In short, yes. Not changing your furnace filter can significantly reduce the efficiency with which your furnace runs, causing damage to the furnace and possibly creating a life-threatening situation in your home. Neglecting to change the furnace filter can result in a house fire or in deadly combustion gases (carbon monoxide) combining with the air in your home.
For a furnace to operate properly, optimal air flow is necessary. If you do not change the filter, it will eventually become clogged with dirt, dust, and air particulates. The first consequence of not changing your furnace filter will be decreased efficiency. When this happens, you may notice dust or dirt around the air vents in your home or that you smell a dusty odor when the furnace is operating. Family members with dust allergies may have increased symptoms. The furnace will also run more often than it usually does, as it needs to work simply to maintain the desired temperature in your home. This will result in an increase in your utility bill.
Not changing the furnace filter decreases the amount of air that flows over the heat exchanger of your furnace and, consequently, the operating temperature of the heat exchanger rises. As the operating temperature exceeds the range for which it was designed, increased expansion of the heat exchanger results. A greater degree of contraction also occurs as the unit cools. Excessive expansion and contraction during the on/off cycle can cause warping and cracking. When this happens, the furnace either will become damaged to the point that it completely fails or – even worse – will operate under dangerous conditions that cause a house fire or leakage of poisonous gases into the home.
Changing a furnace filter is simple and can help you avoid costly repairs or replacement of the furnace, as well as keep your family healthy and safe. How often the furnace filter needs to be changed depends on various factors, including the type of filter used, the age and general condition of your furnace, and other factors including the presence of pets in the home, whether anyone in the home smokes, and environmental conditions. Consult your furnace manual for recommended guidelines for replacing the filter for your furnace. If you have further questions or cannot locate the manual, consult a licensed HVAC professional for assistance.