Furnace Filters

Furnace filters can be a real pain in the bu**. To start with, they're down in the basement where they're both out of sight and out of mind so they're easy to forget. Then, when you finally do remember you should be checking your filter, you don't have a clean one so that means a trip the home or hardware store. Are furnace filters really worth the hassle? Can't you just leave them for a few months without worrying bout them? The answers are definitely yes - furnace filters are worth the hassle, and no - you don't want to just leave it for a few months. 

Furnace filters can save you money

The whole idea of a furnace filter is to take dust out of the air circulating in your house. Your furnace blower needs to work harder and stay on longer to circulate the air in your home when it has to push air through a clogged or plugged up filter. This extra work shortens the life of your blower as well as costing you money on your utility bill to pay for that power.  

But, it's more than just saving a few dollars

  • Dust isn't just some harmless powder that gets on your furniture and under your bed and looks messy. Household dust is actually a mixture of a whole bunch of things like dried skin (you dust factory you), pet dander, lint, and a whole bunch of fun things like mold and plant spores, bacteria and even dust mite droppings. Sounds wonderful doesn't it?
  • On top of that, most North Americans spend the majority of their time (some up to 90%) inside their houses. So most of the time the air we're breathing is full of dust. Even worse, in an effort to conserve energy and preserve the planet many of us have sealed up our homes so tightly that the inside air never gets out, and no fresh air gets in, so we're breathing the same air over and over again.

Just think about the impact breathing that dusty air day after day has on respiratory diseases like asthma, bronchitis and the flu and possibly, the ever increasing rates of allergies in children. Starting to see why furnace filters are a good idea? 

When it comes to furnace filters you have a few options  

  • Common standard furnace filters are made of spun fiberglass, cloth or open cell foam with a cardboard frame. They usually come in packs of three and cost about $1 each. These filter remove about 10% of the dust floating in the air (large particles only) and need to be changed frequently (manufacturers recommend monthly) if they are going to do any good.
  • Since they do trap more dust reusable/washable filters are a better option than the disposable filters. However, to be effective they need to be cleaned regularly and getting all that trapped dust out of them can be a challenge.
  • Pleated disposable filters are really a flat filter folded in a series of pleats so you end up with more surface area to catch dust particles. Since pleated filters usually have a denser filter element and a larger surface area than other disposables, they do work better (reportedly remove 30% to 40% of airborne particles). Pleated filters do cost more (about $5 to $10 each) but manufacturers claim they don't need to be replaced as often as flat filters (only about every two to four months).
  • High efficiency pleated filters are the best air filters you can use in your furnace. Their design uses electrostatically charged fibers to attract and hold dust, allergens and even tiny smoke particles. These electrostatic filters are much more effective than plain filters  - capturing up to 30 times the number or allergens than a plain filter (including small particles, not just the large, easy to trap ones). Electrostatic filters are obviously the most expensive furnace filters (they cost about $25) but such a good job of keeping the air in your house clean that a version of the electrostatic filter is endorsed by both the American and Canadian Lung Associations.


Maintaining your furnace filter  

The best way to tell if it's time to change your furnace filter is to actually make a trip down to your furnace once a month. Take the filter out and check to see if it's dirty, if it is - replace it, no matter how recently you last changed it. Remember, taking care of your furnace filter won't just save you some money in the long run, more importantly, it will help preserve your family's health and that's worth the price of a new furnace filter. 

Murray Anderson is an experienced freelance writer with numerous articles published on the web as well as in print magazines and newspapers in both the United States and Canada. He writes on a wide range of topics and is a regular contributor to DoItYourself.com.