Electret-treated media is useful in increasing the capture efficiency for submicron particles.
Electret-treated media is useful in increasing the capture efficiency for submicron particles.

Indoor air quality (IAQ) started to emerge as an issue of note around the time of the 1970s' oil crisis. To respond to higher energy costs of the time, the construction industry started building and remodeling homes and commercial structures to be “tighter” with advanced insulation systems and strictly controlled air infiltration and exfiltration. The goal of these tighter structures was to keep conditioned (heated and cooled) air inside to reduce energy expenditures.

One result of these tighter structures is that indoor air can become trapped to a degree inside buildings. And when that trapped indoor air contains irritating particulates or dangerous pollutants, it can affect the health and productivity of occupants. In recent years, the general public has become more aware of IAQ issues and the effect IAQ can have on one's health. Pressure, therefore, has increased to build healthier buildings that provide clean air and other indoor environmental benefits.

Thanks in part to this pressure, many members of the HVAC industry have been working to emphasize the importance of IAQ to residential and commercial customers. Many HVAC companies — engineering firms, contractors, and distributors — are looking to build their businesses by adding indoor air quality services and products to their offerings.

Unfortunately, due to lack of time, resources and training, many HVAC industry professionals aren't always well equipped to promote the real advantages of superior IAQ and the role air filters play in delivering good IAQ and energy efficiency. Instead, they often default to the lowest price and familiar products in an effort to keep customers coming back for more.

Roadblocks to selling IAQ and air filtration

 An effective air filtration strategy provides a good defense for building occupants and HVAC equipment against pollutants generated within a building as well as pollutants from air drawn into the building from the HVAC system. Given these benefits, why wouldn't HVAC professionals focus more on IAQ products and services? Kimberly-Clark Professional Filtration recently conducted a research study to identify the main roadblocks preventing HVAC industry companies (contractors, technicians and air filter distributors) from effectively selling the value that proper air filtration brings to creating healthier, more energy-efficient buildings. Key results of that research follow. Filter manufacturers and their filter media suppliers would be wise to address these issues so the value of their products can be better understood and more effectively sold to users.

Selling price or size vs. performance

 Our research found that many air filter purchasers tend to base their buying decision on the price of filters and making sure they have the right size filter for their HVAC system instead of the filters' particulate capture and energy performance. A number of them admitted as much, indicating that they didn't understand the differences between many of the filters on the market. Only a few understood that the purchase price accounts for much less than the energy cost needed to run air through the filter, as explained in more detail below. They also may be unaware of the broader health and productivity cost advantages of providing good IAQ with filters that offer superior capture of the submicron particles that can cause health problems.

MERV & submicron particles

A filter's Minimum Efficiency Reporting Value (MERV) indicates the filter's minimum fractional particle size efficiency and offers a simple basis for choosing a filter. A MERV 1 is least efficient and a MERV 16 is most efficient. Our research found that some HVAC professionals lack a good understanding of the difference among MERV ratings (see chart below).

Those without a firm understanding of MERV may also lack an understanding of the complete picture in terms of a filter's efficiency in capturing submicron particles. This is why filter manufacturers need to promote their full testing results as found in the filter's ASHRAE 52.2 report (specifically the Fractional Particle Size vs. Particle Diameter Curve). The full report provides the efficiency of the filter over three particle size ranges: E1 (very fine particles in the 0.3 to 1.0 micron range), E2 (fine particles in the 1.0 to 3.0 micron range), and E3 (coarse particles in the 3.0 to 10.0 micron range).

High E1 and E2 efficiencies are critical for achieving good IAQ and helping building occupants avoid illness due to poor IAQ. However, many pleated filters today (especially at commonly used MERV 8) have very low E1 and E2 efficiencies. In fact, under the ASHRAE 52.2 Standard, there was no minimum requirement for E1 particulate capture below a MERV 14 and no minimum requirement for E2 particle capture below a MERV 9 until very recently.

The energy equation

Our research found that homeowners and building owners/managers alike tend to resist changing their filters as directed by filter manufacturers. In some cases — primarily with homeowners — HVAC professionals referenced the “hassle” and expense consumers face when having to buy and replace filters every three months or so.

Commercial building owners looking to reduce costs may also choose to delay changing filters or purchase lower priced (and lower efficiency) filters. This strategy ends up being penny wise, but pound foolish. That is because the small amount of money saved by reducing air filter purchases or purchasing lower priced, lower efficiency filters pales in comparison to the energy and operating costs consumed due to airflow resistance from dirty filters. The more resistance there is, the more energy is needed to push air through the filters. It doesn't take long for peak energy use to offset any savings in filter purchases.

Particle sizes of common indoor air pollutants.

Resistance to new technologies

It's human nature to resist change, and our research found that filter suppliers and their customers often default to products they are familiar with. They may be unaware of the benefits of newer filtration technology that uses synthetic filter media and electret treatments to improve the filter's particle capture efficiency while not degrading its airflow resistance. Particle capture in synthetic filter media can be enhanced by adding an electrostatic charge, creating an electro-mechanical structure that attracts particles with a natural charge (and those that pick up a natural charge as they pass through the air), similar to magnetic attraction.

Electret-treated media can provide high initial and high sustained efficiency over the entire filter lifecycle. It is particularly useful in increasing the capture efficiency for submicron particles — those particles that travel to the deepest part of the lungs, where they can cause health problems.

Filter manufacturers should make those selling their products aware that it's possible for two similar filters of the same MERV (one using mechanical-only media and the other using electret-treated media) to have different filtration efficiencies. For example, a MERV 8 electret-treated media filter could have better E1 particle capture than a MERV 11 mechanical-only filter since there is no E1 requirement below MERV 11.

In fact, recent testing has showed that MERV 8 filters using electret-treated media performed on average 20 percentage points higher in E1 and E2 efficiency than mechanical filters on the market today.

In addition to its particle capture benefits, electret-treated media typically delivers lower airflow resistance in the same filter construction as mechanical-only media, which translates into reduced energy consumption and cost.

Selling tips

When filter manufacturers and their filter media suppliers devote the time and resources to helping the rest of the filter supply chain understand the true value of air filtration, everyone along the supply chain benefits, as do building occupants. Following are a few final suggestions filter manufacturers can make to their supply chain partners.

  • Selling price or size vs. performance: While filters clearly need to fit inside filter racks and housings, it is the performance of the filter in terms of particulate capture and energy efficiency that should be the key selling points.
  • MERV and submicron particles: Don't let a filter's MERV be the only data point you reference when talking about filtration efficiency. It's more important to focus on the filter's ability to capture and remove the submicron particles that cause health problems.
  • Delaying filter changes: One way to lessen the frequency of purchase costs related to filter change-outs is to recommend a high-capacity pleated filter with an extended filter life that provides the desired filtration efficiency at the lowest possible airflow resistance.
  • Resistance to new technologies: It is important to remember that electret treatments are an enhancement of an underlying mechanical structure. The combination of different electret treatment patterns/charge distributions and different mechanical structures means that all electret-charged media filters are not the same. Filter manufacturers would be well-served to learn more about the differences among electret-treated media filters by speaking with their filter media supplier(s).

Regular filter changes are crucial for reducing HVAC system energy consumption.

Manufacturers working with channel partners that are not yet on board with the benefits of helping their customers achieve better IAQ should know this and share it with their customers: Providing superior IAQ can improve health, work performance and school performance, as well as reduce healthcare costs, and consequently can be a source of substantial economic benefit. Not only can it be an economic benefit for those who own, live and work in buildings with good IAQ, but it can also be a source of economic benefit for companies selling IAQ products and services.