Why Is Your Heater Blowing When the Thermostat is Set to Cool

If it seems like your air conditioner is actually heating the air like the furnace does, you may need to change the HVAC settings, maintain it, or call for a repair. It’s not normal for cooling systems to blow hot air, and in most cases, it’s an easy fix to bring it back to normal.

Fan Setting

Check the thermostat’s fan setting. If it’s set to “on,” it’s possible that you could feel hot air coming from the ducts. Avoid these hot-cold cycles by setting the thermostat to “auto” so that the system turns off when the cooling cycle finishes.

Dirty Outdoor Condenser

When dirt covers the condenser coil or too much debris blocks the airflow through the condenser, the system won’t work as well. It should be clean and have at least three feet of clearance on all sides for adequate air flow.

Frozen Evaporator Coil

• When the air conditioner runs continuously and the HVAC settings indicate that fan is set to auto, you may have a frozen evaporator coil. The most common reasons include:
• Inadequate refrigerant. Over time, the refrigerant may leak from the system, even through a pinhole leak. The best way to prevent low refrigerant is by having your HVAC system serviced annually. A refrigerant check and refill is an important component of keeping your A/C running efficiently and dependably.
• Dirty air filter. Check the condition of the air filter when the air is blowing warm. Change if it’s clogged.
• Dirty coil. Sometimes dirty collects on the evaporator coil or mold grows over it. If you can access it, clean the coil using a soft brush. If it’s hard to reach, contact your HVAC contractor for help.

Ductwork Leaks

Unless you have many small ductwork leaks, it’s more likely you have a large leak that is bringing in hot air to the rooms that particular branch of ductwork serves. Contact your HVAC contractor immediately for emergency repair.

Most cooling problems stem more from maintenance issues rather than HVAC settings. For more information, contact Rinaldi’s Energy Solutions, providing HVAC services for Orlando-area homeowners.

Our goal is to help educate our customers in Orlando, Florida and surrounding areas about energy and home comfort issues (specific to HVAC systems).