A dirty filter can cause allergens to build up in the duct system and remain there for months, leading to poor air quality in your home. Fans drive air through the filter, and if it becomes too clogged with dust, dander, and debris, then the blower has to work harder to get air through a clogged filter. This can result in hot and cold spots in your home, making it difficult to achieve desired indoor temperature levels. The same is true for your car's engine air filter.
Over time, the engine air filter can become dirty and lose its ability to filter air entering the engine. This can lead to engine misfires, rough idling, and hard starts. A decrease in fuel consumption is often a sign that something is wrong. The air filter contributes to fuel efficiency, but a dirty filter can reduce oxygen flow, causing the vehicle to burn more fuel to compensate.
When air filters become clogged and dirty, they begin to allow dust and dirt to pass through the ventilation system to your home. This creates more dust, leaves a film on all surfaces, and recirculates that same dust and dirt through the system over and over again. One of the worst things about a dirty oven filter is that all the dust and debris that needs to be filtered out is recirculated back to your home. So why does an air filter matter? Pleated filters made of disposable nonwoven fabric have smaller pores and the pleats increase the surface area of the filter so that it can contain more particles than a flat surface.
If you don't routinely change your heating and cooling filter, it can become clogged with dust, dander, and debris. This will allow all the dust and debris that needs to be filtered out to circulate back to your home. Manufacturers vary in their recommendations for how often the air filter should be changed, but if you notice any of these signs that the air filter is dirty - such as a darker color with visible dirt and debris - it's time for them to inspect it. Just like replacing your car's engine oil and air filter every 3,000 miles, a clean HVAC air filter protects your heating system from being damaged and ultimately completely failing.