Does Your Home Air Conditioner Start Cold Then Get Warm?
Written By: Alexis Bennett
Edited by: Andrew Dunn
Is your air conditioner blowing cold when you turn it on, but over time it starts blowing warm air? Several things can cause that to happen.
So, we created a guide to help you troubleshoot this problem.
In this guide, you will learn:
- What are the reasons your home air conditioner starts cold then gets warm?
- What should you do if your air conditioner is blowing warm air?
- How can you properly maintain your HVAC to avoid system malfunctions?
- And more!
Your home air conditioning keeps you safe and comfortable. However, when your HVAC system starts having issues, it is incredibly stressful.
Luckily, there are some things you can do to keep your system running cold year-round.
What's In This Guide?
What Are The Most Common Reasons For Your AC Blowing Warm Air?
There are many reasons your air conditioner could stop running efficiently throughout the day. These are some of the first things you should check if you notice that your air conditioner is not blowing cold air.
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Incorrect Thermostat Settings And Malfunctions
The thermostat inside your home is like the brain of your air conditioner. It tells the HVAC system what temperature it needs to be in your home.
Basic thermostats have auto, on, fan, cool, and heat settings. Newer thermostats give users the ability to set the temperature to increase or decrease automatically at certain times throughout the day.
Thermostat Maintenance Tips
Check the settings on your thermostat periodically. You should also change the batteries regularly and wipe the exterior with a mild cleaner and a damp cloth to prevent dust from collecting inside.
You can also check to make sure the thermostat is properly connecting. There are prongs on the back of your removable thermostat face. If those prongs are missing or bent, it can cause the air conditioner to not work correctly.
Missing Or Dirty Air Filters
When the air filters get clogged, your system is not able to pull as much air into the air handler. That causes strain on the blower and other essential parts of your air conditioning system.
Missing filters are also a significant concern. When your system is missing air filters or the air filters are improperly installed, it allows dust, dirt, dander, hair, and debris into your air ducts and evaporator coils.
Keeping your evaporator coils clean is essential because dirty coils make it difficult for your air conditioner to cool air, and it can even cause your unit to freeze.
Air Filter Maintenance
Do you know when you last changed your air conditioning filter? If not, it is probably overdue.
Changing the air intake filters is the most beneficial thing you can do as a homeowner to extend the life of your HVAC system. Check out the list below to find out how often you need to change your filters:
- Vacation Home – 6 months
- Individual – 3 months
- Family – 60 days
- Family or Individual w/ One Pet – 45 days
- Family or Individual w/ Multiple Pets – 30 days
The EPA suggests that every homeowner change their air filters at a minimum every three months. However, not every homeowner should wait that long, and you should change your air filter as soon as you see that it is dirty.
Your air conditioner needs refrigerant to cool the hot air it sucks in from your home. If there is a refrigerant leak or your freon levels are low, your air conditioner will struggle to maintain the desired temperature.
Prevent Low Refrigerant Levels
You can prevent low refrigerant levels before they cause strain on your air conditioner by having your system maintained semi-annually. During the maintenance appointment, the technician will look over your entire system, including the condenser coils, outdoor unit, inside unit, ductwork, refrigerant levels, fan motor, and refrigerant line.
If there are any maintenance issues or if your HVAC unit needs more refrigerant, the technician will address those issues. Regular system checkups are important because many problems that cause major system failures arise when homeowners ignore routine maintenance.
Dirty or Damaged Ductwork
Ductwork plays an integral role in getting the conditioned air from your inside unit to each room in your home. When the ductwork is damaged, it can cause hot air to blow out of your air ducts.
Damaged ductwork puts a strain on various parts of your central air system and causes the room temperature not to decrease while your air conditioner is running correctly.
If you want to learn more about cleaning your air ducts, take a look at this video.
Properly Maintain Ductwork
When you have your central AC maintained, ask the technician to check your ductwork. They can’t see inside the ductwork unless they use a camera, but they can check the exterior for any damage.
It is also a good idea to have your air ducts professionally cleaned from time to time. Dust, dirt, debris, toys, and other items that accumulate in your air ducts can block cold air from getting through the vents.
Dirty Evaporator Coil Or Frozen Evaporator Coils
Evaporator coils are what coils the warm air in your home. The evaporator coils can get dirty over time. When your evaporator coils are dirty or frozen, the unit is unable to cool the air.
Check Your Evaporator Coils
Depending on the type of air conditioning system you have, accessing your evaporator coils could be challenging. However, you will first need to locate the inside AC unit.
Inside the unit, behind the air filter, you will find the evaporator coils. Check to make sure it is not damaged and that the exterior of it is clean and free of debris. If it appears dirty or frozen over, turn your air conditioner off and call an HVAC technician.
Electrical problems are another common cause of air conditioning malfunctions. If one of the components in your HVAC system is not receiving power, it could lead to your AC blowing warm air.
Fixing Electrical Issues
By your outside unit, there should be a circuit breaker box. The switch turns power on and off on the condenser unit.
When the circuit breaker trips, the outside ac unit will not turn on. If the fan is not turning, the system is not extracting warm air from your home, and the air temperature inside will rise.
If your outside unit is not turning on, you may need to call an electrician. It is always best to let a professional handle electrical work.
Final Advice When Your Air Conditioner Is Blowing Warm
Your HVAC is a complex system of components. Each piece has to run correctly for the system to cool your home’s air effectively.
Unfortunately, there is no way of knowing what could be causing your air conditioner to blow warm air without looking at the system and running diagnostic tests. So, if you try the DIY tips above and your air conditioner is still not blowing cold air, you should schedule a service call with a knowledgeable HVAC technician.
You may also want to invest in a home warranty plan from a top provider in your area to help you prepare for significant air conditioner repairs before they are necessary.