Our Most Popular Air Filters!

January 10, 2024

Our home comfort team and our customers at Save Home Heat Company often turn our attention to indoor air quality (IAQ) concerns as we enter the winter. Of course, more time is being spent indoors, with the house closed up tight. Accordingly, and in keeping with our current ‘IAQ season’ theme, in this post we’ll review the furnace filter upgrades that are currently most popular with our customers.

While some of this may sound familiar, we’ll be taking a closer look at impactful performance data and other details that enable us to recommend products that make the most sense for each family we visit – and are also the best fit for their specific home and system.

snow landscape with mountains and trees

Furnace Filter Upgrades Trending With Our Customers

Lennox Healthy Climate Solutions Logo

The most common furnace filter upgrades selected by our customers in the Denver-Boulder metro area currently are two products from the Healthy Climate Media Air Cleaner line from Lennox Industries: the HC11 Media Air Cleaner and the HC16 Carbon Clean 16 Media Air Cleaner.

But before we zero in on those two high quality air filters, we think it will be helpful to first discuss some important related factors.

An Option for Homes with Hot Water Heat, Too!

Our team would like to make sure to point out that homeowners who enjoy the benefits of a home heated by a central boiler and zoned hot water heat (baseboards, radiant floor, etc.) may want to keep in mind that highly effective, whole-home air filtration, air purification, and more can often be achieved even in their type of homes. We have had great success installing scaled-back ducting systems in homes that have hot water heating, for just this purpose. Think of an independent air recirculation system, dedicated to products such as the air cleaners discussed in this post, central steam humidifiers, air purifiers, and even fresh air ventilators (ERVs).

What Does MERV Mean?

The numbers following “HC” in the model number of both of these Lennox products indicate the filter’s MERV efficiency rating. MERV is an acronym for “Minimum Efficiency Reporting Value,” an air filter efficiency measurement that’s widely accepted in our industry. The higher the number, the more effective the filter.

Virtually all air filters are tested by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), per ASHRAE test Standard 52.2. Each filter is assigned a MERV efficiency rating based on its ability to effectively filter particles ranging from .3 to 10 microns in diameter. For quick reference, 1 micron is approximately 1/25,000th of an inch. Down in the .3 micron range, we’re talking about particles that cannot be seen with the naked eye.

One-Inch Standard Filters vs. Media Air Cleaners

Filter filtering
MERV efficiency ratings for 1-inch thick, disposable, fairly basic furnace filters typically range between MERV5 and MERV8. Somewhat acceptable, but not great. High efficiency media air cleaners, on the other hand, have efficiency ratings between MERV11 and MERV16, and in most cases are 5” thick.

In either case, the filter requires replacement on a regular basis. One-inch filters may need to be replaced as often as four times a year or more, while media air cleaners often go a year before needing replacement of the filter element. As always, the frequency that’s best for specific homes and families depends on a range of factors.

How Do MERV Ratings Affect Airflow & System Performance?

Lennox 'Air is Life. Make it perfect' logoThe higher the MERV rating (efficiency) of an air filter, the greater the pressure drop, or restriction to airflow thru the filter, and the more restriction to airflow it adds to a system. For this reason, the most efficient filter option isn’t always the best call for every home. Although a homeowner may initially be attracted to the more efficient HC16 Lennox filter, sometimes the HC11 is a better fit.

For example, if the ducting system in a home is marginal in its ability to deliver air evenly throughout the home (especially upstairs or at the end of the line), then an ‘ultra efficient’ furnace filter could make matters worse. Choosing the right filter in this type of situation is especially critical.

Let’s look a little closer at two related factors that play an important role in which filter is the better call.

CFM Ratings & Pressure Drop

Beyond the MERV efficiency rating, There are two other ratings to consider when determining which air filter is right for your home. The CFM rating and the pressure drop rating of the filter must also be considered.

CFM Ratings of Fans & Air Filters

CFM refers to “cubic feet per minute,” the unit of measurement used to compare the airflow capabilities of furnace and handler fans, and also ducting systems and furnace filters, too.
The higher the CFM rating, the more air is being moved – or in the case of filters and ducting, the more air that can be properly accommodated.

Pressure Drop in the System

When discussing pressure drop in a ducting system, the term “inches water column” (or inches WC) is a key unit used for measuring static pressure, or resistance to airflow. The greater its pressure drop rating, the more resistance to airflow a component contributes to the system. Pressure drop in a system is determined primarily by the nature of the ducting system, the furnace (or air handler), and the air filter. There are limits to how much pressure drop a system can accommodate without inviting a host of problems.

Without getting any deeper into the weeds, it’s critical to choose an air filter that doesn’t add excessive pressure drop to the system, and is the right match for the furnace fan’s CFM rating and the ducting system’s airflow capabilities.

How Do MERV Ratings Factor In?

