The 90-day recommendation is for 1 and 2 inch filters. If you have a thicker model, the filter life is extended. For 3- and 4-inch filters, plan a replacement approximately every six to nine months. If you have larger 5- or 6-inch filters, you'll need to change them every nine to 12 months.
It's important to note that this is just a general recommendation. There are some factors that can shorten or extend the time between furnace filter replacement intervals. In most cases, you should replace the filter at least every three months, even in summer. If you can't seem to remember to do it, a good rule of thumb is to change your furnace filter every time the seasons change.
The frequency with which you need to change your furnace filter comes down to what happens in your home. Here's what you need to know. However, northerners whose furnaces have no rest for months may want to change their filter every 30 to 60 days, because more air is being drawn through the filter and it will clog more quickly. Rather than just stepping out of the standard timeline, below are some special signs and considerations that will let you know when to change a furnace filter. The longer the filter is in place, the more dirt, dust and allergens are trapped, clogging the filter and decreasing its efficiency.
If your household members suffer from allergies or asthma, furnace filters should be changed more frequently. However, they may not know that they also need to change the furnace filter at regular intervals. No two houses are the same, so despite guidelines, you may need to change your furnace filter more often than your neighbor. Changing your furnace filter regularly ensures that the air in your home remains free of dust and other contaminants. If outdoor temperatures are extremely cold or hot and your furnace or air conditioner is running non-stop to keep up to date, filters that should have lasted 90 days will need to be changed every 30 days to ensure your HVAC system is working properly.
In summer and winter, owners often change furnace filters more frequently than in autumn and spring. If you have multiple smokers in your home, you'll need to adjust those numbers to once a month for one- to two-inch filters, two months for four-inch filters, and three months for five-inch filters. Considering the factors that influence the air quality inside your home is a good measure of how often furnace filters need to be replaced. Filters play a vital role in the overall operation of your furnace and can have a notable impact on the air quality of your home. Without a filter, the furnace would stop working quite quickly because the equipment would be too dirty to work properly.
Depending on your lifestyle and the type of furnace filter you choose, you may want to change it more often. Dirty furnace filters are a disaster for heating and cooling equipment, home comfort, and indoor air quality. If you continue to use the furnace when the filter is dirty, it can cause dust, hair, mold and other debris to accumulate inside the heating and cooling system.