AC Blowing Warm Air

AC Blowing Warm Air

Whenthe AC is blowing warm air, you can check for simple issues that may bethe cause. For example, a common cause for heating and air conditioning issuesis due to improper settings on the thermostat, typically the fan setting is onmanual run and the AC being off.  Inaddition, a tripped circuit breaker is a frequent cause of HVAC issues.Power surges are a fact of life, and are a common cause for tripped breakers.The following provides an overview of common causes of the AC blowing warmair.


First,check the thermostat settings, ensuring the thermostat is on cool, and the fanis on automatic. People often set the fan to manual run for various reasons,and turn the AC/Heat option to off. The result is the fan runs continuously,but the AC (or heat if it’s winter) will not cut on. As a result, it appearsthe AC is blowing warm air. In the winter, the heat will only blow coolair. 

However,if there is a problem with the thermostat, and it operates on batteries,replace them with new. This simple procedure may correct the problem. However,if repair or replacement is required, contact your HVAC technician.


Thenext step is to ensure the circuit breakers haven’t tripped. Especially if thesystem isn’t working at all. If a breaker has tripped, firmly push it all theway to off, and back on. Next, adjust the temperature to test the system forproper operation.


Refrigerant leaks are a common cause ofthe AC blowing warm air. When refrigerant is low or highproblems occur. People often make the mistake of thinking refrigerant is usedup as is the case with oil. Refrigerant is only lost when there is a leak inthe system.

Onesign of low refrigerant is icy refrigerant lines. A leak will require theservices of a qualified HVAC technician to provide both repair of theleak and recharging the system with the proper amount of refrigerant.


Overtime, the coils become dirty, this process will be accelerated if the airfilter is not routinely changed. Soiled coils interfere with the system’sability to perform properly and can result in the AC blowing warm air.  The air conditioning system, and a heat pump have an evaporator coiland a condenser coil. The locationof the coils will depend on the type of system you have. Coils may belocated  both inside and outside, or onlyoutside. Refrigerant is converted to a gas that absorbs heat in the evaporatorcoil. While it is in the condenser coil where the gas becomes a liquid andrelease the heat outdoors.

Thecoils require periodic professional cleaning to provide the proper performanceof the system. Routine annual maintenance of the system, and biannualmaintenance of heat pumps will ensure coils are cleaned before problems canoccur. Furthermore, it is effective in maintaining efficiency, preventing excessiverepairs, enhances performance and extends the unit’s lifespan.

Nevercut the grass with the mower discharge chute directed towards the outsidecondenser. Doing so will increase the need for condenser coil cleaning and runsthe risk of potentially costly damage from rocks and other debris.  


Abad compressor is the worst possible cause of the AC blowing warm air. The compressor is the heart of the air conditioning or heat pumpsystem, and the most expensive component. When a compressor fails and thesystem is 10 years old or older, the recommendation is typically a new air conditioning installation.

Cypress Heating and Air Conditioning offers residential and commercial heating and air conditioning services.Our NATE certified technicians ensure you receive the highest qualityservices available. You can rely on our technicians’ expertise to meet and/orexceed the industry standards. If your ACis blowing warm air, contact us for airconditioning repair Katy. We serve Katy, Plano and the surroundingareas, and are a member of the BBB with an A+ rating.