AC Not Cooling Below 75 – Reasons And Solutions

Published: Updated:
AC Not Cooling Below 75

An air conditioner is one of the home essentials that enhances comfort. However, it sometimes develops problems. After calibrating your AC unit below 75 degrees, it might fail to cool below this point. 

But why?

Key Takeaways

  • The primary reason for an AC not cooling below 75 degrees is a dirty air filter.
  • The air filter traps unwanted elements like dust, dirt, and debris, ensuring they don’t reach the evaporator coil. In doing so, they may block the filter, causing your AC unit to malfunction.
  • If the air temperature is under 92 degrees and the AC can’t cool down the temperature, be sure to check the filter.

Read through to learn the most common reasons for your AC not cooling below 75 degrees. You’ll also learn the possible fixes to these problems. 

Why Is My AC Not Getting Below 75?

Your AC is not getting below 75 degrees for the following reasons. 

  • A clogged air filter
  • An obstructed condenser
  • Refrigerant dripping
  • An AC that’s too small
  • Leaky pipes
  • An older air conditioner

Let’s discuss these in detail.

A dirty/Clogged Air Filter

The primary role of the air filter is to trap unwanted substances that travel along with air into the evaporator coil. With time, dust particles and debris may clog the filter. This feature will limit your AC cooling efficiency if left unaddressed. 

If a dirty air filter is a reason for your AC not cooling below 75 degrees, we recommend you replace it with immediate effect. 

Related: Portable AC vs. Window AC: Which one to Choose?

A Suffocating Condenser

A Suffocating Condenser

The AC condenser collects your room’s heat and dissipates it into the air outside the room. However, the condenser needs enough breathing space to work efficiently. If you suffocate the condenser, the hot air will go back into your room’s air, making it impossible to attain lower temperatures. 

To solve this issue, you should remove debris, shrubbery, and any foreign material lodged in the condenser.

Related: 5 Best Mini Split Heat Pumps for Cold Weather

A Refrigerant Leak

The refrigerant is the chemical responsible for cooling air in your room. So, if the chemical leaks and the AC unit runs low on it, the AC won’t cool the air in the home efficiently. 

You can address this issue through a regular inspection program. If you notice any refrigerant leak, get a technician to repair and recharge the refrigerant leak. 

Below are the signs for a refrigerant leak.  

  • Your AC refrigerant lines have ice deposits
  • The evaporator coil is frozen
  • The refrigerant lines produce hissing sounds
  • Your energy bills suddenly increase

An Undersized AC

An undersized AC unit will struggle to attain your desired room temperature. AC units come in different sizes; the larger the unit, the more cooling power it has. 

Ask a professional technician to conduct a manual J calculation if you have an undersized AC unit. They will advise you if the unit is enough or too small for your home. Be sure to upgrade the unit to a larger one if it is small. 

Related: Ultimate Review Of Best Portable Air Conditioners In 2023

Leaky Ductwork

The air ducts supply cool air throughout your home. If it develops escape holes and pores, cool air may leak and fail to cool down desired spaces. 

If you believe your AC has leaking ductwork, call a technician to inspect and seal any leaks.

Related: Swamp Cooler vs. Air Conditioner – A Detailed Comparison


An Older AC 

When your AC ages, its efficiency drops, and it might fail to cool your room to the desired temperature. 

If you have used your AC for over ten years, consider replacing it with a new one. Consult a professional to determine if it is worth upgrading your AC unit. 

Why My AC Temperature Is Not Going Down

Your AC temperature is not going down because of the reasons below. 

  • Weak or Dead Thermostat Batteries
  • Clogged Drain Line
  • Tripped Circuit Breaker
  • Refrigerant Leak


Weak or Dead Thermostat Batteries

Despite its small size, the thermostat is an essential part of the HVAC system. If you have a battery-powered thermostat and the battery is weak, the thermostat won’t run. 

If this is the case, we recommend you replace the batteries with new ones. If replacing the batteries doesn’t solve the problem, test your thermostat with a thermometer.


