Summer’s heating up outside, but inside your home it feels like a meat locker. Your air conditioner is blasting cold air 24/7 but just can’t seem to get the temperature down. What gives?

Having an AC that runs nonstop is not only annoying but drives up your electricity bill. In this post we’ll go over some of the top reasons your unit might get stuck in overdrive and how to stop it.

Reasons Your AC is Running Constantly

Before you panic and call the AC repairman, take a minute to go through this list of common causes for an air conditioner that refuses to shut off:

The Unit Is Too Small

This is probably the number one reason an AC runs continuously without ever switching off. When an air conditioning unit is undersized for the space it’s trying to cool, it’s like trying to empty the ocean with a thimble. It will just keep going and going without making much progress.

Upgrading to a unit with more capacity suited for the size of your home is the ultimate solution. But there are steps you can take to limp along with an undersized AC in the meantime, which we’ll get to later.

You Need a New Air Filter

When airflow gets restricted because your filter is clogged with dust, pet hair and other gunk, your AC has to work harder to keep pushing air through. All this strain can cause the unit to run excessively.

Be sure to check your filter each month during heavy use season and replace it as needed. Don’t let it get so coated with debris that you can barely see through it!

The Coils Are Dirty

The evaporator coils inside your home and condenser coils outside can accumulate dirt and pollen over time. When this happens, heat transfer gets compromised.

Your AC will run and run trying to exchange heat but the coils have become so coated and insulated that it becomes impossible. Calling an HVAC technician to clean the coils can get cooling performance back up.

Refrigerant Leaks

Your AC system relies on refrigerant to cool your home. If refrigerant levels get too low due to a leak, the unit can’t cool properly and must run continuously to come close to reaching your desired temperature.

Refrigerant leaks require repair from a professional. Low refrigerant also reduces the lifespan of the compressor.

Thermostat Malfunction

If your thermostat is incorrectly calibrated or malfunctioning, it may never signal your AC to turn off. The system will continue running even after the desired temperature is reached.

Faulty thermostats need to be repaired or replaced. A professional can determine if an issue exists.

Short Cycling

Sometimes an AC unit will turn on and off repeatedly in short bursts rather than running longer cycles. This is called short cycling, and it prevents proper moisture removal from the air.

Short cycling often indicates an oversized AC unit or a problem with the refrigerant charge. It leads to lower efficiency and constant operation.

Failing Capacitor

The capacitor helps start your AC’s compressor and fan. If it fails, the compressor may have trouble turning on fully and will run constantly trying to start.

Replacing a bad capacitor is inexpensive compared to the cost of running an AC unit continuously due to the issue.

Solutions for an AC That Runs All the Time

If your AC is staying on for too long, take these steps to troubleshoot the issue:

Check Air Filter

Your first move should be replacing or cleaning the unit’s air filter. A dirty filter is the most likely cause of continuous operation.

Turn off power to the unit, remove the filter, and either spray it clean or insert a new one. Air should flow through easily.

Clear Coil Debris

Use a hose on gentle setting to spray off outdoor condenser coils if they have dirt buildup. For indoor evaporator coils, you’ll need a technician to clean thoroughly.

Make sure no leaves, dust or other blockages remain. Proper airflow and heat transfer depends on it.

Look for Refrigerant Leaks

Signs of low refrigerant include reduced cooling, higher utility bills, and constant running. Have an HVAC pro inspect for leaks.

Repairing leaks properly requires evacuating refrigerant lines, sealing leaks, replacing lost refrigerant, and testing operation.

Check Supply Vents

Make sure all supply vents are open and that air flows properly throughout your home. Closed vents lead to short cycling and limit cooling.

Examine the Thermostat

Verify thermostat operations manually with an additional thermometer. If temperature readings are off, replace old thermostats with a new smart model.

Consider Unit Replacement

For older AC units, replacement may be the most cost effective solution. Newer systems are far more efficient.

Work with an HVAC company to determine if replacement will pay for itself in energy savings over time.

