Air Filters Do Double Duty

The air filter in your heating and cooling system works quietly to remove dirt and debris from the air as it passes through your system.  This not only reduces the amount of airborne contaminants in your home and improves your indoor air quality, but it also protects your expensive heating and cooling system.  By removing dust, dirt, and debris from the air, your air filter keeps your evaporator coil and other components free of contaminants.  When a layer of dust and grime accumulates on your evaporator coil, heat transfer efficiency is reduced and as a result, your HVAC system operating efficiency is reduced.

It is critical for peak heating and cooling performance to change your air filter regularly.  A clogged air filter makes the system work harder and shortens its lifespan.  Experts recommend changing the air filter every two to three months.  During periods of heavy usage, the air filter should be changed more often. Changing the air filter is an important part of regular HVAC system maintenance.

There are several different types of furnace filters readily available at your local home improvement center.  Standard fiberglass filters are inexpensive, but only catch larger particles of dirt, dust, pet hair, and lint.  A pleated filter is a better option.  These cost a little more, but they are much better at capturing smaller airborne particles.  Since pleated filters capture more dirt and debris, they need to be changed more frequently as they will clog sooner than a standard filter.

When buying a new furnace filter, look for a medium efficiency filter that is the right size for your HVAC system.  Filters with a very high efficiency rating can reduce the air flow through your system causing a drop in efficiency.

Why Is Changing Your Furnace Filter So Important?

Any heating professional will tell you to faithfully change your furnace’s air filter on a regular schedule, all year round. If you look up heating or furnace maintenance advice, changing your furnace filters often will inevitably be on the list. Why is this small task given such importance? 

Many people have the mistaken impression that furnace filters are intended to filter the air coming from the furnace into the home. In actuality, the furnace filter’s primary purpose is to protect the furnace by filter the air that comes into the furnace. When you wait too long in between filter changes, the filters begin to get clogged with particles they have trapped from the air. The more particles that are trapped in your filter, the more difficult it is for air to flow through the filter. It is this obstruction of airflow that you want to avoid. 

When airflow is restricted by a dirty furnace filter, your furnace has work harder. This means that the life of your furnace may be decreased and service calls may be more frequent, all because you didn’t change your inexpensive furnace filter as often as you should.

When choosing a furnace filter, you might assume that a more expensive furnace filter does not need to be changed as often as a less expensive one. In reality, the opposite can be true. Some furnace filters which advertise their ability to trap minute particles are more dense than the standard furnace filters. This means that these filters can also become clogged faster than your standard filters and should be changed more frequently, not less frequently. 

Protect your furnace and lengthen its life by frequent changes of the furnace filter.

Change Your Air Filter For More Efficient Cooling

As we move into the dog days of summer, don’t forget to change the air filter on your central air conditioning or heat pump system.  If you have central air conditioner combined with a forced air furnace, it’s easy to forget about the filter in the summer because we often call it a “furnace filter”, but your central air conditioning system uses the same filter.  Likewise, a heat pump uses the same filter whether it’s in heating or cooling mode.

Changing or cleaning the air filter regularly can help your system work more efficiently, increase your comfort, and save you money on energy bills.  Your system was designed to operate efficiently with a  certain level of air flow across the coils.  When the air filter gets clogged with dust, dirt, pet hair, and other debris, it reduces the air flow which makes your system work harder to maintain the selected temperature.

According to EPA estimates, changing or cleaning a dirty air filter can reduce your energy usage for cooling by as much as 15%.  In addition, the air filter protects the coils from dirt and debris.  If dirt, dust, and debris are allowed to accumulate on the coils, it acts like an insulating blanket and prevents the coil from working efficiently.

Changing or cleaning your air filter monthly will not only lower your energy bills today, but it will also help extend the life of your heating and air conditioning system.  You can buy new air filters in a wide variety of sizes at your local home improvement store.  Be sure to write down the size of your old filter before you go so you can be sure to get the right size.  The size should be written on the edge of your old filter.

High Efficiency Furnace Filters

Forced air heating and cooling systems such as a heat pump or a central air conditioning system combined with a furnace are equipped with a furnace filter or air filter to reduce airborne contaminants and to help keep the heat exchanger and coil free of dust, dirt and debris.  Most homeowners know to change the filter regularly, but you can improve indoor air quality and provide an added measure of protection for your system by upgrading to a high efficiency furnace filter.

The standard blue fiberglass filters that most HVAC systems are equipped with do a good job of collecting large particles of dust and hair, but a lot of smaller particle easily pass through these filters.  Medium and high efficiency filters do a much better job of capturing smaller airborne particles.  These filters are pleated and can be purchased through your HVAC contractor or at your local home improvement center.

Furnace filters are rated based on their ability to capture small particles.  The higher the minimum efficiency reporting value (MERV), the better job the filter will do in capturing small particles.  Standard filters have very low MERV ratings, but pleated filters are made with a  range of MERV ratings from medium efficiency to ultra-high efficiency.  Before you rush out and buy the filter with the highest MERV rating you can find, keep in mind that these filters also restrict air flow.

Filter manufacturers claim that the airflow restriction is not significant, but an older system could be negatively affected by installation of an air filter with a very high MERV rating.  Try using a medium efficiency filter first.  If your system can move air through a medium efficiency filter without a problem, then you could consider a further upgrade.  Remember to check the filter frequently and change it whenever it gets dirty.

Changing Furnace Filters

Your furnace filter (or air filter if you have a heat pump) does double duty:  it helps improve indoor air quality by reducing the dust, dander and debris in the air, but more importantly it keeps the heat exchanger and coil clean.  A dirty heat exchanger or coil will reduce the efficiency and decrease the life of your heating and air conditioning system.

A dirty air filter will also reduce the efficiency of your system and lead to premature breakdowns.  A clogged furnace filter restricts air flow which makes the system work harder and less efficiently. Changing your furnace filter regularly will help keep your central air conditioner, forced air furnace or heat pump in top operating condition.

How often do you need to to change your furnace filter?  The short answer is to change the filter whenever it gets dirty which can vary greatly depending on how often your system has been running, whether you have pets, and other things. As a general rule, a standard fiberglass furnace filter should be changed every one to two months during the heating and cooling seasons.  A pleated or high efficiency filter will capture more dust and dirt particles and should be changed a little more frequently.

Your HVAC technician will replace the furnace filter during your scheduled spring and fall service visits, but you will need to change the filter between service visits.  Changing the furnace filter is a job that almost every homeowner can handle.  If you have never changed the filter, ask your HVAC technician to show you how to do it during your next service visit.

Furnace filters come in many different sizes so write down the size for your system and buy half a dozen air filters next time you are at your local home improvement center.  That way you will be sure to have one on hand when you need it.