Why Is My AC Taking So Long To Cool My House?

Woman laying on the floor with her arm over her forehead next to a floor fan blowing air

When you come home on a sweltering day, you probably head straight to your air conditioner to get the relief you need from the heat. After some time, though, you barely notice a difference in your home's temperature. Confused, you check and see that your AC unit is running just fine. So, why does your house still feel warm?

A number of causes can result in your air conditioner taking longer to cool your home. In this guide, we'll explore these possible issues:

  • Dirty air filters
  • Incorrect AC size
  • Refrigerant leaks
  • Thermostat issues
  • Dirty coils
  • Ductwork problems
  • Lack of maintenance

Need a reputable HVAC contractor to get your AC up and running again?

Whether you need to schedule an AC repair or improve your AC maintenance plan, we're here to help. Since 1979, our NATE-certified technicians have provided top-tier, good old-fashioned service and honest, upfront pricing. Regular maintenance goes a long way in preventing common issues, so schedule a service with us today.

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Dirty Air Filters

Throughout your AC unit's life, its filter accumulates various substances. Dirt, dust mites, pet dander, debris, and other buildup can get trapped in your AC filter. Once this buildup reaches a certain point, it reduces your air conditioner's efficiency. This makes the unit work harder to cool down your home, which is why it takes longer to reach the desired temperature.

Incorrect AC Size

The size of your air conditioner matters when installing a new unit in your home. To calculate the cooling capacity of your AC unit, aim for 20 BTUs per square foot of space. By following this rule of thumb, you can help boost the energy efficiency of your AC system. Calculating the right size will ensure your home reaches the desired temperature quickly.

Refrigerant Leaks

Refrigerant fluid travels through your AC system while absorbing and releasing heat. Without refrigerant, your air conditioner cannot cool your home. If your AC takes a while to get cold, it may be leaking refrigerant. A leak prevents your AC unit from absorbing and releasing the necessary heat for optimal functioning, resulting in a much longer cooling process.

Thermostat Issues

If you still can't figure out why your AC unit is struggling to cool, you might have your thermostat to blame. Not all air conditioning units adjust the temperature based on the level of heat outside. If your AC system isn't automatically reaching your preferred temperature, make sure your thermostat is programmed to the right setting.

Dirty Coils

Once the refrigerant in your AC unit has absorbed any excess heat, it travels through the evaporator coil before it gets released into the outdoor air. If the evaporator coil is dirty, your air conditioner will struggle to absorb the necessary amount of heat. This forces your AC system to take longer to cool your house.

Ductwork Problems

Your home's ductwork functions on a continuous cycle to push warm air out of your home and bring cool air back inside. If your ducts have hidden leaks, this process will take much longer than usual. Common signs that your ductwork needs repair include uneven temperatures throughout your home and excessive dust from the supply registers.

Lack of Maintenance

Many common HVAC issues can be prevented with regular maintenance. During a tune-up, our HVAC technicians will diligently clean out your air filters and inspect your AC unit's components to identify any issues. Regular cleanings reduce the time it takes for your AC system to cool down your home.


Boost the efficiency of your air conditioner with our professional services.

Routine maintenance significantly affects the performance and lifespan of your AC system. Our knowledgeable technicians offer 2-hour appointment windows and fast, convenient scheduling to make their services as accessible as possible.

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