What To Do If Your Air Conditioner Is Running But Not Cooling Your House

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It’s no fun when the air conditioner doesn’t work, however, it happens. And it won’t be in the middle of winter as it happens. It will be the hottest day of the year, and no matter how low you set the thermostat, the air conditioner will not blow cool enough air. 


The condenser compressor (AC unit or heat pump) outside your house is just part of an air conditioning system. An indoor air handler unit (furnace or fan coil), an evaporator coil, air filter, thermostat, and copper tubing (refrigerant lines) that link the indoor and outdoor systems are all common components of split-system air conditioners. 


So, to the debate, “Why isn’t my air conditioner cooling the house?” There are a few options. But don’t be concerned. Only because your system isn’t cooling doesn’t mean you have to spend a lot of money on AC upgrades or a new system.


The majority of homeowners are capable of doing simple troubleshooting and will be able to fix the problem. There are times, though, that you’ll need to contact the nearest HVAC company for reliable air conditioner support.


There are a number of reasons why your air conditioner could be working but not dropping the temperature in your home, ranging from basic problems like an improperly set thermostat or a dirty filter to more complicated situations requiring part replacement.


  • The Thermostat Has Been Set Inaccurately 

Check the thermostat settings first if your house is getting a little hotter than normal. Make sure the temperature is set to cool. Check the temperature setting to make sure it hasn’t been adjusted whether the thermostat is set to cool. 

Turn it back to cooling mode if it’s turned off, set to heat, or set for the continuous fan (sometimes clearly labeled “on”). Wait a few minutes after the machine has turned on before checking for cool air blowing from the registers. 

If it’s cold, there’s no need to worry! If not, proceed to the next step in the troubleshooting process: inspecting the air filter.

  • Filthy Filter

Your air conditioner may have an air filter in or near the indoor air handler assembly. When soil, pollen, and other airborne particles join the air handler machine, the filter captures them. 

It makes the system’s components cleaner and more functional, and it can also help keep the air in your home cleaner. 

A clogged air filter will obstruct airflow and cause your home to overheat. It may also trigger the machine to shut down entirely in serious cases.

If your thermostat is working properly but you still don’t have cold air, look for your system’s air filter, turn it off, uninstall it, and test it. 

If your central air conditioner still doesn’t cool your home after you’ve confirmed that your air filter is safe, you’ll need to search a little harder to find the source of the problem.

  • The condenser device is obstructed 

The condenser unit’s exterior features a huge outdoor coil that stretches the majority of the way around the unit. The coil is made up of a number of thin metal “fins” that are very closely spaced. 

A jammed or clogged condenser coil could be the cause of your air conditioner running but not dropping temperatures inside. The condenser fan pulls air into the outside device through the condenser coil to extract heat energy from your home while it’s working properly. 

Dirt, grass, and other airborne particles will clog the coil by accumulating between the fins. 

A dirty coil may result in lower energy efficiency, a loss of cool air at the registers, or, in the worst-case scenario, a full system shutdown or compressor damage due to overuse. 

Clearing dirt, properly vacuuming the coil with a brush attachment, or softly rinsing the coil with a hose are all options for cleaning the coil.

  • A heat pump that has been damaged

A heat pump resembles an air conditioner, but it contains additional components that allow it to cool and heat your house. 

It works similarly to an air conditioner’s condenser device in terms of ventilation and is susceptible to the same problems – dusty, clogged coils, freezing coils, refrigerant leakage, compressor malfunctions, and so on. 


Check the thermostat settings, the air filter, and the condenser unit for previously mentioned problems if your heat pump system isn’t cooling.

  • Frozen evaporator coil

An evaporator coil is part of the indoor portion of the central air conditioning system. If your indoor appliance is a refrigerator, the evaporator coil is located outside the furnace in its own drawer. 

The evaporator coil is located within the fan coil cabinet if the indoor device is a fan coil (typically as part of a heat pump system). Warm indoor air flows into the evaporator coil, which removes thermal energy and humidity. 

The air is then pumped back into your house, making it cooler and more relaxed. The below are symptoms of a frozen evaporator coil:


  • Frost is building on the copper refrigerant tubing that leads to the coil cabinet.
  • Insufficient ventilation
  • Increased energy costs
  • Condensate runoff near your indoor device is excessive.
  • Frost formation on external refrigerant tubing or the outdoor unit in serious situations
  • Leak in refrigerant

The chemical refrigerant is essential to the cooling process. It changes from liquid to gaseous shape as it passes through the system’s indoor and outdoor coils, drawing heat energy and humidity from indoor air and releasing it outside. 

A refrigerant leak can cause your AC system to stop blowing cold air, operate for longer periods of time without properly cooling your house, or cause a damaged or faulty compressor and full system shutdown, depending on the magnitude.


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Congratulations, you’ve found it! Superior Mechanical Services, Inc. began in 1948 as a family-owned business with a vision to provide value-minded service with a down-to-earth approach to customers throughout the San Francisco Bay Area. As the premier Commercial and Residential HVAC repair company for Livermore, Dublin, and Pleasanton, Superior Mechanical can do it all, from heating and air conditioning services to boiler services, to plumbing services. Our AC repair technicians are certified professionals who will ensure every part of your project is done right using a careful checklist to guide and test each step. At the end of your appointment, we’ll show you how to get the most out of your system and give you tips on maintenance so it lasts for years to come. Contact us today for amazing service tomorrow!

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