A person with their hands on the temples of their head sweating

8 Reasons Why Your Air Conditioner is Blowing Hot Air (Fixes)

Meet Sean. Sean just came home from a solid day’s work on a sweaty, Florida summer day. He’s thrilled to enjoy an ice-cold beverage in the peace, quiet, and comfort of his Florida home. But, when he turns on the switch, he realizes his air conditioner is blowing hot air.

And in the middle of the day in 100-degree weather, the words “cool” and “comfortable” couldn’t be farther away in Sean’s mind. He’s going to have a long night ahead of him.

Florida residents: if you’ve ever been in Sean’s shoes, you know what it’s like to experience the sweltering, muggy heat of our Florida climate. With an air conditioner blowing hot air, you might be out of luck using “cool” and “comfortable” in your vocabulary in a situation like Sean’s.

“So, why exactly does an air conditioner blow hot air?” you might wonder. We’ve got your back.

After more than 20 years of installing, repairing, and maintaining air conditioners in the Sarasota, Florida region, we’ve found eight common reasons why an air conditioner blows warm and hot air.

If you’re wondering why an air conditioner blows hot air, continue reading on, as we explore the eight most common reasons why an air conditioner blows hot air.

Why an air conditioner blows hot air (8 common reasons)

1. Thermostat issues
2. Tripped breaker
3. The air conditioner lines are clogged and water has built up
4. The air filters are dirty and need cleaning
5. Low refrigerant levels in the air conditioner
6. Issues with the compressor
7. Outdated parts and/or malfunctioning parts
8. Duct leaks

Reasons why air conditioners blow hot air

An air conditioning unit on top of a building facing a large body of water

In general, an air conditioner may not function because of issues that occur in five main parts in the HVAC system, including:

  • Clogging issues
  • Electrical problems
  • Refrigerant fluid
  • Evaporator coils
  • The air compressor

Proper air circulation across these parts is key to ensuring the comfort, health, and safety of your indoor air. Let’s take a look at eight ways in which these components can cause air conditioners to blow hot air.

1. Your air conditioner thermostat is acting up

A Nest thermostat on a wall

Before calling a professional to look at an indoor air unit, you’ll want to check a few basic aspects. Sometimes, fixing the issue is about checking the thermostat.

First, check to see that your temperature is set below the current air temperature, set the dial to “heat,” and if you have a zoned system, check both thermostats.

Also, make sure your thermostat is set to “Auto” and not “On.” The “On” setting refers to the fan being on, not necessarily cold air blowing on through the air conditioner. If the issue isn’t related to the thermostat dial, the issue could also be in the thermostat’s batteries.

If replacing the batteries don’t fix the issue, the thermostat could be malfunctioning. If you’re still having issues, consider reaching out to an HVAC installation and maintenance crew to determine if your thermostat needs to be replaced.

2. A tripped breaker could be the issue

An air conditioner on the Florida coast with the water and buildings in the background

Another possible reason why an air conditioner might be blowing warm air is because the breaker switch could have been tripped. What’s more, the outdoor condensing unit might be powered off.

You can fix a tripped breaker by peering in the circuit box. If the circuit box has tripped, flip the switch back, and check the air temperature again.

If hot or warm air continues to blow, you may want to give your local HVAC professional so they can troubleshoot the issue.

3. Clogged A/C lines and water buildups

An air conditioner repair person working on clogged air conditioning lines

Since every air conditioner produces water making the warm air flow cold, an air conditioner also uses a drain system to rid of the warm air. We call drain systems condensate drain lines or condensate lines for short.

If the hose or condensate lines become clogged, the lines can leak water. Most units have a safety mechanism that causes the air conditioning compressor to shut down.

Since the air conditioning compressor is responsible for transferring heat from the refrigerant to the condenser and condensate lines, if the A/C compressor isn’t working, your air conditioner could begin blowing warm air.

Consider keeping your condensate lines clean to help your A/C unit blow cold air at full force.

4. The air filters are dirty and need cleaning

An air filter shown on an air conditioning unit on the inside of a home garage

Dirty air filters can create huge problems for an air conditioner. If airflow is restricted or affected by dirty or clogged filters, the A/C’s motor, fan, and compressor can be affected.

