The Prairie Spy

Alan “Lindy” Linda

This isn’t a column for everyone; it’s about air filters. Air filters bring with them very little humor, well, except for the times new home owners—some of whom had been in their home for a couple of years or more—have proudly shown me their furnace. Those were humorous.

More than once, as they were proudly showing me the furnace, I have pulled the cover on the air filter housing, removed something that was so dirty that it looked more like a carpet than a filter,, and had the home owner say: “What is that?” Now that, you have to admit, is funny.

Unless you’re the furnace. The thing is, new home owners mostly just don’t know much, and as most humans do, they learn things the hard way.

When people buy their first homes, they don’t buy information, more times than not. They’re not alone. I  rentals, and air filters are the hardest thing for them to pay attention to. I can buy filters by the dozens, pile them up by the furnace, and there they sit. Unused. The old ones becoming carpets of dust, cat hair, dog hair, people hair, etc.

There are basically two types of commonly used air filters. One is the spun Fiberglas type. As you look at it, you can see right through it. Unless you know what I’m about to tell you, that semi-transparency tends to make you think that they’re no good; that they cannot stop much of anything. So they immediately buy the next type, the pleated paper kind.

The spun Fiberglas air filter works because of two things. First, as air races over those spun filaments, it creates static electricity, which builds up on those “strings” you’re looking at. Because of that electrical charge, dust particles are attracted to those strings, and stick there.

They are helped to stick there by the second reason these filters work well, because those filament strings are coated with a sticky substance, which helps hold the dust. Unfortunately, once those strings are coated with dust—and this coating is so fine that the human eye cannot see it—then the static part of this operation doesn’t work anymore. Now you have something more akin to a sieve, which it’s easy to imagine isn’t that good an air filter.

So you have to change this kind of filter on a time basis, because you cannot see when it is no longer functioning properly. Once a month. If you have air conditioning, once a month all year long.

The other kind of filter, the pleated paper filter, costs more money. Why, you might ask, does it cost more money? Well, one might speculate that it costs more money because it stops more dust, which it does, right from the time you install it. This type of filter is a kind of sieve, with very, very tiny holes in it. Those tiny holes stop tiny dust particles.

They stop particles so well that many HVAC installers have warned home owners that using this type of filter will void the warranty on the heat exchanger in the furnace. Why would we do that? Because home owners don’t change their air filters. Air can still get through a reasonably dirty spun Fiberglas air filter, but it cannot get through a reasonably dirty pleated paper filter. That causes the insides of a furnace to overheat, which in turn cracks the heat exchanger.

So I used to tell people this: You paid more for that pleated paper filter because it’s a better filter, right? You paid somewhere between five and ten times more for it, matter of fact. Therefore, logic tells you that it stops more dust, right? Further logic thus tells you that it must stop five to ten times more dust, right? (Well, if not, why are you buying it?)

Well, then, how can you logically deny that you have to change it five to ten times more often???

I said there was little humor in air filters. I kind of forgot that the look on home owner’s faces when I laid this sarcastic logic on them was kind of humorous. Wasted humor. Mostly, it didn’t do any good.

Change your air filter. You cannot change it too much. You can change it not enough.

More logic that doesn’t work.