Why Is My AC Blowing Warm Air?

Why Is My AC Blowing Warm Air?

It seems like it was just yesterday that spring had finally sprung. But already, temperatures in Chattanooga have already reached 80 degrees Fahrenheit and higher. If you haven’t done your spring HVAC tune up yet, you may now be surprised to discover your AC blowing warm air.

Home repairs can sometimes be costly and time-consuming. That’s why it’s so important to perform a spring inspection before it starts to get hot. The good news is that troubleshooting AC that’s blowing hot air is a simple process.

Reasons Your AC is Blowing Warm Air

To figure out why your air conditioner is pumping hot air into your home, check the following common reasons:

1. Thermostat

This seems like a no-brainer but make sure that your thermostat isn’t set to “heat.” The transition from spring to summer can be a rollercoaster, and someone in your household may have switched it back to heat.

Then, make sure it’s been set low enough to trigger cooling. Air conditioning only switches on when the thermostat detects temperatures in your home higher than the set temperature. If you turn on the fan without the AC running, you’ll often just get warm from the vents.

And if you didn’t perform a spring tune up, the thermostat battery may be dead. That means it’s not detecting the rising temperatures in your home and not triggering a cooling cycle.

2. Power supply

Another reason your AC might be blowing warm air is that the circuit breaker to the condenser or evaporator has blown.

Your outdoor unit trips the circuit when debris or insects short out the equipment. The indoor unit can cause a surge in demand, tripping the breaker. Check your electrical panel to see if it’s the source of the problem.

3. Frozen coils

The evaporator coils in your indoor unit may freeze when clogged with dust or hair. If you haven’t changed the air filter regularly, this is likely to happen. Homes with pets and heavy traffic in and out exacerbate the problem, as does extremely humid weather.

If the coils are frozen, you’ll need to let them defrost completely before turning on the unit again. Change the filter while you wait and make sure the condensate pan and drain line are clear and remove the water. There will be a lot of it.

4. Blocked condenser

Another cause for hot air when the system is set for cooling is a blocked condensing unit. Your outdoor condensing unit can become clogged with dirt, debris, and vegetation. It needs space – at least 2 feet all around – to perform its all-import job of heat transfer.

5. Busted ductwork

Another reason for your AC blowing warm air is a gap in the ductwork. Attics get hot in the summer, and many homes have the majority of their duct runs in them. Any leaks or gaps can pull hot air from the attic into the ducts and out through the vents.

Check the ductwork in your attic for signs of gaps or holes. Look for damage from water or pests. Both damage the insulation on your ductwork and completely destroy fiberboard ductwork.

Make sure it is still well supported and none is sagging or falling down. If necessary, patch ductwork leaks and gaps temporarily with aluminum tape until it can be fixed properly

6. Refrigerant leak

If none of the above scenarios seems to be the problem, it may be a refrigerant leak. Your AC is meant to be closed-loop, which means all of the refrigerant should be contained within the system at all times.

Refrigerant chemicals are a hazard, and any potential leaks should be investigated by a trained HVAC technician. While there are many DIY fixes that many homeowners can perform, this is not one of them.

Your technician should find and fix the source of the leak before charging the refrigerant. Charging the system without finding and repairing the leak is unsafe and a waste of your money.

7. Blown compressor

We all get old and tired, and the compressor on an HVAC system may have simply reached the end of its useful life.

A faulty compressor means that the refrigerant isn’t been compressed enough to absorb or release heat adequately.

Replacing or even fixing a bad compressor is another one of those HVAC tasks best left to a professional.

If you’ve run through the first five reasons without a resolution, it’s time to call in a professional. Make an appointment today with the experts at One Hour Heating & Air Conditioning in Chattanooga. From ductwork repair to system replacement, we’ll restore cooling comfort to your home.