Neglecting to change certain filters can result in health problems. (mphillips007/Getty Images/iStockphoto)

One humid morning last summer, our faithful basement dehumidifier just wouldn’t turn on. I dug out the instruction booklet. Under troubleshooting tips, it said to check the filter, which should be “cleaned off and rinsed” every one to two weeks.

Filter? What filter? We had owned the unit for three years and never even realized it had one. I located the filter and gingerly pulled it out of its slot. The mesh and plastic filter was a thick blanket of dust and cat hair. We had choked our dehumidifier to death.

There are lots of hard-working things in our homes equipped with filters that trap dust balls, pollen and many other impurities. Some filters, such as those in dehumidifiers and dryers, are reusable and must be cleared regularly; others, such as refrigerator and HVAC, are disposable and need to be replaced on a regular basis. But with our hectic lives, changing a filter can get pushed to the bottom of a jammed to-do list. This can result in costly and unhealthy consequences.

In certain home systems, filters are essential to keeping air circulating. “You must keep airflow moving. It’s as important as changing the oil in your car,” says home expert Mike Holmes of DIY Network’s “Holmes on Holmes” series. “Imagine I wore a dust mask and did demo all day long with debris and dust in the air,” Holmes says. “It will plug that mask, and I’ll have trouble breathing. Your furnace is like your second set of lungs in your home. If you don’t change the filter often, you will tend to have a breathing problem within your system.”

Neglecting HVAC filters can increase your power bill or strain your system and damage it, says Cartier Kirby, customer experience manager at online filter store Filters Fast. “It can also impact indoor air quality and can affect people with allergies or asthma.”

Kirby says consumers should not try to save money by reusing disposable filters. “We’ve had customers vacuum their disposable furnace filter and put it back in,” Kirby says. “They don’t understand that used filters still have super-small particles embedded in them. You can’t vacuum those out and reuse.”

Holmes advises consumers to keep all instruction booklets. “Never throw out any directions. If you buy a new product, sit down and read the manual,” he says. As for remembering to change filters, he says: “Set up alerts on your calendar. If we can get alerts about birthdays, we can get them about cleaning our filters.”

Here are six common places you’ll find filters in your home. How many of them have you checked lately?

Coffeemaker

Coffeemaker charcoal filters often go unnoticed. Says Kirby: “They are so small you forget about them. In the morning when you’re making coffee, you aren’t thinking about maintaining the equipment.” Kirby suggests replacing them about every 60 days, or after 60 uses, for better-tasting coffee. “It also will increase the life of your coffeemaker because it reduces buildup of minerals and scale,” Kirby says.

Dryer

The plastic and mesh pullout lint catcher in your dryer needs to be cleaned after every load. Not doing this causes a potential fire hazard, Kirby says. Every once in a while, rinse the lint catcher under a faucet. If the screen in the lint catcher becomes ripped, order a new one. Even small holes will let lint get into the exhaust duct.

Furnace

A furnace filter is one of the most important house filters, ­especially if you own pets, smoke, or have asthma or allergies. The more often you replace it (usually every 30 to 90 days), the longer your furnace could last. Says Kirby: “If you don’t replace your filter as frequently as recommended, it becomes overwhelmed with dust and creates a strain. This might increase your power bill or worse, create irreparable damage to your system.”

Humidifier

Some HVAC systems have whole-house humidifiers that dispense moisture as you heat. Most come with disposable pads or filters that absorb mineral deposits and other impurities from water. Experts say these should be replaced once or twice a year, possibly as part of your semiannual service visits.

Refrigerator

Many refrigerators have water filters that service icemakers and in-door water dispensers. According to Holmes, most manufacturers recommend replacing them every six months. Says Holmes, “If you keep a water jug with a filter in the refrigerator, you tend to pay more attention to that but forget about the other filters in there.” If you aren’t ­interested in filtering water, many units come with a bypass plug.

Vacuum cleaner

Disposable vacuum cleaner bags also act as filters. Never let them fill to the maximum capacity, Kirby says. Replace the bags when two-thirds full. Holmes cautions that a stuffed bag can burn out a motor. “If your bag is clogged, you might detect a slight burning smell,” he says. “This means something is overheating.” If you have the option of adding a HEPA (high-efficiency particulate air) filter, it can trap even smaller particles, which is especially beneficial if you have allergies. These are often good for one year. Confession: I just checked my HEPA filter: It was last replaced in 2014. Major filter fail.

Chat Thursday at 11 a.m. Matt Blashaw, who hosts the HGTV series “Yard Crashers” and “Vacation House for Free,” joins staff writer Jura Koncius for our weekly online Q&A on decorating and household advice. Submit questions at washingtonpost.com/home.

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