cooling operation because moisture condenses on them. In the right conditions, damp surfaces can support microbial growth. ASHRAE recognizes cooling-coil and drain-pan irradiation as an established HVAC use of ultraviolet treatment.
Can a Residential UV Light Treat Moving Air?
UV can also be used for airstream treatment, but effectiveness depends on lamp intensity, placement, airflow, exposure time, and the organism being targeted. EPA cautions that typical residential systems may not provide enough exposure to reliably inactivate every microorganism moving through the ductwork.
For that reason, we would not describe a residential UV light as something that “sterilizes the air” throughout the home. It can be useful technology in the right application, but its role should be understood accurately.
Ionizers and Electronic Air Cleaners
Electronic air-cleaning products can be harder to compare because the terminology is not always consistent. Ionizers, electrostatic precipitators, plasma devices, photocatalytic systems, and products marketed as “air scrubbers” may use very different technologies even though they are promoted for similar indoor-air-quality concerns.
Ionizers typically place an electrical charge on airborne particles. Those particles may then collect on surfaces, combine with other particles, or be captured by a collector within the device. Electrostatic precipitators use a related approach but usually include dedicated collection plates.
Performance varies between products, and EPA cautions that some electronic air cleaners can generate ozone as a byproduct.
What Is an “Air Scrubber”?
The term air scrubber deserves particular caution because it does not describe one standardized technology. One product may use filtration and UV; another may use ionization, photocatalytic oxidation, or another process. Rather than relying on the marketing name, it is more useful to ask what the device actually does, which pollutants it is intended to address, and whether it produces any unwanted byproducts.
What About Ozone Generators?
Some devices intentionally generate ozone, while others may create it unintentionally.
EPA advises against using ozone generators in occupied spaces. Ozone is a lung irritant, and the concentrations considered safe for people are generally not high enough to remove many indoor contaminants effectively.
For that reason, we would not recommend intentionally producing ozone as a routine indoor-air-quality strategy in an occupied home. When electronic air-cleaning equipment is being considered, ozone emissions are one of the specifications worth checking.
Can an Air Cleaner Solve a Mold Problem?
Air-cleaning equipment can sometimes help with particles associated with mold, but it does not solve the reason mold is growing.
Mold requires moisture. If there is a roof leak, plumbing leak, wet crawlspace, condensation problem, or another continuing source of moisture, that source has to be corrected. A filter may capture some airborne spores, and a UV light may help limit microbial growth on a cooling coil, but neither one fixes an active moisture problem somewhere else in the home.
EPA recommends controlling the moisture source and cleaning affected materials as the primary response to mold.
This is a good example of why it is important to identify the problem before buying an indoor-air-quality product.
What About Allergies and Pet Dander?
Higher-efficiency filtration can reduce airborne dust, pollen, pet dander, and other particles as air circulates through the HVAC system. That can make improved filtration worthwhile for households that want fewer airborne particles in the home.
We would be careful, however, about promising that a particular HVAC filter or air cleaner will solve allergies or other medical conditions. Indoor air quality is influenced by many factors, and individual health responses vary. EPA notes that air filtration may improve certain symptoms in some circumstances, but results are not universal.
From an HVAC standpoint, the practical question is whether the homeowner wants to reduce the amount of airborne particulate matter circulating through the house. If so, appropriate mechanical filtration is usually the most direct place to start.
Which Air-Cleaning Technology Helps With Wildfire Smoke?
Wildfire smoke is one of the most common reasons Central Oregon homeowners ask us about air-cleaning equipment.
For smoke particles, mechanical filtration is the foundation. EPA recommends MERV 13 filtration, or the highest efficiency the HVAC system can accommodate, along with portable HEPA filtration where additional cleaning is useful.
UV lights do not remove wildfire-smoke particles. Electronic devices should not be assumed to outperform proven mechanical filtration simply because they use newer technology. Activated carbon may help with certain gaseous components and odors, but it serves a different purpose from particle filtration.
We cover wildfire smoke separately in our Wildfire Smoke, HVAC Filters & Indoor Air Quality in Central Oregon guide because smoke events also raise questions about fan operation, outdoor-air intake, filter changes, and keeping smoke from entering the home.
Whole-Home Filtration or a Portable Air Cleaner?
A central HVAC air cleaner and a portable air cleaner can both be useful, but they solve the problem at different scales.
A whole-home media filter treats air whenever the central HVAC blower circulates it. That makes it a practical way to improve particle filtration throughout the areas served by the duct system. A portable HEPA cleaner concentrates its filtration in one room or defined area and can provide additional cleaning where people spend the most time.
Some homeowners are best served by one approach. Others benefit from using both. The appropriate choice depends on the HVAC system, the home, and what the homeowner is trying to improve.
Indoor Air Quality Is More Than an Air Cleaner
Air cleaners are only one part of indoor air quality. If a pollutant can be reduced at its source, that is often more effective than trying to remove it after it enters the air.
Kitchen exhaust, bathroom ventilation, moisture control, air sealing, appropriate outdoor-air ventilation, and humidity management can all matter depending on the problem. During wildfire smoke, bringing in more outdoor air may be exactly the wrong strategy; once the smoke clears, ventilation may again become useful. Indoor-air-quality decisions should reflect both the home and current outdoor conditions.
This is why we are cautious about treating any single product as a complete solution. Good indoor air quality usually comes from identifying the source of the problem and using the simplest combination of control, ventilation, and filtration that addresses it.
How Deschutes Approaches Indoor-Air-Quality Products
When a homeowner asks about an air purifier, UV light, media filter, or other indoor-air-quality product, we first want to understand the concern.
If the goal is better filtration of dust, pollen, pet dander, or wildfire-smoke particles, mechanical filtration is usually the most direct place to start. Depending on the HVAC system, that may mean using a better filter in the existing cabinet or installing a larger media air cleaner that provides more filter surface area while maintaining appropriate airflow.
If the concern involves microbial growth on a cooling coil, UV treatment may have a useful role. If the concern is odor or a gaseous pollutant, ordinary particle filtration may not address it. If the underlying problem is moisture or ventilation, adding another air-cleaning device may not solve the problem at all.
Our goal is not to add as many indoor-air-quality products as possible. It is to understand what you are trying to improve and choose technology that actually addresses that issue.
The Bottom Line
Air purifiers, HVAC filters, portable HEPA cleaners, UV lights, activated-carbon filters, ionizers, and products marketed as air scrubbers do not all perform the same job.
Mechanical filtration is generally the most useful approach for airborne particles such as dust, pollen, pet dander, and wildfire smoke. Activated carbon can help with certain gases and odors. UV systems can be useful for controlling microorganisms on HVAC surfaces and in certain airstream applications. Electronic air cleaners require more careful evaluation because technologies and performance vary, and some can produce ozone.
The right solution starts with identifying the specific indoor-air-quality concern.
If you have questions about air-cleaning options for your Central Oregon home, contact us. We can look at the HVAC system you already have, talk through what you are trying to improve, and help determine which options are likely to provide a meaningful benefit.