Home filters you should never ignore

You can't see most of the filters in your home, but they're there, keeping toxins and other bad stuff from the air that you breathe and the water that you drink. Besides their obvious health benefits, filters keep your home's systems and appliances shipshape. That is, unless they become seriously clogged or damaged, in which case they can do more harm than good — dumping contaminants back into your drinking water, for example.

So, which filters are the most critical to maintain? Here are the five essentials, according to the pros at HomeAdvisor:

Central heating and cooling systems

If your home uses forced-air heating and/or cooling, the systems' filters needs to be changed at least once a year. The filter is usually located in the blower compartment or it could be built into the nearby ductwork. New filters are available at the home center, or you can order them online. Be sure to turn the system off before making the switch. And note that air only flows in one direction through a filter, so it's important to insert it the right way. Check the filter frame for arrows indicating which side should face the furnace.

Pro tip: Window AC units also have filters that need to be cleaned. Use the upholstery brush on your vacuum to suck away dirt and dust, then wash with soap and water.

Clothes dryers

You're probably good about cleaning your dryer's lint screen. But it's also critical to check for lint build-up in and around the dryer duct and vent filter. Of the 2,900 home dryer fires that are reported each year, failure to clean the unit is the leading cause, according to the U.S. Fire Administration. For best results, invest in a dryer vent cleaning kit, which makes it easy to access the vent filter through the dryer's ductwork.

Pro tip: If your clothes are suddenly taking longer to dry than normal, there's a good chance you have a clogged filter.

Drinking water

Water filters remove harmful contaminants like lead and chlorine, as well as impurities that can give tap water an off taste. But if you leave the filter too long it will clog up, potentially resulting in water with higher levels of contamination. Carafe-style filters usually need to be changed monthly, while large countertop or under-sink systems might only require an annual changing.

Pro tip: Don't forget to change the filter on your refrigerator. That will lead to safe, better-tasting water and ice cubes, and it will also help prevent ice maker failures.

Vacuum cleaners

If your vacuum's filter gets dirty enough it will eventually start to lose suction, but even before it reaches that point it might start to spew dust and other tiny particulates back into the air. That can seriously affect the indoor quality in your home, especially for allergy sufferers.

Pro tip: When shopping for a new vacuum, look for a model with a washable filter. It will save you a lot of time and money over the long haul.

Air purifiers and dehumidifiers

These devices have filters that can be cleaned quickly and easily to maintain performance and minimize the risk of equipment failure. Many air purifiers have a second HEPA filters that needs to be replaced every 6-12 months, depending on frequency of use and the quality of your home's air. Since dehumidifiers often sit in dank areas, always check the filter for signs of mold, mildew and dust mites. If any are present, it's time for a new filter.

Pro tip: Air purifiers and dehumidifiers both can improve air quality, but there are usually underlying issues that need to be addressed. For example, poor indoor air quality might be caused by insufficient exhaust fans in the home. Dank basements, meanwhile, are often the result of water reaching the foundation walls. While a dehumidifier can keep the basement dry, dealing with the foundation problem will be a more permanent solution.