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How Many Hours Should an AC Run Per Day?


Most people don’t know how many hours should an AC run per day. In this article, we will cover everything you need to know about air conditioner usage, so you can make an informed decision about how long your air conditioner should run each day.

How Does an Air Conditioner Work?

How Many Hours Should an AC Run Per Day?

Air conditioners keep our rooms cool by absorbing heat around the house and cooling it afterward. They serve a crucial purpose in indoor safety and comfort.

Here’s a three-step guide to understanding the process of an air conditioning system:

  1. The AC unit uses chemicals that convert gas to liquid and vice versa. These chemicals transfer the heat from the air inside your property.
  2. The evaporator coils absorb the heat and cool it with the refrigerant, which is stored inside the coil.
  3. A fan blows the cool air into the air filter, and the ducts distribute it throughout your home.

Factors Affecting the Hours an AC Should Run Per Day

Before you know how many hours an air conditioner should run per day, you will have to determine how long the unit takes to reach your desired temperature setting. It would be best if you run your AC for about 8 to 20 minutes per day to keep you comfortable. Here are the factors affecting the operating hours of AC units:

Type of Air Conditioner

Air conditioners come in many shapes and sizes, all with their unique pros and cons. There are three types of ACs: central, window, and portable air conditioners.

Central Air Conditioner

A central AC cools down the entire house. It is more energy-efficient than other types of air conditioners. You can run it for short periods, compared to other types of ACs. Some experts are suggesting that users should run a central AC for about 8 hours per day.

Window Air Conditioner

A window air conditioner cools down a specific room in your house. It is less energy-efficient than central AC. Therefore, you need to run it for more hours.

Portable Air Conditioner

A portable AC is the least energy-efficient type of air conditioner. Some are running their portable ACs for one whole day to keep the temperature cool.

Size of Air Conditioning Unit

The larger the air conditioner is, the more power it will use. An oversized AC unit can use as much as 1000W. To estimate how long your AC unit should run, figure out first the square feet of the space.

The U.S. Environmental Protection Agency suggested that the BTU required in one square foot is 20. Understanding this information allows you to select a properly-sized air conditioner for your room.

How Long Should an AC Stay Off Between Cycles?

The length of AC cycles primarily depends on the thermostat setting, with very low temperatures demanding longer cycles than higher temperature settings. After every cycle, the AC stops for a while before restarting to continue its cooling process.

Normal Cycle

Ideally, a performing air conditioner should cycle for roughly 15 to 20 minutes, two to three times per hour. However, the cycle it completes will depend on various factors, like the size of your home, outdoor temperature, and thermostat setting. 

Short Cycle

A short cycle, also called short cycling, indicates that the compressor keeps turning on and off in under 10 minutes. Since a regular cycle should last between 15 and 20 minutes, a 10-minute run is shorter than usual. If your air conditioning unit is only running for 10 minutes or less and for multiple times per hour, this can cause permanent damage to the compressor.

Long Cycle

Long cycles occur when your air conditioner does not have enough power to reach your desired temperature. Since the cooling cycles are longer than usual, it will certainly make your utility bills go through the roof.

How Long Should an AC Run Per Day?

Given the humidity and heat in the Philippines, it’s easy to feel hot and think about turning your air conditioning system on all day. You can either let the air conditioner run constantly or turn it off when you reach the desired setting. 

Run the AC Continuously

Keeping your AC unit running in long cycles might seem expensive, but it is much more cost-efficient than constantly turning it on and off. The tip here is to initially run your AC unit with a lower temperature to set the thermostat and continuously run it with a higher set point. With this, your air conditioner may have to maintain the temperature to avoid getting your home warm.

Keeping the AC turned on for 24 hours doesn’t mean it will run continuously for the entire time. This is because your air conditioner’s compressor goes in cycles after achieving the desired room temperature.

Turning On and Off

The energy required to get the temperature back within a set point will be greater than merely having the AC unit perform another cooling cycle to maintain the temperature throughout the day.

