Essentially, most homes will have at least two air filters, because most homes have a return duct to go along with their air handler.
If you are utilizing return air grille filters, it is recommended that you avoid using furnace filters. Using both can restrict airflow too much, damaging your system.
Typically, a house will have 2 air filters in their intake vents. In some cases, there can be more or fewer depending on the square footage of the home or apartment and the number of floors that need to be supported by the central air system.
Check near the HVAC Unit
Some larger houses have more than one HVAC system, and each of these will have at least one filter. Take a look first for filters in or near the HVAC unit itself. These filters are most likely found next to the furnace or the air conditioning air handler.
You might wonder about the risks of running your AC without a filter, even temporarily. The simple answer is: not for long. Ideally, your AC should never operate without a filter for more than 6-8 hours. Going beyond this can negatively affect both your system's health and your home's air quality.
What happens if your HVAC filter is dirty? A dirty HVAC filter restricts airflow, which can lead to poor system efficiency, increased energy costs, and wear and tear on the unit.
Essentially, most homes will have at least two air filters, because most homes have a return duct to go along with their air handler.
If you don't change your air filter, it can quickly become clogged with dust and debris, preventing proper air filtration. This leads to a variety of issues for your HVAC system including system inefficiency, higher energy bills, inadequate air quality, and ultimately failure.
Filters are installed on the return side of the HVAC air handler to clean the air to protect the HVAC motor and to improve indoor air quality. Filters should also be installed in fresh air intakes to clean outside air that is brought into the home.
These are things every homeowner should know.
A dirty filter restricts the air flow into your HVAC systems air handler. This restricted air flow places additional strain on the air handler fan motor and could, over time, burn out the motor and cause your system to overheat and ultimately fail.
All central heating and cooling systems should have an air filter, but some HVAC units make filters harder to locate. The filter is commonly located in a return air grille, within the air handler, or external to the air handler in a filter rack.
Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.
Filters with a MERV rating of 1 to 7 typically cost between $5 and $20. Filters with ratings of 8 to 13 can cost anywhere from $20 to $150. HVAC systems in residential homes usually don't need (and often cannot handle) filters with a MERV rating of more than 13.
Central and outdoor air conditioning units rely on filters to circulate fresh, clean air throughout your home. Clogged filters can force your unit to work harder. You may find yourself leaving your unit on for longer stretches of time, too, and at maximum cooling.
First, check your filters and coils for dirt and debris that may be impeding airflow. Once you've cleaned the filters and coils, run the air conditioner with just the fan so that the ice accumulation can melt off. If the AC still doesn't blow cold air, it could be that refrigerant levels are too low.
Turn the unit off. Turning this off prevents the air from blowing dust and grit into your system. Open up your vent and remove the used filter.
Air filters that are overdue for a change are a common cause of HVAC system failure. Over time, dirt builds up in the heating and AC filters, causing components such as the motor to go into overdrive, which may eventually overheat your unit.
It may be difficult to locate on some HVAC systems, but you can usually find the air filter in the return air duct. Or, in layman's terms, that big metal grate on your wall, floor, ceiling, or utility closet door. Return air ducts can be just about anywhere.
The short answer: You can get away with running your AC without a filter for a short period of time. However, doing so for longer than 6-8 hours can hurt your system and decrease your home's indoor air quality.
A dirty air filter restricts airflow through the HVAC system making it harder to reach your desired indoor temperature at an increased cost.
Check the thermostat
You should check if it's been set to the correct temperature and also make sure it's set to “cool”. If the AC settings are not right, it won't turn on. You can also check if the batteries in the thermostat are fresh and replace them if needed.
While there are a number of commercially available coil cleaning solutions on the market, air conditioner coils can be cleaned with a solution of a mild household detergent and water. The detergent and water mix is applied to the coil using a low-pressure sprayer.