By Colleen Rothe

The trees’ leaves are bursting with fall color and we’re awash in brisk morning weather. For those of us at higher elevations or latitudes, it’s time (if not a bit late) to prep for winter.

As a frugal consumer (or at least I try to be), I try really hard to not turn on my furnace until Oct. 15, at the earliest I was able to do that this year. Now if I can turn it off by March 15, I’ll be even happier. It saves on my electricity bill.

Before turning on your furnace, replacing the filter will help run your furnace more efficiently and keep all the dust and gunk which settled into your furnace and air ducts from being blown right into your home.

But this little overlooked part of maintenance to the furnace can make and break your home-heating bills. Filters protect the furnace and the fan. For those of us with allergies, keeping our furnace filters changed regularly helps reduce the particles that affect our health. A fine-tuned furnace increases the air-quality of your home and costs less to operate.

To understand why this little piece of maintenance equipment is so important, you need to understand how a filter works. When your furnace (or central air system) is on, especially when the fan kicks on, the filter of your furnace captures particles in two ways: mechanically and electrostatically. All filters perform mechanical filtration by providing a barrier that captures the “dirt” (aka nasty air particles) via the air passing through the filter. New allergen filters provide an additional electrostatic element, capturing up to 90 percent more particles (especially those that can make sensitive folks like me sneeze during the winter) like pollen, mold, dust mites and even pet dander.

Your filter is most effective when it is new and clean. As particles build up, and it is covered up with captured allergens – it’s time to change it. To know what type and size of filter you need, just remove the old filter. Typically it’s an easy-to-spot location. Be sure to note how the filter was inserted before removing it. Unless you really cheap out and buy the $1 filter, there are arrows that mark which end is up. Sometimes you can even just take the old filter with you to the hardware or department store to figure out which kind you need.

Home-heating industry experts say to change your household filter regularly. When it’s running 24-7, like in the winter months, it should be changed quarterly. But you may need to do it more – like monthly – if you have indoor pets, use a wood-burning stove or fireplace, regularly burn candles, smoke inside the home, or there’s any kind of construction work going on in the home. All of these conditions significantly add particles to the air. This will cause the filter to capture more particles than usual, shortening its life to less than the standard three months, therefore reducing its effectiveness to capture the particles.

The effectiveness of your filter’s capture ability depends upon the kind you get. There are washable filters, which environmentally seems really smart. But, the home-heating industry really can’t stand behind it because the technology is not there yet to provide effective filtration. Besides the energy it takes to wash the filter is hardly worth it as well. I mentioned the $1 filter above (with inflation they may be more like $3 a filter now). Bottom line is they are the lowest end, cheapest kind you can get. They are made of fiberglass, which is frowned upon environmentally speaking. Additionally, in the case of this filter, you get what you pay for and then some. If you hardly turn on your furnace, they may be worth it. But, for most Americans, we have our furnace on for at least four months out of the year. You’d have to change the filter of this low-end-kind about 16 times during those four months – yes, weekly – to get efficient use of filtration and keep your furnace running smoothly.

There are pleated three-month filters, which do not have electrostatic filter capabilities. They are little more than the fiberglass or washable filters, but in consumer trials, really don’t last the 90 days they claim – even without stressing conditions in the home like pets and candle burning.

The 3M Company makes a slightly costlier variety – the Filtrete™ Filter – but it lasts longer and provides better filtration because it provides the electrostatic-charged fibers to help reduce allergens blown through the furnace. It is recommended by the American Lung Association as meeting the association’s healthy house air quality guidelines. For the money and quality, it’s my choice, always. Keep in mind, I have allergies, own a dog, have a wood-burning stove I love to use in the winter (so I can keep the thermostat down low), and regularly burn candles. But you need to figure out what’s best for your situation.

One trick when you first start up the furnace for the winter season is to have two new filters handy. Put one of the new filters in, then run the fan continuously during the coldest part of the day (typically the early morning hours) for an hour to a few hours. Running it for a few hours is recommended if you have any of the above “stressing” conditions in your home. This will help clean out the ducts and furnace. Then turn the continuous fan off, and replace the filter again. I can tell you, you will be surprised at the amount of dirt collected by the furnace during this process. Then put the new furnace filter in.

A furnace is not a toaster (although truly that appliance requires maintenance, too). It’s the number one drain on your energy consumption. Simply keeping the filter clean and changed regularly goes the distance to keep your power bill lower and the air in your house cleaner. When was the last time you changed your furnace filter?