Typically, the cost of a central air conditioner is higher than the average cost to run a window AC unit, which is $0.06 per hour to $0.88 per hour at the national average of $0.13 kWh. That price assumes that the homeowner uses their window unit for eight hours a day.
As it turns out, the most efficient way to keep your home cool and the bills low is to leave the AC running—ideally, with the temperature turned up toward the upper 70s.
By comparison, AC Window Units use approximately 500 to 1,500 watts of electricity. Keep in mind that it takes more than one AC window unit to cool a home. You'll need one for each room of the house you want to reduce the temperature. Here's an ice cube for your glass!
In general, wall and window air conditioning units with smaller capacities can typically run for up to eight hours at a time before they need to rest. Larger wall and window units have a longer running time of around 10 to 12 hours, depending on their cooling power.
Although many people believe that it is more costly to turn your AC on and off vs. leaving it on, this is entirely false. People often base this belief on the idea that powering on your system requires a burst of energy, so leaving it running would minimize energy usage by reducing these bursts.
Running your air conditioner at night will save more money than running it all day. You can set your thermometer to a lower temperature when the sun goes down. As the sun rises, your home will stay more comfortable for longer without running excessively.
According to the Department of Energy1, 78° Fahrenheit is the sweet spot for air conditioners to balance energy savings and comfort when people are at home and need cooling. But in reality, this is a question that doesn't have a “one size fits all” answer.
Best AC Temperature Settings While You Are Home
As you consider the most comfortable room temperature for your lifestyle and family, keep in mind that for each degree that you set your thermostat above 72 degrees, you can save up to 3% on your energy bill.
Wall and window air conditioning units catering to a smaller room can run for about eight to 10 hours before needing rest or a cool-off period. Larger wall units can run up to 12 hours depending on their capacity and cooling power.
During the hot summer months, one effective way to increase the energy efficiency of your window air conditioner is by utilizing curtains or blinds to block sunlight. This simple yet effective method can help keep your room cool and reduce the strain on your AC unit.
Window AC Units Aren't Energy Efficient
Compared to newer central air systems or ductless mini split options, many window AC units are not energy efficient. Some of the newer window units can be a bit more efficient than older models, but on the whole, these systems aren't very efficient.
The average cost per hour to run a window air conditioner is around $0.15. So, if you're running your AC 24 hours a day, you can expect to see a cost of about $3.60 per day on your electricity bill.
Consequences of Running Your Air Conditioner 24 Hours a Day
So the longer your AC operates, the more energy it guzzles, leading to sky-high utility bills at the end of the month. Wasted energy: Running the AC to cool your home beyond your comfort level wastes energy and contributes to an increased carbon footprint.
Cooling yourself with a fan vs. an air conditioner is significantly more energy efficient and cheaper. Fans use around 1% of the electricity consumed by air conditioners. You could leave a fan running for 24 hours and still use less energy than 15 minutes of air conditioning.
Here's the thing: It's normal for your AC to run continuously during hot summer months. You see, on extremely hot days—we're talkin' high 90s to 100s—your system needs to keep up with the incoming heat. To do that, it will run longer in order to maintain a constant, desired temperature in your home.
The short answer is yes, it's more cost-effective to keep your air conditioner on all day. However, don't take this as a green light to crank it up to the max 24/7! There's a smart way to go about it, which we'll delve into in a moment. So, why is it cheaper to leave your AC on?
Running the AC at regular intervals, on the other hand, can save energy and lower utility bills. Using a thermostat in your home that can be programmed to turn off the air conditioner when the space is empty or at cooler times of day can be both cost-effective and advantageous to the environment.
When possible, set your thermostat to at least 78º F in the summer to reduce the difference between outdoor and indoor temperatures as much as possible. You can save six to eight percent on your electric bill for every degree your thermostat is raised above 78º F in the summer, according to Smart Energy.
leaving it on all day and night is better for the HVAC system because it's less taxing. Should you turn off your AC when on vacation? HVAC experts agree it's better to keep your AC on when you're on vacation, especially if you don't plan to leave any windows open.
This is more of a personal question, as different people feel comfortable at different temperatures. Since 72 degrees is generally agreed upon to be an ideal indoor temperature, most people would probably still feel comfortable setting their AC units slightly higher than this, perhaps at around 75.
AC definitely consumes more power than a Fan or a cooler, and how many hours will run AC depends on that your electricity bill will shoot up.
What is the Best Thermostat Setting for Summer Air Conditioner Use? Energy Star recommends the following thermostat temperatures for your air conditioner in the summer: 78°F during the day if people are home. 82°F at night if people are home.
Sleeping in a room with the air conditioner set to an appropriate temperature is important for quality sleep. The ideal AC temperature for sleeping is around 65°F (18.3°C). However, this may differ between individuals, who might find their ideal AC temperature lies between 60 and 67°F (15.6 and 19.4°C).