For example, fans, compressors, and motors must invest more effort to ensure the flow of cool air indoors. If left untreated, dirty air filters can even cause an A/C system to freeze, as the evaporator coil will be affected.

On the flip side, replacing air filters often can ensure consistent, unrestricted airflow that helps your HVAC system perform at its best.

Did you know?

A "before" and "after" picture of an air filter with a can of gloss protective enamel next to the filter.

If you see a rusty one of these on your outdoor air conditioning system, lightly wire brush and paint them. Painting these will prevent refrigerant leaks and help you prolong the life of a filter drier.

For more tips and tricks about air conditioning systems, check us out on Facebook!

5. Low refrigerant levels could be the culprit

An air conditioner repair person finding the source of refrigerant leaks on an indoor air conditioning unit

Refrigerant refers to the agent that facilitates the heat-cold exchange in an A/C system. Low refrigerant levels can cause a system to cool less.

As a result, the air conditioner may not blow cold air as well. When an air conditioner’s evaporator coil becomes dirty or leaks, the coil won’t perform the necessary processes to transfer heat and keep the circulated air cool.

The result? The potential for more leaks, less comfort, higher electricity bills, and potential problems for an air conditioning system.

If low-level leaks occur, the leaks can damage parts of the air conditioner and heat pump. Because the heat pump and air conditioner must invest more effort to keep the air cool, the machinery in the A/C system can degenerate, causing premature wear and tear to the air conditioner.

If you need to recharge refrigerant fluid, you’ll want to speak with an HVAC pro, as doing so can be challenging. Having the right R-22 or R-410A refrigerant — as well as the equipment to check that the refrigerant replacement goes off without a hitch — is paramount to ensuring refrigerant replacements go as planned.

Reach out to your air conditioner specialist of choice around the spring or fall to conduct air conditioning maintenance for refrigerant fluid checks.

6. The compressor could be malfunctioning or restricted

A picture of a condenser on the outside of an outdoor air conditioner

A compressor is responsible for cooling the evaporator coil. If the condenser can’t compress the refrigerant that’s needed to keep the evaporator coil cold — and if the condenser isn’t working at full capacity to expel hot air outside — the coil won’t be cold enough to keep indoor air cool and temperate.

If you notice dirt and debris around the compressor, you’ll want to have a licensed HVAC professional inspect the cause of disrepair.

7. Condenser fan issues (and other parts issues)

A cat sitting on the outside of an air conditioner unit

Among other essential air conditioning parts is the condenser fan. The condenser fan sends heat from the evaporator coil outside.

If your fan isn’t working, the condenser will overheat. When the condenser overheats, the evaporator coil won’t process the warm air coming from your house with as much gusto.

Hence, even if your air conditioning is set to the “cool” function, you’d be hard-pressed to feel cold air blowing through your A/C unit.

What are some of the most common causes of a broken condenser fan? Rust, damaged bearings, and debris: each can stop the fan from rotating and working as it should.

8. Potential duct leaks

New A/C ductwork completed inside of a home

Ductwork helps keep the air in your home cool. But, when there’s a large leak, warm air can mix in the air ducts and find its way into the cold air being circulated indoors.

The mixture can result in hot or warm air blown throughout your property. To fix duct leaks, you should hire an air conditioner maintenance team to clean your air ducts every three years.

If your air conditioner blows hot air, call an HVAC pro

A picture of an orange-red sunset on top of a roof with air conditioners in the foreground

Though the solution to an air conditioner blowing hot air may be as simple as adjusting the thermostat settings, you can never go wrong with relying on a seasoned air conditioner repair team to check your central air unit.

Of the 50 contiguous states in the United States, Florida ranks number two (just behind California) for most HVAC and plumbing establishments per state (Statista, 2023). With that being said, if you decide to repair your HVAC unit, you’ll want to make sure you’re choosing a reliable company that offers comprehensive and reliable service.

At Streamline Air, we’ve been servicing the Sarasota, Florida region for all their air conditioner and HVAC needs for more than 20 years. If you need a quality HVAC service team that provides straightforward, simplified solutions, we’d love to know how we can be of service.

Contact us today at (941) 356-6872 for your zero-risk, complimentary quote on your next air conditioner repair. Until then, be well, and stay cool.

Meet the Straightforward Professionals at Streamline A/C!

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