Choose the Best Furnace Filters for Cleaner Air and a Healthy Family

Learn how to choose the best furnace filters for your home and family.
- sleep more soundly
- work better
- study more effectively
- be more creative
- stay healthier
- have more energy
- and reduce the amount of housework. With a well functioning filter there is no need to clean draperies, upholstery, windows and walls quite so often.

Why a filter? Because...

The air in our homes, offices and schools is polluted. Our lungs struggle daily against contaminants that can lead to headaches, dizziness and digestive problems - even some chronic and acute diseases.

Improving the quality of the air we breathe is no longer an option. Although we don't consider our home environments polluted, the US Environmental Protection Agency does. They have warned that indoor pollution can be two to five times higher than outside.

This means that the EPA considers poor indoor air quality to be one of the top 5 risk factors to public health. Because we spend 90% of our lives inside, we are at risk and need to find a solution.

More than one third of adults and children have allergies, asthma or respiratory distress. Some types of furnace air filters are designed to improve the quality of indoor air while others are only meant to protect the furnace.

The best furnace air filters

When installed in a forced air heating or cooling system, a filter can significantly improve the indoor environment - because it acts as a whole house air cleaner. Cleaning or changing a furnace air filter is one of the easiest ways to prolong the life of your heating system and to keep it operating its best.

Install the right kind of furnace air cleaner Disposable fiberglass filters are the least expensive, but the least effective option. They are designed to provide minimum protection for the furnace itself and are not intended for filtering or cleaning. Pollen and mold pass right through.

Electrostatic filters

A passive electrostatic furnace filter has a static charge that attracts dust, dirt and other matter. It can rid the house of large and small particles (to 1.5 microns) without the production of ozone. Although slightly better than fiberglass, it still blocks just 15 to 20 percent of airborne particles.

If respiratory problems and allergies aren't a concern for your family, a disposable or reusable filter can be enough to keep the furnace working well. But it's essential to clean or change the filter every month - half of repair calls are caused by dirt and dust.

A pleated filter is a low cost option to reduce allergens and keep your home cleaner. It is made from a much denser mesh material that increases surface area and traps mold and pollen. Most are 35 to 50 percent efficient.

Filters 1-2" deep will fit in the filter rack of many furnaces. Although thicker filters are more effective, modifications must be made to the duct system to accommodate the larger size.

Electronic filters

An electronic air filter is helpful for removing harmful pollutants. Improve the environment for those who suffer from allergies and asthma by eliminating pollen, mold spores and up to 94% of smaller particles.

A furnace electronic air cleaner is made to fit in the existing slot. Plug it in and it creates an electrical field that magnetizes pollutants so they collect on the filter material. Some units also use a panel-type prefilter along with a carbon filter.

Replacement media and humidifier pads are quite affordable – they cost less than $5 a month. Electronic furnace filters are easy on electricity bills using only as much energy as it takes to ring a doorbell.

Rid airborne viruses for a healthier family

Consider a top-of-the-line HEPA filter for a furnace. They are used in hospitals, electronics manufacturing and research facilities where clean air is crucial. By definition HEPA filters must be capable of capturing 99.97% of particles as small as .3 microns - or 1/100th the width of a human hair.

There is greater resistance which means a larger blower is needed to keep air circulating freely. Look for a HEPA furnace filter with a built in blower or motor that can handle the pressure drop.

Unless family members are extremely sensitive to environmental contaminants, a HEPA filter for the furnace may not be necessary.

Whatever the type, look for a filter that allows air to circulate freely. Airflow that is less restrictive leads to a low pressure drop so the furnace spends less effort and energy heating the house.

Some manufacturers offer units with antibacterial agents that work to limit and control bacteria, fungi, mites, and germs as well as to reduce unpleasant odors. Warranties range from 5 years to lifetime.

The filter industry divides filters into three categories determined by dust spot efficiency
- low-efficiency filters are less than 30%. The typical furnace filter is below 10%.
- medium-efficiency - between 30 and 50%.
- high-efficiency - between 50 and 95%.

Keep the furnace fan running

Whichever type of furnace filter you choose, it will work best if the blower fan runs continuously. If the fan is set to "auto" it is running only 20 percent of the time. That means the filter will trap only a small percentage of the particles it’s designed for.

Popular brands include 3M, Trion, Honeywell and Lennox.

Running a furnace will dry the air - keep healthier with humidifiers and filters.