In summary, if your ducting system and furnace are up to the job, the furnace filter option with the higher MERV rating is always an upgrade worth considering due to the more effective air filtration it provides. But as we always stress, the most efficient air filter isn’t always the best decision, it depends on the particulars of the home. Our estimating team looks closely at these particulars, and we install plenty of both the HC16 and the HC11 media air cleaners, as circumstances dictate.


Common Indoor Air Pollutants

Depending on the air quality issues we are asked to address, matching the particle sizes of indoor air pollutants with the MERV ratings and capabilities of the filters being considered often plays a significant role in the purchasing decision. Here’s a quick summary of common indoor pollutants and their particle size ranges:

Choosing a Lennox Filter in Boulder, CO - Save Home Heat
  • Household dust: .5-100 microns
  • Pollen: 5-1,000 microns
  • Pet dander: .5-10 microns
  • Tobacco smoke: .01-4 microns
  • Mold and mold spores: 3-40 microns
  • Bacteria: .3-60 microns
  • Viruses: .005-.3 microns

Compare the indoor pollutant particle sizes above with the performance data of the HC11 and the HC16 below, and you can start to determine which filter might be the best match to address your specific IAQ concerns.

Our Most Popular Furnace Filter Upgrades: The HC16 & HC11 from Lennox

Including the filter housing, both the HC11 and the HC16 media air cleaners from Lennox are approximately 7” wide, with a depth and height that varies depending on the size filter. The user-friendly, replaceable filter elements come in three sizes: 20”x20”x5” thick, 16”x25”x5”, and 20”x25”x5”.

Accommodating an airflow range of 800 to 2,000 CFM (2,000 CFM = 5 tons), both products are ideal for providing enhanced protection for your central AC system’s indoor cooling coil, as well as the secondary heat exchanger in high efficiency furnaces (both have fin tubing that are a magnet for dust). As with all media air cleaners, these products do not use electricity or produce any ozone.

Of note, most media air cleaners also carry efficiency ratings for the removal of other common particle sizes; this data can be found in more detailed manufacturer spec sheets. The cool part is that the larger the particle size, the more effectively these filters remove those particular pollutants!

Here’s some additional highlights and ratings of the Lennox HC11 and HC16 media air cleaners that help our team help our customers to the best of our ability:

HC11 Media Air Cleaner

The HC11 is an excellent furnace filter for reducing pollen, dust, pet dander, and certain bacteria and viruses. It’s a great step up from basic 1” filters and is the best media air cleaner choice for homes where airflow is a potential concern:

  • Initial pressure drop rating: .25-.27 inches WC, depending on model
  • 28% removal of particles .3 to 1.0 microns in size
  • 65% removal of particles 1.0 to 3.0 microns in size
  • 87% removal of particles 3.0 to 10.0 microns in size

HC16 Carbon Clean 16 Media Air Cleaner

With a MERV16 efficiency rating, the HC16 provides hospital-grade air filtration and is the most efficient in-line air filter available. This air cleaner is extremely effective at reducing airborne allergens, bacteria, viruses, and mold, as well as airborne dust, pollen, pet dander, and more:

  • Filter fibers are coated with activated carbon to assist in odor and ozone reduction
  • Initial pressure drop rating: .29-.31 inches WC, depending on model
  • 95% removal of particles .3 to 1.0 microns in size
  • 99% removal of particles 1.0 to 3.0 microns in size
  • 100% removal of particles 3.0 to 10.0 microns in size

HC11 vs. HC16: Our Takeaway

As you can see above, the HC16 is far more effective at removing smaller particles than the HC11 – in particular, substances such as smoke and a broader range of bacteria and viruses – making the HC16 a ‘healthier’ air filter choice. However, the HC16 is approximately 15% more restrictive to airflow than the HC11, which makes the HC11 a better choice for homes that have potential air delivery issues.

Ultimately, both air filters are a big step up from the 1-inch disposable filters many of us still use, when applied properly.

The HEPA Option

For even greater, state-of-the-art air filtration – with zero impact on airflow or system performance – we also offer HEPA air filtration systems from Lennox, which are a more costly option and require a little new ducting, as well. In the Boulder-Denver area, for more information on these ultimate air filtration systems, please reach out to our team.

Upgrading Your Furnace Filter in the Denver-Boulder Metro Area?

High efficiency media air cleaners are not for everyone, but these products continue to grow in popularity, and for good reason: Compared with standard options, they do a superior job of filtering the air you breathe indoors. When providing an installation quote, considerations such as airflow restrictions and ducting accommodations, along with pollutant priorities and filter efficiency, are among the important factors that we look at closely with our customers.

Save Home Heat is a Lennox Premier Dealer

To learn more or to schedule a free, highly informative, low-pressure installation quote for your Boulder-Denver area home, please reach out to our friendly, helpful team at Save Home Heat Company today!

Please contact me to schedule an IAQ upgrade quote!