Clogged Drain Line

If your drain line clogs, the AC won’t go down. If your compressor has puddles, the drain line might be clogged. 

When the drain line clogs, water in the drain pan will rise. When it reaches a certain level, the float will deactivate the compressor, which shuts down the thermostat. This feature will cause the AC not to cool down the air temperature. 

If this is the case, you need to unclog the drain pipe. To do so, follow the steps below.

  1. Turn off the thermostat power. Do the same with the breaker.
  2. Locate the AC drain line. You’ll find this near the condenser unit. Have a bucket with you if the brain line is full.
  3. Remove the cap on the T-shaped vent to access the drain line. 
  4. Inspect the drain line for blockages. Remove them manually if visible, but ensure you wear protective gloves.
  5. Flush a vinegar solution into the drain line if the blockage is beyond your reach. Pour a quarter cup of vinegar from the side where you’ve removed the cap. Stop when it is full. 
  6. Leave it for about 30 minutes before flushing the pipe with water. If you notice an unsteady water flow, repeat the process or have a professional help you unclog it. 


Tripped Circuit Breaker

If your hard-wired thermostat has tripped circuit breakers, the AC may fail to go down. 

To address this issue, find your electrical panel and locate a breaker that can cover the area of your thermostat.

If your labeled breaker is fine, conduct a manual check to ascertain if it is engaged. Engage it if not. However, if your breakers are not labeled, you’ll need to check each breaker to determine if they are fully engaged.


Refrigerant Leak

The refrigerant is the chemical responsible for cooling air in your room. So, if the chemical leaks and the AC unit runs low on it, the AC won’t cool the air in the home efficiently. 

Check if your refrigerator has any of the following signs.

  • If the refrigerant lines produce hissing sounds
  • AC refrigerant lines have ice deposits.
  • If your evaporator coil is frozen
  • If your energy bills suddenly increase

If you notice any of these signs, consult a licensed technician about repairing and recharging the refrigerant leak. Note that refrigerant may be toxic, and you’ll need a professional to handle it.

Related: Fans That Cool Like Air Conditioners – What Are Your Options?


AC Not Cooling Enough

If your AC is not cooling enough, the following might be the problem.

  • Irregular maintenance
  • Improper AC unit placement
  • Clogged air filters/condenser coils


Irregular Maintenance 

An AC requires regular maintenance to keep them working optimally. A professional should always inspect the compressor for damage, refrigerant leaks, condenser coil issues, and many other features. 

The AC will not cool enough if you have an irregular maintenance program. 


Improper AC Unit Placement

An AC has indoor and outdoor units. You need to place them properly to ensure they work efficiently. For instance, an indoor unit meant for a medium room won’t be enough to cool a larger room. 

Also, placing indoor units near heat sources or open windows would be best. For the outdoor unit, ensure you place them away from direct sunlight to avoid the compressor overheating.


Clogged Air Filters/Condenser Coils

Debris and dust particles may clog the air filters and the condenser coils. If so, air won’t move freely, and the AC may not cool the room efficiently.

Why Is My Air Conditioner Running but Not Cooling the House

The condenser coil might be clogged if your air conditioner runs but does not cool the house. Debris and dirt particles that move with air may build up in the fin to clog the coil, thus, a low cooling capacity. 

Other reasons your running AC doesn’t cool the house are as follows. 

  • Incorrect thermostat configuration.
  • Blocked air filters
  • Frozen evaporator coil
  • Undersized air conditioner
  • Refrigerant leak

Related: Ultimate Review of the Best Smart Air Conditioner in 2023



There are many reasons why your AC may not be cooling below 75 degrees. From a dirty air filter to a malfunctioning thermostat, there are a variety of issues that could be causing the problem. However, troubleshooting and implementing the solutions outlined in this article can get your AC back to working correctly in no time. Remember to regularly maintain and service your unit to prevent future cooling issues. If the problem persists, it is recommended to seek professional help to avoid further damage or costly repairs.

Sharing is caring!

You may also like