Schedule Professional Maintenance

Have an HVAC technician perform biannual maintenance to check for issues. They can verify refrigerant levels, coil conditions, capacitors, and other components.

Routine maintenance helps minimize expensive repairs and keeps your system running efficiently.

Prevent AC Problems With Proper Sizing

To avoid constant operation long-term, make sure your AC unit is properly sized for your home. A mismatch is the most common cause of inefficient cooling.

Here are tips for getting the right system size:

• For new AC installation, work with an HVAC pro to match unit capacity to home square footage. Get professional load calculations.
• When replacing an existing unit, look for similar capacity measured in BTUs/hour. Avoid dramatic upsizing or downsizing.
• Consider not just home size but orientation, window area, insulation, and other cooling demands.
• Install Energy Star certified systems with a high SEER rating for efficiency.
• Get quotes from multiple contractors to compare recommendations.
• Consider a multi-stage system that can operate at lower capacity on milder days.

Properly sizing your AC unit will allow it to maintain comfort without having to run continuously. You’ll save on energy costs while avoiding premature system wear.

Take Action to Stop Constant AC Operation

The next time your AC stays on for hours on end without ever shutting off, use the tips in this article to troubleshoot the issue. In many cases, basic maintenance is all that’s needed to solve the problem.

Catching small problems early can prevent expensive breakdowns down the road. And stopping constant operation keeps money in your pocket on utility bills.

FAQs

Why does my AC run continuously even at night?

Air conditioners are designed to run until the desired temperature is reached. If your home retains heat at night or the unit is undersized, it may run nonstop trying to cool down. Try lowering the thermostat 5-10 degrees before bed to allow the system to catch up. Make sure your unit is properly sized for the square footage.

What happens if I turn my AC off at night?

Turning your AC completely off at night is not recommended. With hot outdoor temperatures, indoor humidity can spike as your home warms up. This makes cooling even more difficult when turning the AC back on. Set a higher temperature instead of fully turning it off.

Can running my AC constantly cause it to freeze up?

Yes, constant operation can potentially lead to frozen air conditioning coils. This happens when coils get too cold from nonstop runtime. Air can’t flow over frozen coils, forcing the AC to keep running while providing little cooling. Be sure to change filters, clear debris, and service your unit regularly.

Is it normal for my new AC to run all the time?

A new, properly sized AC may need to run continuously for several days to remove built-up heat from your home’s walls, furniture and floors. This stored heat gets released gradually. Once your home is cooled down, new units should cycle on and off normally.

Does continuous operation mean my AC is too small?

Not always. An undersized unit is one of the most common reasons an AC runs nonstop, but other factors like poor insulation or tight ductwork can also cause it. Have an HVAC technician evaluate your home’s cooling needs before assuming unit size is the issue.

Can I damage my AC by running it continuously?

Excessive run times strain the components of an AC system, potentially leading to early failure. The compressor, evaporator coils and other parts endure more wear and tear with constant operation. Proper sizing, maintenance and prompt repairs reduce the risk.

Should I turn my AC off for part of the day to reduce runtime?

No, turning your AC on and off repeatedly can cause further strain. It’s best to maintain a constant temperature when possible. If you’ll be gone for more than 4 hours, then you can adjust the thermostat higher to reduce runtimes.

Is a new AC really worth it if my old one runs nonstop?

Replacing an aging, inefficient AC with a new ENERGY STAR model can definitely be worth it, saving you money on utility bills in the long run. New units run fewer hours per day due to increased efficiency. Just be sure your contractor sizes the new system correctly.

Can I add a second AC unit as a quick fix?

Installing a second AC unit may seem like a quick way to boost cooling, but it often causes new issues. Total capacity of both units still needs to match your home’s needs. Two units can lead to uneven cooling, humidity issues, and frozen coils. A new correctly sized unit is better.

Does continuous operation mean there’s a refrigerant leak?

Sometimes, but not necessarily. Low refrigerant from a leak makes cooling less efficient, requiring longer run times. But many other problems like dirty filters or improper sizing cause AC units to run nonstop as well. A technician can determine if refrigerant levels are too low