That balky appliance may just need a new filter

Dryers that don’t dry, vacuum cleaners that don’t clean, and air conditioners that don’t cool may all be plagued by the same problem: a clogged or dirty filter. To keep many top-performing appliances in tip-top shape, you have to clean or replace the filter. When Consumer Reports tests vacuums, air conditioners, dishwashers, and other appliances, filter replacement is one of the things we consider as part of our ease-of-use score. Here are some recommendations from our experts.

Dishwashers
Dishwashers are equipped with either an automatic filter that grinds food particles so they wash away with the waste water or a manual filter that you need to clean yourself. The grinders can be noisy so quiet dishwashers often have manual filters. They should be cleaned at least every three to six months depending on how often you use your dishwasher. And some manufacturers recommend cleaning the filter every two or three weeks so check the owner’s manual. “Dirty filters won’t damage a dishwasher but will affect its performance,” says Larry Ciufo, who tests dishwashers for Consumer Reports.
Tested models. The Bosch Ascenta SHX3AR7[5]UC, $700, which is a CR Best Buy, has a manual filter and is one of the quietest models during fill, wash, and drain. In our dishwasher tests, it was especially energy efficient, using almost six gallons of water in a normal 93-minute cycle. Among models with self-cleaning filters, our experts recommend the Frigidaire Gallery FGHD2472PF, $700, which scored excellent in washing and features a soil sensor and a stainless-steel tub.

Microwave ovens
Yes, there are filters in microwaves. Over-the-range microwaves have a filter underneath to ensure that the vent has proper airflow and ventilation. A clogged filter doesn’t exhaust properly or adequately capture cooking fumes or grease particles, leaving a sticky film on appliances and kitchen walls. To keep it clean, wash the filter in warm, soapy water at least twice a year and more often if you cook at home every night. Some microwaves have dishwasher safe filters. “If your filter has grease buildup, it can start dripping on your cooktop,” says Ciufo, who also tests microwaves.
Tested models. Only two of the 75 over-the-range microwaves in our microwave tests received an excellent score in venting—the Kenmore Elite 8852[2], $550, and Panasonic Genius Prestige NN-SD297[SR], $430. They were also top-notch at performing their primary functions of cooking, reheating, and defrosting food.

Clothes dryers
A dirty lint filter extends drying time, using more energy and costing you money. In addition to cleaning the lint filter between every load of laundry, you should inspect the dryer duct and cabinet regularly to check for any lint buildup, which poses a fire hazard. This should be done per the owner’s manual. Some newer dryers have blocked-vent sensors that detect reduced air flow but not all performed well in our clothes dryer tests, making a visual inspection the safest bet.
Tested models. In our dryer tests, the electric Samsung DV50F9A8EVP, $1,100, was excellent overall and its Vent Sensor successfully detected a blocked duct. Another recommended model, the LG DLEX3470[W], $1,000, features a blocked-duct indicator that reliably detected a fully blocked vent. Neither was good at detecting a partially blocked vent.

Air conditioners
All window air conditioners have a filter and many come with a filter indicator that signals when it needs cleaning. If yours doesn’t, check the filter at least once a month during periods of heavy use. If the filter is dirty, it affects the unit’s ability to cool your space. To clean the filter, remove it and and wipe it with a damp paper towel. You may also be able to use the vacuum’s upholstery attachment. As our testers found, some filters are easier to remove than others so check that function when you’re in the store.
Tested model. The LG LW8010ER, $220, is a CR Best Buy among midsized air conditioners and scored well on our ease-of-use test, which includes changing the filter. It was also quieter than most units in our air conditioner tests and provided excellent comfort.

Vacuum cleaners
Failing to change the filters in your vacuum cleaner may cause it to lose suction or spew dust. Changing the filters regularly, especially on bagless models, saves work and aggravation. Frank Rizzi, who tests vacuums for Consumer Reports, says that every model is different so you should consult the owner’s manual to see how often the filters should be changed and whether they’re washable. If you no longer have the manual, you can usually find a copy online.
Tested models. In our vacuum cleaner tests, the upright, bagged Kenmore Progressive 31069 was excellent at cleaning bare floors and pet hair and very good at carpet. It has low emissions and excellent air flow. At $200 it’s a CR Best Buy. The bagless Hoover WindTunnel T-Series Rewind Bagless UH70120, $130, another CR Best Buy, had similar scores and made our list of recommended vacuums.

Water filters
Water filters have different lifespans depending on the type. Typically, the filter in a carafe water filter is good for 40 gallons while a filter in an undersink model can handle between 100 and 500 gallons of water. It’s up to you to keep track, as not all water filters indicate when it’s time to change the filter. Failing to periodically change it can result in water that’s dirtier than before filtration.
Tested models. A CR Best Buy, the Clear2O CWS100A, $23, has a filter-life indicator that tells you when it's time to change the filter. In our water filter tests, it was superb at removing lead and organic compounds in our tests. The Pur FM-3700B, $30, is a recommended faucet-mounted filter that also has a filter-life indicator. This model had impressive lead filtering and superb removal of organic compounds with minimal clogging.

Coffeemakers
Some coffeemakers, including many Cuisinart models, come with charcoal water filters to filter out the off-taste of water that’s highly chlorinated. They should be changed every six months. The price of a single charcoal filter can be from $5 to $20, depending on the brand. “If you don’t want to spend money on these filters, you can use water that’s already filtered and run an occasional cleaning cycle,” says Ginny Lui, who tests coffeemakers for Consumer Reports. To clean the machine, use a mixture of water and white vinegar but consult your owner’s manual for the procedure and the proper proportions.
Tested model. The Cuisinart Crystal SCC-1000 Limited Edition Perfec Temp, $200, drip coffeemaker is gussied up with Swarovski crystals, but it was also a gem in our coffeemaker tests. First, it's the only model that can brew a full 14 cups—a "cup" being about five ounces in industry parlance. And while it's expensive, it had top-notch brew performance and was easy to use.

—Izabela Rutkowski