Furnace Filters and Maintenance

Most everyone I know ignores their furnace. It just seems to be one of those things that no one wants to deal with. But, with just a little bit of attention, you can keep your furnace and your house air healthy.

For most home furnaces up to 10 years in age, cleaning and inspection by a professional is required only every 2 years. After 10 years, you should have your furnace inspected and cleaned once a year. Of course, technicians will recommend servicing every year from day one. It can't hurt, but it is an unnecessary expense.

Furnace filters should be replace when they are dirty, not ever XX months. There are two major furnace filter types-mechanical and electronic.

Mechanical Type Filters

Mechanical filters range between 1 and 5 inches in thickness. They provide a physical barrier to airborne particles. The finer the "holes" the smaller the particles that will be trapped. The furnace should not be operated without filter(s) in place (some furnaces require more than one filter). Make certain that the filter is installed correctly. The direction of placement is indicated by an air flow arrow located on the outer "rim" for the filter. The arrow should be pointed in the direction of the air flow.

Some Lennox furnaces use a basket type fiberglass filter which sets in a wire frame. The frame itself is not a filter. Don't operate this type of furnace without the fiberglass media installed.

With filters, generally you get what you pay for. Cheap filters can collapse and be sucked into the blower/fan compartment. Cheap filters will only filter the largest of airborne filters. Cheap filters usually need to be replaced more frequently. Persons with allergies will get no relief from the use of cheap filters. Filters range in price from <$1 to $35.

I use a Skuttle High Efficiency filter. It is 5" thick and each filter runs about $26 (I buy them online). We replace our filter every 3 to 6 months. We do not have pets, and this can make a big difference in how long a filter will last.

TIP #1
Our thermostat fan setting is always set to "ON"...not AUTO. If you set your fan to the "ON" position you can enjoy a much reduced level of dust in your home and on your furniture surfaces. The air is continually filtered and is never allowed to settle. Your home will also have a more consistent temperature throughout. If someone in your home has allergies, the severity of their reaction to dust particles will be reduced because the air is super filtered. And, believe it or not, your blower will last longer-yes, longer. Starting and stopping your blower is harder on it than running it constantly. We never turn our blower off (throughout the year).

Tip #2
Don't try to clean a dirty filter, even with compressed air. Break out your wallet and buy a new filter.

Electronic Type

Some (manufacturers?) claim that electronic filters are more efficient (than mechanical). I don't think that they are any more efficient than a well maintained high efficiency mechanical filter. Electronic filters consist of a metal cabinet, a removable air cleaner unit, 120V electrical connection, and a switch. Dust particles drawn across the wires or plates are attracted to the electrically charged surfaces where the particles remain until the air cleaner unit is cleaned. When removing the unit for cleaning, make sure that the power is OFF. Do not stick your hand into the unit. Wait 30 seconds before sliding the unit out of the cabinet. This allows the residual charge to dissipate. Be very careful when handling the unit(s). The units consist of very fine wires and are delicate. They can be easily broken and may be sharp. Clean the unit per the manufacturer's instructions. I know of homeowners who run the units through a cycle in their dishwasher, but I can't vouch for this method.

Tip #3
Change dirty filters. Dirty filters restrict airflow, reduce comfort, increase operating costs, can ice up air conditioning coils, and overheat the heat exchanger. Keeping your filter clean is your first and most significant defense against damage and wear and tear on your furnace.