This leads to icky moisture problems and hot indoor air if you have some other form of exhaust, like a chimney for attic exhaust. Avoiding negative pressure also improves air quality by reducing outdoor pollutants that filter the home.

The best way to avoid all these problems is by using an active cooling system with an outside condenser.

But some people ask how many hours the AC should run per day. There is no clear answer to the question because several variables and factors influence how long your air conditioning unit needs to run per day. However, we will cover some general rules, so you can decide what's right for you and your home.

General Rules To Run AC Per Day

General Rules To Run AC Per Day
Here are some general rules that will help you to make the right decision which is best for you and your home because the more you run your AC, the more your electricity bill comes:
  • If daily highs and lows are between the 80s and 70s, turn on the air conditioner for two hours each day.
  • You can use Eco mode on air conditioning.
  • If the summer temperatures are in the low 90s and the lows are in the high 70s, use the air conditioner for four hours each day.
  • If daily highs and lows are in the high 90s and low 80s, use an air conditioner for eight hours daily.
  • If the minimum temperatures are in the higher 10s and the lows are in the 80s, run an air conditioner for 12 hours daily.
  • If highs are constantly above 120 and lows are in the high 90s or even 100s, run an air conditioner nonstop for 24 hours.

Note: The government does not determine these running timings. It's only a rough guess based on how many hours per day most homeowners operate their air conditioners during the summer.

Factors That Affect AC Run Time

Several things influence the frequency and duration of your AC unit's operation. The following are the key factors:

Types Of AC

Air conditioners come in three varieties: window, central, and portable. Depending on the model, you need to operate an AC for a specific number of hours per day:

  1. Central AC

The central AC is more reliable than other AC as it cools down the whole house. It uses less energy than other air conditioners, so you don't have to operate it as long as other air conditioners. Generally speaking, to maintain comfort, a central AC should be turned on for roughly 8 hours every day.

  1. Window AC
A window air conditioner reduces the temperature in a single room in your home. It would help if you operated it for longer than a central AC because it is lesser energy-efficient. You should usually operate a window air conditioner for 12 hours each day to stay comfortable.
  1. Portable AC

A portable air conditioner provides cooling for a certain room or area. You must operate this type of air conditioner for the maximum hours because it uses the least energy. Generally speaking, a portable air conditioner should run for roughly 16 hours daily if you want to stay comfortable.

Oversized Unit

If your air conditioner runs for intervals, mostly less than 15 to 20 minutes, and cycles on and off more frequently than four times per hour, it's probably too big for your house.

This is known as short cycling, when the air conditioner cools your house too fast. When this occurs, your home's AC system cannot dehumidify it as much as it should, keeping you uncomfortable and sticky.

Undersized Unit

But on the other side, if the air conditioner is very small for your house, it will be unable to properly cool and comfy your home. Undersized air conditioners frequently operate without touching the thermostat's set point for extended periods.

Your AC unit may be too tiny for your home if it's been running for 20 to 30 minutes or more without the temperature changing.

Insulation Quality

Insulation is crucial both in the summer and the winter. Your home's interior air will remain warm during the winter and cool during the summer, thanks to good insulation.

Your home's conditioned air will blow outside if you don't have enough insulation, which will negate the work of your AC unit. Of obviously, this makes it run longer.

Insulation Quality


What occurs when an AC unit runs too long?

The pressure in the evaporator (cooling) coil will decrease due to this continuous running until it freezes over. This is hazardous because the freezing could result in a flood of liquid refrigerant that harms the compressor. Moreover, you cannot afford to replace the compressor because it is a costly component.

Which setting is ideal for AC in the summer?

Keeping your air conditioners on "Auto mode" is the major strategy for dealing with such unexpected weather. The air conditioner will adjust the temperature and fan speed depending on the outside temperature.

Why does the Air Conditioner consume so much power?

The refrigerant within the evaporator coil evaporates to produce a gas, which is then recycled back into the compressor to force cool air all over your home while releasing heat into the outside environment. In this way, this complex system consumes a lot of electricity to operate, and the cooler the area you want, the more electricity bill you have to pay.

How can I lower my AC energy costs?

As air conditioners consume a lot of electricity, we have decided to write some easy suggestions; you may use them to reduce your electricity bill.

  • Select the appropriate setting.
  • When not using it, turn the power switch off.
  • To minimize overusing, a timer is required.
  • Regularly examine your air conditioner by a professional.
  • Lock all the windows and doors.


We are at the end of the article on how many hours they should run per day. Unfortunately, this is unclear because there are various causes and variables to keep in mind, like AC types, insulation quality, unit size, etc.

But we have written some general rules to help you make the right decision according to the weather conditions. However, setting your AC in auto mode is the best approach. We hope that this article will be helpful for you. Thanks for reading!

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