Choosing the Best Whole-Home Air Purifier for Your Home

Indoor air pollution is a serious health concern for many Americans. People spend much of their time inside their homes, where pollutants are typically more concentrated than outdoors. Some pollution in the home is unavoidable. The best way to protect your household is with an in-duct air purifier. Many different air purifier technologies are available. Let’s explore what you should know about them to make the right choice for you.

Air Changes Per Hour

Treatment volume is the total area in which you want to purify the air. In this case, it’s your entire home, and the industry generally measures treatment volume in square or cubic footage. Many air purifiers function by moving air through a series of filtration stages. Cubic feet per minute (CFM) is the measure of how much air they move. It’s important to have a high enough CFM for the size of your home.

One way to do this is to consider the air changes per hour (ACH) that an air purifier provides. If an air purifier delivers 4 ACH, it filters all the air in the home four times an hour. The Centers for Disease Control and Prevention (CDC) recommends 4 ACH as a minimum. Most systems on the market provide at least 5 ACH, which many experts agree is ideal for the average household. You may need 6 ACH or higher if someone in the household has a serious respiratory condition.

Clean Air Delivery Rate

ACH indicates how much air an air purifier filters, but it doesn’t indicate effectiveness. That’s where the clean air delivery rate (CADR) comes in. The higher the CADR, the more effective the filtration overall. You can use this rating to compare one air purifier with another. 

How high a CADR you need depends on various factors, and your installer can provide you with an accurate estimate. As a guideline, the industry recommends the two-thirds rule: Target a CADR that equals two-thirds of the square footage. If you have a 2,400-square-foot home, for instance, you’d target a CADR of at least 1,600.

Mechanical Filtration

Traditional air purifiers function by forcing air through a series of filter media stages. Often, these stages include one or more mechanical filters. Mechanical filters are effective at trapping airborne particulate matter, such as:

• Dust
• Pollen
• Pet dander
• Textile fibers
• Mold and other fungal spores

Many air purifiers have a prefilter. Prefilters trap the largest particulate matter. They’re often relatively inexpensive and swapped out every several months. That approach preserves the more expensive primary mechanical filter. The primary mechanical filter is often a thick, pleated filter that you swap out every six or 12 months.

The HVAC industry uses the minimum efficiency reporting value (MERV) to measure filter effectiveness. MERV is a scale that ranges from 1 to 16. Note that you may see MERV ratings up to 20, but you won’t need anything that high. HVAC systems typically support between MERV 8 and 13 for their return vent filters. Air purifiers often support MERV 14 or higher. At MERV 16, a filter will trap at least 95% of the particulate matter that passes through.

Many manufacturers use a high-efficiency particulate air (HEPA) filter instead. HEPA filters provide performance beyond the MERV scale. They trap at least 99.97% of all particles.

Ionization

Some air purifiers can charge particles and then disperse them. This process can be an alternative or complement to traditional mechanical filtration. These particles travel throughout the home and bind with contaminants, thereby neutralizing them. There are some advantages to this approach. Filtration occurs beyond just the ductwork. In addition, some of these particles can bind to contaminants on surfaces.

One way to achieve this effect is through ionization. That occurs when the system charges an electron. Some systems use a catalytic process involving ultraviolet light. One of the newest approaches involves dispersing hydrogen peroxide molecules. Ionization sometimes gets a bad rap. The problem is not ionization but rather ozone generation, which negatively impacts air quality. Note that the top ionizing air purifiers are ozone-free products.

Absorptive Filtration

Ionized particles can also bind with many gases and airborne chemicals. Traditional mechanical filtration is not effective at neutralizing those substances. For this reason, many air purifiers have some form of absorptive filtration. Activated carbon is a commonly used medium. It’s a manufactured form of carbon that’s highly absorptive. It’s effective for odor control. It also neutralizes all the gases and chemicals that it absorbs.

Ultraviolet Germicidal Irradiation

Mechanical filtration isn’t effective at trapping bacteria, viruses, and other pathogens. Ionization is more effective, but how effective is a matter of debate. What’s not debatable is the effectiveness of ultraviolet (UV) lamps. They can neutralize more than 99% of pathogens.

Generally, the best practice is to pair an in-duct air purifier with an in-duct UV lamp. Air purifiers are most effective when there’s a high rate of air movement. UV lamps, on the other hand, are more effective when air moves more slowly, and there’s greater exposure time.

There are also on-coil UV lamps. An HVAC technician can add such a lamp to the evaporator coil of your air conditioner or heat pump. These lamps are effective at helping to avoid microbial growth in systems that are prone to it.

Warranty Protection and Maintenance Requirements

Air purifier warranties can differ greatly between brands and models. Scrutinize the fine print, and review your extended warranty options. Know what maintenance your warranty requires as a condition of coverage. Understanding the maintenance requirement is important from a cost perspective as well. Annual cleaning and correcting wear and tear are usual. You should also know the filter media costs and how often you need to change them. Those details factor significantly into the system’s total cost of ownership.

Other Considerations

Choosing the right air purifier is an important step toward healthier air, but it’s not the only one. Keep your HVAC equipment clean by scheduling seasonal heating and cooling maintenance. Use an HVAC filter with the MERV rating that’s best for your system. Check it at least once a month, and replace it as needed.

If you experience high relative humidity (RH) in summer, consider a whole-home dehumidifier. Likewise, if you experience low RH in winter, consider a whole-home humidifier. Avoid air leakage through regular duct inspections and maintenance. You can also protect your air quality by air sealing your home and installing new insulation.

Whole-Home Air Purifier Installation in Portland and Vancouver

Revival Heating & Cooling is an HVAC company that provides residential services. We have locations in Portland, OR and Vancouver, WA, and we travel throughout the surrounding areas. Our technicians install, maintain, and repair all heating and cooling technologies. That includes furnaces, heat pumps, air conditioners, and ductless mini-splits. 

We have maintenance plans that can help you save money while keeping your equipment serviced on schedule. Our team performs oil-to-gas conversions. We install and repair ductwork. Our experts can improve energy efficiency with air sealing, new insulation, and new window installation. They test air quality, upgrade ventilation systems, and install air purifiers, humidifiers, and dehumidifiers. 

To learn more about these products and air quality services or to schedule an appointment, contact us at Revival Heating & Cooling today.