Is your home's air conditioner blowing warm air intermittently? While this isn't a rare or uncommon AC problem, there are plenty of possible reasons why your AC unit is blowing hot air.
It usually suggests something's not quite right with your air conditioner. Let's dive right into some of the most common issues why your central air conditioning system is blowing warm air (and what you need to do).
7 Causes of an AC Unit Blowing Warm Air
Here are some of the most common reasons your air conditioner is blowing hot air intermittently (when it should not).
1. Thermostat is Incorrectly Set
Yes, you read that right. Sometimes, your thermostat may be set incorrectly, whether you're aware of it (or not). If your AC starts blowing warm air, you may want to double-check the thermostat to ensure it isn't on heat.
You may also want to see if the thermostat is set to either auto or ON. The fan will continuously blow even if the air conditioner isn't cooling if it's set to ON. Your AC blows out warm air into your home when the outside unit vents aren't running.
2. There is an Airflow Restriction
There may be insufficient air from the vents if there's an airflow restriction to and from the AC unit. As a result, your air conditioner cannot adequately cool your home. A restricted airflow may also lead to the outside unit's compressor freezing up.
Generally, airflow restriction is a result of the following:
3. The Outside Unit is not Getting Power
Your AC system is composed of two main components: an outdoor and an indoor unit. The indoor unit holds the fan that blows air into the home, but it may only provide cold air if the outdoor unit is functioning well.
Once warm air blows out of the vents– the circuit breaker may have tripped, or the fuse may have blown on the electric circuit that supplies power to the outdoor unit. That said, have the circuit breaker or fuse panel checked by a professional to ensure the circuit is supplying adequate power to your outdoor AC unit. This will help you avoid dealing with significant issues.
4. Obstructed Condenser Unit
If the outdoor condenser unit is blocked or obstructed by leaves (or other debris) in the fall, your AC may also intermittently provide warm air. The condenser unit is responsible for releasing and collecting heat, depending on how you use your HVAC system for the season.
Once you notice intermittent warm air from your air conditioner, ensure that there are no obstructions on your outdoor unit. When left overlooked, it may lead to more costly AC repairs, which means more significant expenses on your end.
5. Blocked Registers/Vents
On a related note, your AC may also give off fluctuating warm air if the cooled air cannot get through the registers or vents. Ensure that every opening of your home’s central AC system is clean and clear, not blocked by several pieces of furniture.
6. Clogged Filter
Are you struggling to remember the last time you changed the filter of your central AC system? If that's the case, it may be time to change it. A clogged air filter can be why your AC unit blows intermittent warm air, as the system may struggle to push cooled air through the obstruction.
7. Central AC is no longer Efficient
Intermittent warm air may suggest it's time that you install a new AC system. This is especially true when the unit exceeds its average life expectancy and requires frequent repairs.
If the AC unit wasn't correctly sized for your home needs in the first place, you'd be better off with an appropriately sized AC system that provides more consistent cooled air.
Other Causes of Intermittent Warm Air from Your AC Unit
Most homeowners dealing with fluctuating warm or hot air issues with their AC unit are likely to be dealing with a compressor or outside unit problems. In some cases, the issue points to an air conditioner low on refrigerant. Other possible causes include a broken or disconnected return duct, which pulls in unconditioned air. All these issues can be handled by an HVAC repair professional. (Related: Seven Common Problems In Your Home’s AC System That Would Cause It To Blow Warm Air (With Solutions))
When to Seek an AC Professional for Help
Here are some issues to be mindful of, which may require you to contact a local HVAC repair professional.
There are no good reasons for your air conditioner to break, but having it start blowing hot air when you least expect it on a hot summer day could be the worst.
Keep in mind that an AC unit is not supposed to blow warm air on an intermittent basis. Contact a local HVAC professional at once when you notice that your AC unit is not evenly circulating cool air (like it's supposed to).