How Often Should Furnace Filters be Changed?

The time span of each furnace filter varies from different households, and thereby, making a comparison among the different household HVAC systems, and furnaces should not be made. Replacing the furnace filters entirely depends on the household condition. Some factors may have triggered its clogging. Usually, dust is the common culprit in clogging the furnace filters. There are houses prone to be infiltrated by dust, and despite the constant cleaning, dust always finds its way to attach to home appliances, furniture, bedsheets, and even curtains. If you have a home condition that is oftentimes having dust, it is a must to check the filter of your furnace if it is already gray and dust almost covered it, and the furnace runs faster than usual. Then that is already a green light for you to change your filter. 

Keeping some furry buddies at home may also increase the chance of having clogged filters. The fur of our pet contributes to the pet dander in the air and may eventually clog your filter.

The timespan of your filter may also be greatly affected when you have a house remodeling. It is a known fact that remodeling makes a lot of dust and debris. The airborne dust and debris may come from the sanding, scraping, and even in floor installation.

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There could be other zillion factors that can be identified that cause the clogging of your furnace filter and the need to have it replaced. Replacing the filter will ensure that the dust-related particles will be kept at bay from circulating inside the house.

clogged furnace filters

Replacing the furnace may seem to be an easy task. All you have to do is to loosen the screws in its filter cover if it is located behind the return air vent. If it’s the side furnace‘s filter, you can just simply pull it out from the slot. Since the filter is clogged with dust, tiny particles of hair, and other air particles, you can expect that it is already dirty and that you must properly dispose of it, together with your other trash. After removing the clogged filter, just simply put the replacement filter on the slot. After doing so, make sure to set a date to indicate the date of the filter replacement.

You must be aware of the date of replacement in order for you to determine the date on which it is needed to be replaced. Usually, in normal conditions, filter replacement must be done within every ninety days. But still, it is entirely dependent on your home condition and the type of weather condition that your place has.

If your house is located in a place that has warm weather, most likely than not, you are using an air conditioner. Still, you need to constantly check your HVAC system for some dust and dirt that may have been sucked by the air conditioner system. Make sure that you have a clean filter to ensure that you will enjoy the coolness of clean air.

Living in Southwest that has temperate weather may connote that you could have used the furnace a couple of times and thereby may follow the 90-day standard replacement period, but the scenario is not the same if you are a Northern dweller that it is a must for you to use your furnace every day and it could have drawn more air into its filter then do not follow the standard 90-day rather change your filter within the 30 or 60-day period.


You must also consider checking the Minimum Efficiency Reporting Value (MERV) of the filter. You must remember that a dense filter means it must be frequently changed. For residential furnaces, the ideal MERV is about 6-12, and below such MERV may mean that the filter may not efficiently block the airborne dust and particles. MERV of 12 and above are intended for industrial, commercial, and hospital use.

The efficiency of the filter in blocking airborne dust, particles, viruses, and bacteria is being determined by the level of MERV. A higher MERV means more efficient it is in blocking the airborne particles. The reason behind it is that the higher MERV means that it has smaller holes that prevent the particulates from getting through. But since it has smaller holes, it also has the tendency to be immediately clogged and thereby the need for frequent replacement of the filter.

Clogged filters negatively impact home air quality and also drives the furnace into working harder to shorten the useful life of the furnace. The owner’s manufacturer’s manual specifies the most reliable furnace MERV rating. It should be generally 6 to 9 MERV rating before changing the furnace for 90 days, while every 60 days if the rating is 10 to 12.

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