“I think it’s somewhere over there,” I said, leading the way through the laundry room.

Like vines and overgrown brush, the criss-crossing clotheslines, baskets and boxes partially blocked our way.

We ducked between one of Bonnie’s sweatshirts and a pair of Julie’s pants that were hanging on a line.

Then I moved back a green laundry basket that had my son’s crumpled black suit in it — the one Matt wore two years ago to his high school graduation, which got soaked on the way home when he jumped into the Chi Omega fountain.

I pushed aside a pile of crusty, muddy clothes Katy wore last spring to Lawrence High’s mud volleyball extravaganza.

“Here it is,” I said, pushing aside some boxes.

The woman who had come to do routine maintenance on our furnace didn’t seem annoyed at all by the clutter.

She pulled out a small flashlight, popped off the front cover of the furnace and started checking things.

Then she slid out the metal sleeve that covers the furnace filter.

“Do you change your filter often? You should change it once a month, you know,” she told me.

Uh, oh.

I thought back, trying to remember when I last changed a filter. I think Clinton was still president.

“Not too long ago,” I said.

She pulled out a thin, gray fuzzy thing that nearly fell apart and was dropping clumps of dust on the floor.

“This hasn’t been changed since we were here six months ago,” she said. “I know because this is one of ours.”

She had me dead to rights.

“Those 16-by-25-by-1 filters are easy to find,” she said.

She told me if I didn’t change them more often, the dirt and dust would continue to build up inside the blades of the blower fans as well as other crucial parts of the furnace and air conditioning system.

Looking at the fuzzy gray, dusty filter, I wondered if there were any new, high-tech filters on the market.

Besides keeping the insides of the furnace cleaner, I’m sure it would make our air a little more breathable. And maybe I could get by with changing it less often.

Static electricity

A Web page that said “Furnace Filter Never Needs Replacement” drew me to look into one made by Air-Care Equipment (www.air-care.com).

The Electra Silver Model ES-8200 promised, “The Woven Polypropylene layer with integral antimicrobial material provides eight times more filtration than a disposable filter. The nonwoven polyester pre-filter will maintain high arrestance even when soiled.”

It already sounded like less work.

As air flows through the filter, an electrostatic charge is generated, which pulls in the dust like a magnet. The dust is released when you wash out the filter with a hose.

After doing more research, I found electrostatic filters are about three to four times as efficient as the standard throw-away fiberglass models. And they’re sturdier than the fiberglass, usually featuring aluminum frames.

There are several different brands, but they all work the same way. Expect to pay $100 to $180 for these permanent filters, compared with about $2 or so for a fiberglass model.

Pleated surfaces

Another type of filter that goes beyond the fiberglass filter are those with pleats. Because they have more surface area, they can collect more dust as the air flows through the surface. They run about $4 each.

You can also get high-efficiency pleated furnace filters, which help to capture the tiniest of the particles flowing through the air.

Among those on the market are 3M’s Filtrete filters (www.3m.com/intl/ca/english/centres/home_leisure/filtrete).

Those filters capture 90 percent of the large allergens, such as mold spores and pet dander. Most of the dust particles you see floating in the air are 1 micron in diameter or lower. Filtrete’s top filters pick up microscopic allergens down to 0.3 microns, such as dust, smoke and smog particles.

WEB Product’s Hepa-Pure filters claim their high-performance filters capture 99.97 percent of airborne particles 5 microns and larger.

These high-performance pleated filters, which also create an electrostatic charge, last about three months and cost between $10 and $30.

I ran across another type of filter, called the Air Sponge filter, (www.dustless.com/alpha/filters_orig.htm) which claims to be able to remove six times as many particles from the air as a typical electrostatic filter.

Electronic filters

You also can buy filters that use a voltage passing through the filter to help capture tiny particles. One such filter is the EnviroSept Vent Duct air cleaner, which pops into the same place your throw-away filter goes.

It uses a patented system that collects particles in the air that passes through it down to 0.001 microns.

The filter generates a 7,000-volt DC charge from its power head onto a central grid. That charge polarizes two separate half-inch thick polywool blended collector pads that sandwich the grid. Those pads are kept in place by the two outer screens, which are grounded.

Unlike some electronic filters, the EnviroSept doesn’t produce ozone.

A downside is the pads have to be replaced every one to two months. And the system is expensive. It costs $389, including 14 pads.

Filtering the junk

“You really should change those filters more often,” the woman told me again after she replaced the old furnace filter.

As I helped her find her way out of the basement and laundry room, I kept moving aside old boxes and baskets of clothes, old toys and clothes that nobody has worn for a while.

It hit me that our basement seemed to be like a filter, catching many of the things that passed through the household.

I tried to remember the last time I cleaned it out. It wasn’t too long ago.

I’m guessing it was sometime during the Clinton administration.