For Merv 8, 11 and 13 filters, it is recommended to change the filter at least every 3 months for optimal filtration and healthier air in your home. However, if the air filter is made of fiberglass, experts suggest changing it every 30 days. Pleated filters can last up to six months if replaced regularly. Most air filter manufacturers and HVAC companies suggest changing the air filter every 90 days or 3 months.
This may vary depending on the location of your home, if you have pets, and the age of your system and equipment. If you have pets at home, it is best to change the filter every 60 days or 2 months. For households with several pets or people with allergies or respiratory conditions, it is recommended to change the filter every 20 to 45 days. Vacation homes or empty houses that aren't used much can wait to change filters every 9 to 12 months.
The more you use your home, the more often you'll need to change your air filter. It should be changed at least every 90 days. During peak summer and winter months, filters that normally last 90 days should be changed every 30 days. Filters such as the Honeywell Ultra Efficiency filter can last up to 90 days if replaced regularly.
A clean filter is necessary to prevent dust from passing through the HVAC system and accumulating in the internal coils of the air conditioner, reducing its efficiency. According to the American Allergy and Asthma Foundation (AAFA), “indoor air quality is as important as outdoor air quality”. A dirty air filter restricts air flow, leading to poor air quality, higher energy bills and eventually causing the system to fail. A good oven filter can help improve air quality in your home, but a dirty air filter will do the opposite.
To test if it's time to change the house's air filter, hang a white sheet several inches from the ventilation grille and check if it turns gray. As air moves through a building's air conditioning system, air filters trap and accumulate large and small particles such as dust, allergens and microorganisms. To keep air quality under control and your home clean, you'll want to replace the filter at least 2 to 3 months apart. If you have poor air quality outside and inside your home, you'll need to replace your air filter more often.
The average MERV efficiency range of 5 to 10 requires filter changes in about two to three months. If your furniture gets dirty soon after cleaning the house, it could be a sign that the oven filter is clogged and no longer effectively removes dust from the air.