Why Isn’t Your Air Conditioner Cooling Properly?

With blazing summer heat about to roll in, the dire need for optimal home cooling is more important than ever for homeowners. Air conditioning offers more benefits than simple comfort; it can also provide increased safety and better quality of life in your home. But what if your central air conditioner isn’t cooling your living space to the desired temperature?

There are several factors that can cause your air conditioner to not cool your home properly — or perhaps blow out lukewarm or hot air. Here, the heating and air conditioning experts at Custom Air Systems discuss the most common reasons for this and how to fix the issue.


Thermostat set to “on”. Is your air conditioner blowing out cool air at certain times of the day and lukewarm air at other times? If so, the fan setting may be set to “on”, which compels your system’s fan to run continuously regardless of whether or not your home is undergoing a heating or cooling cycle.

The simple solution to this slight complication is to set the thermostat to “auto”. When the fan setting is set to “auto”, your system’s fan will only run during heating and cooling cycles. Once the desired indoor temperature is reached, the fan shuts off automatically until the next cycle.

Clogged air filter. If your air conditioner isn’t cooling, it’s possible that the air filter is clogged. An air filter caked with dust, dirt and other debris reduces airflow to your air conditioning unit, resulting in issues such as the air conditioner struggling to circulate sufficient cool air to achieve the desired temperature. An example of this would be if your thermostat is set to 74 and your temperature fails to drop below 80.

Another problem that arises from a filthy air filter is frozen evaporator coils. This component assists in cooling the air. If it freezes, it will turn into a chunk of ice that then blocks the air. This means your home will only receive a limited amount of cooled air.

Be sure to check your air filter regularly. As a general rule, you’ll want to replace the air filter in your AC every three months. If you have pets running around the house, it’s best to change your filter at least once a month due to all the pet dander that will accumulate.

Insufficient coolant. Every air conditioning system needs a cooling agent that actually produces a cooling effect. The coolant circulates through the evaporator coils and proceeds to cool the air flowing over it. This treated air is eventually sent into each room in the house. If the level of the cooling agent becomes too low, it will take a long time for your home to cool off. With high temperatures outside, this can become particularly problematic. For one thing, the temperature you set won’t be reached, forcing the residents to endure an uncomfortable indoor environment. It will also cause your utility costs to skyrocket in the process.

If you think that your air conditioner is low on coolant, call a certified technician for a refill. Running your air conditioning unit in this state can damage the compressor beyond repair.

Dirty coils. In an air conditioning system, a condenser is an outdoor unit that dissipates heat removed from the interior space. If your air conditioner isn’t producing enough cooling, the condenser coils may be dirty and chock-full of debris. Condenser coils are located outside, so they’re exposed to dirt and other elements from the natural environment. In order for the condenser to carry out its function effectively, the condenser coils should be clean and free of blockages. As the coils get grubby and loaded with leaves, twigs and other debris, the air conditioner becomes less efficient, making it difficult to amply cool the living space.

To clean the condenser coils, simply spray the unit with a garden hose on a low setting. Blasting it on a high setting is a definite no-no, as this can bend the fins that allow the condenser to cool off. Don’t forget to remove any weeds or vegetation growing around the condenser as part of its maintenance routine.

Faulty compressor. Often called the “heart” of the air conditioning system, the compressor is a critical component in cooling your living space. It compresses the coolant or refrigerant and moves it between the evaporator and condenser coils. If there’s slugging or other technical problems with the compressor, this will put a halt to the cooling cycle and the air conditioner will fail to blow out cool air.

If you suspect that your compressor is defective, experts highly recommend calling a local HVAC installation contractor to diagnose the root cause of the problem and possibly install a new compressor.

High atmospheric temperature. Your air conditioning system has an optimal operating temperature at which it operates most effectively. If the surrounding temperature spikes beyond this optimal level, the efficiency of your system will be greatly affected. In some cases, the outdoor environment is so blisteringly hot that a phase is reached where the compressor stops functioning completely.

Undersized air conditioner. One of the most common mistakes that homeowners make when choosing an air conditioning system is purchasing a unit based on their budget and not on the specific requirements of their home. If your air conditioner is undersized, it will take too long to cool your living space, forcing it to run for an extended period of time. This means it will draw unnecessarily high amounts of electricity, resulting in inflated energy bills over time, and accelerate the wear and tear of different components.

According to HVAC installation specialists, the size of your air conditioner should be based on the size of the space to be cooled. This will allow it to properly alternate between periods of active cooling and periods of rest.

Defective parts. In addition, a defective compressor, a faulty run capacitor of the compressor, bad thermistor, broken-down control board, choked capillary and damaged motor are other possible technical reasons your air conditioner isn’t cooling sufficiently.

Faulty remote control. There can also be circumstances where the air conditioner remote fails to send signals directing a temperature change to the air conditioning unit. First, confirm if the display on the remote is working. If it isn’t, a simple replacement of the battery will likely solve the issue. If it doesn’t, replacing the remote control may do the trick. Fortunately, there are a few brand-specific and universal remote controls you can get from reputable sellers.

Contact Us for All Your Heating and Cooling Needs

Keep your living space cool, fresh and pleasant this summer. Custom Air Systems is a premier source of heating, ventilation and air conditioning solutions for residential and commercial properties. Whether you need to install new, energy-saving units or perform a tune-up, repair or maintenance on your existing equipment, we’ve got you covered! Our experienced technicians deliver industry-leading products and outstanding customer service to ensure the comfort and satisfaction of each and every client. Call us at (281) 426-0067 or fill out our contact form to request a free, no-obligation estimate. We serve in Manvel, TX, and other surrounding areas.