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Filter Talk: What You Need to Clean or Change Before Winter

There are two things most home appliances need. The first is the power to run them. The second is a filter, to carry out what they need to do efficiently. Almost everything from your air conditioner and dryer to your vacuum cleaner uses a filter to prevent clogging and ensure pain-free operation.

Incidentally, most of these appliances see heavy use during the fall and winter. So here’s a checklist of all the household appliances you will mostly likely use for the cold season.

1. Gas Furnaces

Top of the list of course is your furnace. This stout unit typically gets the most workout in winter, and you wouldn’t want to be stuck with a wheezing or dead cold furnace in freezing temperatures.

When taking out the old filter, be sure to note the arrow, which indicates the direction of the filter placement. Furnace filters are directional and should never be slotted in backwards lest it hinder the airflow.


Twice a year for cold areas that see more heating use

Annually for more temperate regions

2. Central HVAC and Heating

The performance of your combined force heating and cooling system is largely determined by the airflow, which in turn is regulated by the air filters. Washable filters are recommended to be cleaned every month, but disposable filters need to be changed according to the manual, ideally before the cold season. As a rule of thumb, the thicker the filter, the less often it needs to be changed.


Every 3-12 months, depending on the brand, model, and specific filter part

3. Air Cleaners

The third most used unit are air cleaners or air purifiers. With more people remaining indoors longer, air cleaners see more prolonged use during the cold season. They also tend to experience more clogging, especially if you use a wood-burning fireplace or stove.

Prefilters can usually be cleaned or simply wiped down every few weeks or once a month. However, homes with heavier usage or wood-burning heaters would do better with a weekly cleaning.

However, HEPA filters are disposable items and should not be cleaned, as well as filters that contain charcoal.


Every 6-12 months, or more often for homes with wood fireplaces

4. Humidifiers

Humidifiers are very useful during the cold months: they help keep the air more comfortable, reduce the chances of dry skin and respiratory problems, and help stop wood damage from lack of moisture in the air.

However, they also need more periodic maintenance, to prevent the formation of mold within the unit. Desktop humidifiers typically use a disposable filter, while bigger units use a combination of prefilters (which can be cleaned) and HEPA filters, which will need to be replaced.


Tabletop units – every 1-3 months depending on usage

Standing units – every 6-12 months depending on usage

Also check out our guide to cleaning and maintaining your humidifier.

5. Water Heaters

Another household item likely to see heavier use are water heaters, whether point-of-use, storage, or tankless heaters. Even municipalities with the cleaner water supply will tend to have a few contaminants, by virtue of the pipeline. Over time, these minute particles can build up into a sediment and impede the flow of water, causing your heater to work harder


For most units, it’s recommended to change the filter every 1000 gallons, or after about 4-6 months of use. Heaters with 40 gallons and below capacity may need more frequent cleaning or replacement.

For tips on cleaning your water heater, check out our maintenance guide for tankless and storage units.

6. Rangehoods

With barbecue season over, all cooking will be done indoors. Besides, stovetop cooking helps to moisturize the cold dry air and function as an alternative to humidifiers. However, frequent cooking can also clog your range hood.

The filter can be easily cleaned with hot water and degreasing soap, after letting it soak for 10 minutes. Stubborn grime or grease can be scrubbed off with a sturdy sponge. However, older filters may need to be replaced.


Every 6-12 months with normal use

Every 3-6 months with heavy use

7. Clothes Dryers

Lint clogs the primary enemy of clothes dryers. They extend drying time, lower performance, and shorten the unit’s operational lifespan. 

Make sure to check the following for obstructions:

  • Lint filters
  • Duct
  • Vent 
  • Sensors


It’s recommended to swap the lint filter every 6-12 months, or more frequently for bigger families

8. Dishwashers

Cold weather means less dining out, which results in more dish pileups. Dishwashers and grinders tend to see more frequent use in the cold season, unless you’re a fan of ordering pizzas and Chinese takeout.

Some units are equipped with automatic filters that are washed by the unit, but other models use manual filters that must be cleaned by hand every 3-4 weeks.


Every 3-6 months depending on the brand and size

Mickey Luongo

Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.

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