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Indoor air pollution is an inescapable reality in every Florida home. Simple day-to-day tasks generate pollution, from cooking and cleaning to showering and even breathing. The tighter your home is built, the higher indoor pollution levels can become. The best way to counter poor indoor air quality is to trap the contaminants and prevent them for circulating around your home.

Various air cleaning techniques exist today, but one of the most basic options is simply to install air filters in the HVAC system. Most Florida homes today have forced air heating and cooling, making this a viable option for improving indoor air quality all year-round.

How do you choose the right air filter for your HVAC system? Dozens of options exist today with varying levels of efficiency. Should you make your decision based on cost, efficiency or the ability to maintain airflow? Actually, the key is to find air filters that accomplish a good balance between all three of these requirements. But first, consider the importance of maintaining a clean HVAC air filter.

Change Your Air Filter Regularly

In the case of air filters, “regularly” means checking the filter monthly and changing it after no longer than three months, unless the instructions on your individual air filter says different. The following problems with dirty air filters should encourage you to make changing the air filter a priority.

  • Dirty air filters lead to early system failure. Dirty filters block airflow, which puts extra strain on the fan motor. Over time, the motor may burn out and overheat the system, leading to premature failure.
  • Dirty air filters increase energy consumption. An over-worked fan motor consumes more energy than one with adequate airflow passing through the system.
  • Dirty air filters increase energy bills. Changing the filter is an investment, but it’s one that pays for itself through increased energy savings.
  • Dirty air filters reduce indoor air quality. A clogged filter can’t trap any more contaminants, and particles start making their way through. If you have sensitive individuals living in your home, this can cause additional allergies and increased asthma symptoms.
  • Dirty air filters increase your carbon footprint. By reducing your home’s energy consumption by helping to maintain adequate airflow in the HVAC system, you take one step toward a healthier environment.

MERV Ratings

Now that you’re convinced of the importance of changing air filters regularly, you need to understand which filter suits your home best. All filters earn a Minimum Efficiency Reporting Value, or MERV rating. This is the industry standard for measuring air filter effectiveness. The higher a filter is rated on the MERV scale, the more effective it is, meaning it can trap a higher number of smaller particles.

Understand how air filters with different MERV ratings work and you’ll learn why medium-efficiency filters are the best options for most residential HVAC systems.

The MERV scale ranges from 1 to 16 with HEPA, or High Efficiency Particulate Air filters, ranging from MERV 17 to 20. Within the standard MERV 1 to 16 scale, filters are divided into three broad categories:

  • MERV 1-6, low-efficiency filters: These are usually rectangular, one-inch thick fiberglass filters. They remove less than 10 percent of the particles passing through them. Most of the particles that become trapped are easily seen by the naked eye, such as carpet and textile fibers, pollen, and dust mites larger than 10.0 microns. (One micron is 1 millionth of a meter.) Low-efficiency filters come standard on HVAC equipment to protect the system from large dust particles. They have little if any effect on indoor air quality.
  • MERV 7-13, medium-efficiency filters: These are typically pleated filters of a woven material. They remove about 30 to 50 percent of particles down to 1.0 microns, such as milled flour, auto emissions, hair spray and mold spores. These filters provide superior residential air filtering capabilities that improve indoor air quality without blocking airflow as long as they are changed regularly. Both washable and disposable options are available.
  • MERV 14-16, high-efficiency filters: These filters greatly resemble medium-efficiency filters, but they can trap even more particles. With a higher cost and greater efficiency than low- and medium-efficiency options, filters in the MERV 14 to 16 range can trap a majority of particles down to 0.3 microns, including all types of bacteria, viruses and carbon dust. Because they restrict airflow so profoundly, however, filters in this range are not recommended for residential use. Instead, they are reserved for hospitals and smoking lounges where more filtration is necessary.

Effectiveness of HEPA Filters

HEPA filters are rated higher on the MERV scale than ordinary filters. They range from MERV 17 to 20 and have a minimum efficiency rating of 99.97 percent, capturing particles smaller than 0.3 microns. HEPA filters with the MERV 20 rating, the highest possible rating for an air filter, are 99.999 percent effective at trapping even the smallest airborne particles. These incredibly efficient filters are sometimes used in vacuum cleaners and air purifiers as well as in cleanrooms and around radioactive and carcinogenic materials.

The Environmental Protection Agency (EPA) warns that using a filter with a very high efficiency rating in a residential HVAC system is not cost effective. The reason is that super-efficient filters block airflow profoundly, which can raise energy bills or even damage your HVAC equipment. So while it may be tempting to invest in the most efficient filter on the market today for the cleanest indoor air possible, air filters between MERV 7 and 13 are nearly as effective as true HEPA filters and don’t pose a problem with blocked airflow.

Limitations of HEPA filters

The incredible efficiency of true HEPA filters should only be used residentially in vacuums and portable air purifiers. These devices are designed with higher airflow capabilities to overcome these filters’ dense weaves. Still, HEPA air purifiers have their limitations. For example:

  • HEPA filters only trap particles, not gaseous fumes. Many high-end air purifiers combine a HEPA filter with another air-cleaning system, such as a carbon filter, to target and remove gases from the air.
  • HEPA filters are more expensive. Even in air purifiers that don’t need frequent replacement, HEPA filters still need to be checked and replaced once or twice per year. That means there’s a recurring cost to running an air purifier in addition to the initial purchase price. Of course, if you or someone in your home suffers from severe allergies, the price could certainly be worth the cleaner indoor air you enjoy every day.

Choosing the Right Air Filter

The trick to cleaner indoor air quality without damaging the HVAC system is to install an air filter that corresponds with the system’s recommendations. If you’re not sure what the recommendations are with your system, contact an HVAC company for help.

It’s worth the effort to get this right. After all, a filter with a lower rating than your system’s recommendations prevents you from enjoying the cleanest indoor air possible. Then again, a filter that’s rated too high could damage your system and lead to expensive repair costs.

In most homes, the magic number lies somewhere between MERV 7 and 13. This medium-efficiency range removes more particles than low-efficiency filters without creating the restricted airflow of using high-efficiency air filters. Keep in mind that HVAC contractors can boost your system’s fan speed to help overcome the restricted airflow of more efficient filters, but this increases energy costs.

If someone in your home has severe allergies, consider installing a portable air purifier with a HEPA filter in their bedroom. This room generates plenty of dust, textile fibers, bacteria, viruses, dust mites and other contaminants for the purifier to trap. It’s the room you’re bound to spend the most time in during a 24-hour period, so it’s the best place for a portable air purifier to do its job.

For additional help selecting the best air filters for your Florida home, please contact the professionals at Aqua Plumbing & Air. We’re the most trusted name in HVAC services in the Sarasota and Bradenton area. With experience dating back to 1974, you can count on us to provide objective advice and professional services.