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Two air conditioner units outside brick home. Service industry, construction industries.

Is My Air Conditioner Running Too Long?

As the Utah summer heats up, you may notice your air conditioner running longer than usual. Is that normal, or does the system have a problem? To help answer this question, learn more about air conditioning cycles and the factors that could cause an AC unit to run too long.

5 Questions to Ask if Your AC is Running Longer Than Usual

Under ideal operating conditions, AC units should run for about 15 to 20 minutes before shutting back off. In mild weather, the cycles might be a bit shorter than this. Keep in mind that running for less than 10 minutes isn’t ideal because the air conditioner can’t dehumidify properly. This is called short-cycling, and it could signal that your air conditioner is oversized.

But what about when air conditioning cycles are too long? Is that a problem? Answer these five questions to help you decide.

What is the outdoor temperature?

The hotter it is outside, the longer your air conditioner must run to reach the desired temperature. Don’t be alarmed if cycles last longer than 20 minutes on a 95-degree day, especially if it’s also humid outside. It’s normal for AC units to run longer under these conditions.

What is the thermostat setting?

The lower you set your thermostat, the longer your air conditioner must run to maintain it. You may enjoy feeling as cool as possible, but adjusting the thermostat by just a couple of degrees can decrease your AC’s run time, lowering your electricity bills in the process.

Set your thermostat to 78 degrees in the summer. If you feel a bit warm, try removing a layer of clothing or turning on a fan. Airflow creates a wind chill effect that makes the room feel 4 degrees cooler. Then, set the temperature back 7 to 10 degrees when you leave for work to save energy while you’re away from home. Be aware that the AC will run longer than usual during the recovery cycle as it resumes a comfortable temperature.

Are you staying comfortable?

Taking outdoor temperatures and thermostat settings into account, it’s not surprising that some air conditioning cycles may be longer than 15 to 20 minutes this summer. The important thing is that you stay comfortable. As long as your AC unit reaches the target temperature in a reasonable timeframe, you probably have nothing to worry about.

Are your energy bills about the same as last summer?

It can be hard to tell whether your air conditioner is running more than usual—until you see your energy bills. Your utility provider should disclose the cost per kilowatt-hour (kWh) and your total energy consumption for the month. Compare this to the same month last year, keeping the average outdoor temperature in mind. If your costs are comparable, there’s probably not a problem.

How’s the airflow from your vents?

Place your hand over the supply registers throughout your house while the AC is running. Does the airflow feel nice and strong? Is the temperature refreshingly cold? If so, these are good signs that your air conditioner is functioning properly.

When to be Concerned About an Air Conditioner Running Too Long

Longer cycles can be positive because they help dehumidify your home and decrease the wear and tear associated with short-cycling. However, sometimes an air conditioner running too long signals a problem. You should be concerned if:

  • Your air conditioner runs for hours at a time.
  • The air conditioner never reaches the temperature you set on your thermostat.
  • You always feel uncomfortable in your home, no matter how long the AC runs.
  • Your energy bills have skyrocketed despite your comfort problems.
  • The airflow from your supply registers feels weak or warm.

If these problems sound familiar, consider the possible causes and how to resolve them.

Your air conditioner is undersized.

As discussed, oversized air conditioners are problematic, but so are undersized units. If your cooling needs are higher than the AC can handle, it won’t keep up on the hottest summer days. The only solution is to replace your air conditioner with a unit sized according to your home’s square footage, orientation, insulation levels, airtightness, interior heat gain, and other factors.

The airflow is restricted.

Perhaps your air conditioner is running too long because the cooled air can’t reach its destination. If you detect poor airflow from your registers, follow these steps:

  • Change the air filter.
  • Open all supply registers, even in unused rooms.
  • Make sure no return registers are blocked by rugs, furniture, or curtains.
  • Hire an HVAC technician to test your ductwork for air leaks.
The refrigerant charge is low.

Refrigerant is the key to air conditioning. If the system runs low, the air blowing from your vents may start to feel lukewarm. Watch out for ice forming on the indoor evaporator coil, a sure sign of low refrigerant. Only a qualified technician can detect and repair refrigerant leaks, so schedule AC repair if needed.

The evaporator and/or condenser coils are dirty.

Dirty coils are another cause of warm airflow and a constantly running air conditioner. Check your outdoor unit to see whether the condenser coils could use a cleaning. Gently spray the coils down with a garden hose to remove built-up dirt and debris. However, consider leaving evaporator coil cleaning to a professional to avoid damaging this delicate component.

Schedule Air Conditioning Services in Utah County or Washington County

If your air conditioner continues running too long despite your efforts to fix the issue yourself, it may be time to have a trained technician take a look. The experts at Triple T Heating, Cooling & Plumbing can troubleshoot the problem and recommend a cost-effective solution. Our goal is to keep you cool and comfortable this summer while keeping your energy bills down. To request an estimate for HVAC services, please contact us at 801-790-0460 if you live in Utah County or at 435-216-1608 for Washington County residents.