Central air conditioning is pretty much the standard for homes in our area. If you are trying to fight the heat and humidity of the Florida summer with window units, you really need to rethink your strategy. Whether you’re using a central AC to cool your home, a furnace to warm it on our occasionally chilly nights, or a heat pump to do both, you really need to keep your air filter in mind. Forced air heating and cooling is going to suffer greatly, in a number of ways, with a dirty filter in place.
Yes, you should be scheduling annual maintenance for your HVAC systems (bi-annual for heat pumps), and yes, your maintenance technician should be cleaning or replacing your air filter as needed. Once or even twice a year is simply not enough, though. These standard air filters typically need changing every 1-3 months. Failure to keep up with this vital maintenance task is going to result in some serious issues for your comfort, your budget, and your system itself.
Problems Caused By Dirty Air Filters
If you think that poor indoor air quality throughout your house is the main concern here, and the fact that your allergies are not acting up means that a dirty filter is really no big deal, you are focusing on the wrong points. Yes, it is possible that a very dirty air filter will have a negative impact on the indoor air quality in your home. The air may bypass a dirty filter as it seeks the path of least resistance, squeezing through it and its frame and introducing pollutants into the air ducts. However, the primary function of this filter is really not to protect indoor air quality throughout your home. Instead, it mainly serves to protect your system itself.
The air filter prevents pollutants like dust and dirt from building up on the vital components within that system. If the filter is very dirty and air does enter the system, then its performance will be affected. Everything from coils in heat pumps to combustion chambers and heating elements, along with controls and safety devices like thermocouples, really do need to be kept clean in order to function properly.
Aside from the issues with dirty components in the system itself, that dirty air filter is also going to create a lot of airflow resistance in the system. When that happens, the system is simply going to have to work harder than it should have to in order to force air through the filter and, thus, throughout your home. This will negatively affect the energy efficiency with which your system operates, leaving you to pay more for what is likely to be a lesser performance from your forced air HVAC system.
Operational problems like short cycling can also develop. Short cycling occurs when the increased strain on the system caused by increased airflow resistance causes the system to cycle down prematurely, leading to very frequent starting and stopping. That drags efficiency down even further, and the wear and tear greatly increases the risk of HVAC repair needs. This isn’t the only cause of short cycling, but it is a common one and the easiest to resolve.