Why Does the AC Take So Long to Cool Down the House?

When it’s scorching outside, you count on your cooling to keep things comfortable inside. But is your AC taking a long time to cool down the house? This is common on sweltering days, which strain your cooling harder than average. However, if it’s not very hot outside and your AC is still struggling, your air conditioner may have a problem. Follow these tips to help you troubleshoot the problem. 

Dirty Air Filter 

A clogged filter is the most frequent reason an AC system takes too long to cool down the house. The purpose of a filter is to catch airborne pollutants that can damage delicate HVAC equipment. More efficient filters even catch tiny airborne contaminants to enhance indoor air quality

As time passes, the filter becomes blocked up with dust, pet hair, and textile fibers, limiting the flow of air. Besides making the AC unit take longer to cool down the house, this situation can also result in larger energy bills, higher wear and tear, and overheating. 

Solution: Check your air filter each month and exchange it if it appears dirty. Don’t wait past three months to replace the filter or follow the manufacturer’s recommendations. If you’re unsure where an air filter is located, talk to your HVAC technician at your next service appointment. 

Improper Thermostat Settings 

Your thermostat has to be compatible with your AC system to function effectively. Then, you have to set it correctly to maintain a comfortable temperature. Using a programmable or Wi-Fi thermostat offers the best results. 

Solution: If you want to update your thermostat, require help learning about programmable options, or may not feel comfortable programming a thermostat on your own, get in touch with an HVAC technician at Stevenson Service Experts for support. 

Dirty Evaporator Coil 

Split-system air conditioners come with an indoor unit and an outdoor unit. The indoor unit houses the evaporator coil, which takes in heat from the air via the refrigerant. It’s more difficult for the refrigerant to soak up heat effectively if the evaporator coil is dirty, making it take more time to cool your house. 

Solution: Get in touch with our HVAC professionals to clean and tune up your air conditioner. An element of this maintenance includes cleaning out dust and grime from the evaporator coil to enhance cooling efficiency. 

Dirty or Obstructed Outdoor Unit 

Your AC system’s cooling cycle requires moving heated refrigerant to the outdoor unit, where it ventilates heat away from your home. Unfortunately, if the outdoor unit is dirty or overgrown with encroaching plants, the cooling cycle can be less effective. 

Solution: Carefully hose off the outdoor unit to get rid of dust, cobwebs, pine needles and grass clippings. Then, trim back bushes to at least 12 inches from the unit to improve ventilation. 

Refrigerant Leak 

Refrigerant is vital to effective cooling. Typically, this substance moves in a closed loop back and forth between the indoor and outdoor units. If a leak develops and your air conditioner loses refrigerant, it becomes more difficult to handle the cycle of absorbing and releasing heat from your home. 

Solution: Only a licensed technician can fix refrigerant leaks and replenish the system. If you think you’re dealing with this problem, call our HVAC specialists for help right away. 

Leaky Ductwork 

Air ducts are the arteries and veins of your HVAC system. A leak in either the return or supply side might make your air conditioner work harder and longer to cool your home. 

Solution: If you notice uneven temperatures and excessive dust throughout the house, call Stevenson Service Experts to take a look at your ventilation. Duct sealing or replacement can fix the problem. 

Dirty or Blocked Air Vents 

Conditioned air can only flow around your home when the supply and return vents are open and unobstructed. Closing too many vents can even throw off the system’s balance, contributing to increased breakdowns and repair costs. 

Solution: Take a look at the vents in each room, ensuring they’re open and not blocked by furniture, carpeting or window treatments. 

Outdated or Undersized Air Conditioner 

Did you put in your air conditioner more than 10 to 15 years ago? As it ages, the unit becomes less efficient and may be unable to maintain a comfortable home. Likewise, have you recently completed a home addition or made other modifications? This may result in an undersized air conditioner that can’t keep up with demand. 

Solution: The only fix for an outdated or undersized air conditioner is to exchange it. Trust our licensed HVAC technicians to size and install your new unit for comfort and efficiency. 

Schedule AC Repair with Stevenson Service Experts 

If your troubleshooting efforts prove ineffective, it’s time to contact the HVAC professionals at Stevenson Service Experts. We provide fast, efficient service to get your AC back up and running right away. You can rest easy knowing our technicians follow the highest standards of support to ensure your long-term comfort. Contact us to request air conditioning repair or any other HVAC services today. 

Savings For You

See All Offers Here >


  • Save $50 on a Paid Service
  • Written 100% Satisfaction Guarantee
  • Plus, ask how to save an additional 15% and waive your trip charge!


  • Upgrade to Worry-Free Comfort with the Advantage Program and make NO payments for 30 days!

© 2024 Service Experts, Service Experts Heating & Air Conditioning, and the Service Experts logo and design are registered trademarks of Service Experts LLC and used under license by SE Canada Inc. All Rights Reserved. *Not applicable to the Advantage Program. See your signed Advantage Program Agreement for full details and exclusions. 100% Satisfaction Guarantee is subject to certain restrictions and limitations as set forth in the applicable Terms and Conditions.