The performance of your AC unit, when turned off after a minute, will defeat the purpose of having an AC system. HVAC systems are designed to sustain the temperature, not to drop it quickly. Therefore, if you plan on running your AC unit for only quite some time, allow it to set the room at your desired temperature first for about 15 to 30 minutes.

Is It Normal For an AC Unit to Run All Day?

The short answer is yes, it is alright to have the air conditioner running for long periods, but it is best to just do this during hot summer days. 

However, there is a difference between keeping your AC on throughout the day and the compressor running all day. Once your space reaches your desired thermostat, your AC system, or the compressor, should stop running automatically. However, if you have the thermostat set to fan mode, the blower fan will constantly run – even when the AC isn’t cooling.

The standard procedure for the HVAC is to size the system so it must run continuously on your warmest days. This enables the AC to operate less frequently, better regulate the humidity, and maintain the temperature inside your home.

How Many Hours Should My AC Unit Run on a Hot Day?

We all bought our AC units to avoid getting consistently hot. It can be tempting to crank up your air conditioners the entire day to curb the high outdoor temperature despite the risk of a higher electricity bill. 

An AC unit removes the heat from the indoor temperature. Therefore, running it on hotter days equates to higher energy costs. Here are the ways to mitigate this problem:

Run the Air Conditioning System for 14 Hours per Day

With the increasing global temperature, it becomes harder to find time within the day to turn off your AC. It is possible to keep your air conditioner continuously running all day, thanks to the method called pre-cooling. However, this mode is only recommended to run within 14 hours per day. 

The main idea behind pre-cooling is that the lower the temperature is, the easier it gets to make the home cool. You can turn on the unit during midnights and let the AC run. When it gets hotter outside later in the day, you can adjust the temperature to where you truly want it and let the system run for a bit.

Pre-cooling is an excellent method for time-of-use electricity plans and cooling efficiency since it can only move so much energy in an hour. If the house is cooler, to begin with, the AC will work to keep up with the incoming heat at its set capacity. Still, the cooler beginning temperature leads to a cooler ending temperature. 

This works best in houses with adequate insulation and when blinds or curtains are drawn to block the sun. Countering outside heat and maintaining your desired room temperature is the aim of the game. Unfortunately, the AC will only be able to handle some of the heat flowing in if your home is well-insulated or sealed.

Run the Air Conditioning System for 8 Hours per Day

Keeping your AC unit running within 8 hours or less is only recommended for smaller rooms. This is to get your desired temperature without compromising more power consumption. With a smaller room size, short cycles will be enough for your AC unit to achieve a more comfortable temperature.

Cons Of Running AC Continuously

If your AC is always on, parts will wear out sooner, meaning a higher cost for repairs and, eventually, early system replacement.

Clogged Filter

Filters are one of the parts that are first to malfunction if your AC runs continuously. Due to the constant clogging of dirt, dirty filters will interfere with airflow inside your home, so it is best to change your filters regularly.

Dirty Coils

Dirt on a coil forms an insulating layer between the air and the refrigerant. This makes it much more difficult for the refrigerant to absorb heat, causing temperatures to rise.

Final Thoughts

10 Aircon Saving Tips: How to Save Money and Energy While Staying Cool

Ultimately, how many hours your air conditioner runs daily will depend on your needs. As the climate in the Philippines is exceptionally humid and hot, you may need to run your AC unit more often than someone who lives in a less extreme climate. 

The AC is designed to run for long periods. Of course, there is a limit to how long your equipment can operate before it breaks down, but keeping the set point low will reduce the amount of energy transfer required and the overall number of running hours for your AC.

Feel free to consult your HVAC technician to perform routine maintenance to keep your AC unit in tip-top shape.

JP Reyes

JP has been in the aircon industry for almost as long as he has been alive. As a child JP would help his tatay fix aircon units at their junk shop in Cavite. After graduating UP in the early 2000's, JP then started his own Aircon servicing business and within 5 years had 10 shops in 8 different cities. Fast forward to today and JP brings all his experience and expertise online to give readers trustworthy advice and reviews about Air-conditioning buying, servicing, cleaning and repair in the Philippines.

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