Don’t forget the furnace filter

Don’t forget the furnace filter

Everything you need to know about furnace air filters

Most homeowners don’t really think about the furnace filter until something goes wrong. The furnace air filter is a critical component of any forced air HVAC system. There are different types, ratings, and sizes that offer varying benefits to your unit and your home.

With regular furnace filter maintenance, your heating and cooling system will continue to perform well all throughout the year. Here’s what you need to know about your furnace filter…

The facts about furnace air filters

They lower energy costs

The main purpose of a filter is to protect the blower fan from dust, hair, and debris that your return air ducts pull in. Your furnace has to work harder when your filter is dirty, using more energy to get the desired temperature you want in your home. Changing your filter every 1-3 months will help the furnace work efficiently and save you money on your annual utility costs.

They maintain healthy air quality

The furnace air filter removes contaminants from your HVAC system. A dirty furnace filter causes allergens, dust and dirt to circulate through your home and lessen the air quality. Quality indoor air is especially important for people with asthma and allergies.

They extend the life of your furnace

When dirt, dust, and grime accumulate on the filter, it’s much harder for air to pass through. In turn, the motor works harder and the system could overheat. This can lead to costly furnace repair or even replacement.

Older furnaces that haven’t had proper annual cleanings and maintenance are the most susceptible.

They have different ratings

Furnace filters are rated by a minimum efficiency reporting value (MERV). MERV rating ranges from 1 – 12. A higher rating filters more particles, but allows less air to flow and can force the system to work harder.

A rating of 8 – 11 is adequate for most homes. Some retail stores have their own rating and should be converted to the MERV scale to ensure the safety of your furnace. Check with your manufacturer to make sure you choose the best filter for your furnace.

They have different styles

Not all furnace filters are created equal. Made from a variety of materials with advantages and disadvantages based on the needs of your furnace, here are what homeowners have to choose from:

Electrostatic filters use self-charging fibers to attract particles from the air. Disposable or washable electrostatic filters can be purchased depending on the requirements of your furnace. Washable versions offer a MERV rating between 4 and 10, and last considerably longer than the average air filter. Maintenance on a washable filter requires soap and water to wash the filter and letting it completely dry before reinstalling it—to avoid the risk of mildew and mold growth.

Fiberglass (or synthetic) filters are a cost-effective option. They catch up to 80% of particles 50 microns and larger, and 25% of particles between 3 to 10 microns. Considered minimum protection, these filters prevent dust and dirt from building up on heat exchangers, fan motors, and other surfaces. They allow maximum airflow, but don’t filter harmful contaminants.

High efficiency particulate air (HEPA) filters provide furnaces with high-end filtration. They trap up to 99% of particles 0.3 microns or larger. Although they eliminate indoor pollutants and create a healthier environment in your home, they can drastically reduce your system’s airflow and cause a higher use of energy than other filters.

Pleated filters offer high-efficiency results. They trap particulates 0.3 micron in size, such as bacteria and viruses. Pleated filters are more efficient and last much longer when compared to fiberglass/synthetic filters; and they eliminate pollutants from the air without sacrificing airflow.

Polyester filters are made from high quality materials and median-sized. They trap and eliminate 80% to 95% of particles 5 microns or larger. Costing fours time more than the average fiberglass/synthetic filter, polyester filters offer more protection against pollutants that cause health issues.

They have a life expectancy

Most filters come with a recommended guideline that lets homeowners know how long air filters last, and when they should be changed. When you purchase a new filter, check the package for details.

The standard recommendation to change an air filter is every three months. Dirty, clogged air filters prevent healthy air flow, damage the components of your HVAC unit, and decrease its efficiency. Regardless of time, if you have a dirty air filter it needs to be replaced.

Set a monthly reminder to check or change your filter. It’s also important to have seasonal furnace maintenance completed by a certified professional HVAC technician—like us.

They vary in size

Furnace air filters come in many different sizes. It’s important to select a replacement filter that fits your unit’s filter cabinet correctly. Otherwise, airflow obstructions will hinder the performance of your furnace.


If you have questions, or need assistance with your furnace air filter, give us a call at 250.465.2490

We are happy to help you have the best in home comfort—always.

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