Too much confusion and too many people ask; does turning on and off the AC cost more money, or does leaving the AC on waste electricity?
And the answer is not straightforward and can be tricky sometimes, as it depends on the place where the AC is being used, the type and size of the AC unit, the behavior of the people occupying the place, the efficiency of the insulation, and some other factors.
I will try to explain here when it is better to turn on and off the AC vs. when it is better to leave it on, so that you can do your best in order to save on the AC bill.
Does Turning The AC On and Off Cost More?
Generally speaking; no. Turning the AC on and off does not cost more money than leaving it on all the time.
There’s a misconception that makes people think that they should not turn on and off the AC frequently, because everytime you turn the AC on, it works at full capacity in order to get the place to the desired temperature degree, and that this operation costs more money than leaving it on all the time.
And while it is true that the air conditioner will work on full capacity in order to get the desired temperature, but the electric energy consumed would be less than the total that will be consumed when it is kept running all the time even when it is not in need.
In general, turning the ac on and off does not waste electricity if you intend on turning it off for many hours before the next operation, especially when the place will not be occupied for several hours.
Does Turning The Air Conditioner On and Off Raise The Bill?
In most cases, no, turning the AC on and off does not raise the bill, but it actually lowers it because the electricity saved by turning off the AC for hours over weighs the energy consumed when once it is turned on.
Is it More Efficient to Leave Air Conditioning On?
In general, it is not more efficient if you leave the AC on all the time, as that means that it will work more hours at low capacity, when means lower efficiency.
Also, if the space where the AC is installed stays unoccupied for several hours, then depending on the insulation, it will continuously lose the desired temperature, and that will require the AC to keep working just to cool down or warm up the place depending on the mode, while nobody is actually there to benefit from that cooling or heating.
Just like it is when you leave the lights on and waste electricity when nobody is in the place to benefit from the light.
Therefore, whenever you leave a place and you intend to stay absent for several hours, it is more efficient and cheaper to turn off the AC.
When Does it Become Better to Leave The AC On?
Sometimes it might not make big difference when we are talking about turning the AC on and off while you are still in the place, but you want to save some energy.
Note that most non-inverter AC units turn off the fan automatically when there thermostat detects that the set temperature is achieved, and turn it on again when the temperature drops by few degrees.
This ensures that the AC will either work at full capacity, which gives the highest efficiency and causes the lowest energy waste, and ends up costing less than working all the time but at a lower than the full capacity.
And the inverter type AC units will change the speed of the fan based on the need in order to maintain the temperature within a small range that is comfortable.
But the problem might arise if the AC unit is oversized for the area, which means that it will not run at full capacity, and that means low efficiency that wastes energy and money.
In that case, it might be worth it to turn it off when you feel comfortable, and switch it on again when you feel uncomfortable with the temperature.
But note that these cases are related to turning on and off the AC when you are still in the place where you need to keep the temperature at a certain level.
Now you might ask, is it better to leave the air conditioner on all night when you are there?
The answer depends on your place’s insulation and its ability to maintain a comfortable temperature.
If the place has good insulation, then you might want to set a timer that turns the AC off at a certain hour.
But if the insulation is not that good, then you might need to leave the AC on all night even though it will consume more electricity, since the intent from installing it in the first place is to feel comfortable.
But there are some tips that can help you reduce the AC bill even when you keep it on all the time, which you will discover in the following section.
Does Leaving The AC Fan On Waste Electricity?
Leaving the AC fan consumes electricity, but it is less than what is consumed if you leave the whole AC unit on.
Sometimes leaving the AC fan or humidifier on can give you the comfort you need at a lower price.
How Much Money Do You Save by Turning Off The AC?
To make a simple calculation, let’s assume that you have a 1-ton split AC unit, which on average consumes around 1.5 kWh per one hour of operation at full capacity.
Let’s assume that you are used to leave it on for an extra four hours a day at full capacity, that means that it consumes around 6 kWh per day during these four hours.
Multiplied by 30 days, that accumulates into 180 kWh per month.
In a place like Texas, where the rate is around 11 cents/kWh, the cost would be $0.11X180= $19.8 per month that you could save if you turned off the AC during these extra hours.
And in a place like New York where the rate is around 19 cents/kWh, that cost would be $.19X180= $34.2 per month that you could save if you switched the AC off.
This is only when talking about one small unit of 1-ton capacity, operated an extra four hours a day.
Note that some places might have more than one AC unit, and many could be bigger than the 1-ton unit we used in the estimate above.
And above all, many people leave the AC on all the time when there leave their home, which is usually more than eight hours a day.
The costs can add up pretty quickly and can add a significant amount to your bill.
Solutions if You Can’t Turn Off The AC
Sometimes it might be difficult for you to turn off the AC, either because you or other people keep forgetting it on, or maybe you need to keep it on in order to combat high humidity that could cause some damages to the place.
Or maybe because it is difficult to maintain the desired temperature in the place for long time.
In these cases, here are some tips that will help you use the air conditioner economically and save some money:
- Use a Smart Programmable Thermostat: Programmable thermostats are becoming popular as they can be set in advance in order to turn on and off the AC automatically based on a certain schedule and temperature degrees that you set, which could be different from one day to another based on the occupancy and behavior in the place.
This can be a real saver that you can rely on in case you forget to turn off AC before leaving.
Also, many of them can be connected to the WIFI network, which allows you to control them through your mobile phone, even when you are on vacation.
That can help you maintain a good temperature and humidity level in case your place is in a cold area with high humidity.
- Fix The Insulation: You can use an infrared thermometer temperature gun in order to inspect the walls and the windows, and see where there’s poor insulation or sealing that causes the temperature to be transferred between the inside and the outside of the place, and fix the insulation there.
- Keep Doors and Windows Closed: Try as much as you can to keep the doors and windows closed and sealed properly in order to prevent the heat exchange between the different rooms, and between the inside and the outside atmosphere.
Otherwise, it would be like trying to fill in a water tank while there’s a hole at the bottom from which water keeps leaking.
- Use Fans & Dehumidifiers: Sometimes you don’t need to keep the AC on in order to feel comfortable, but what you need is either a little air movement, or maybe you need to reduce the humidity level.
In these cases, you can either use a separate fan or dehumidifier, or you can use the fan and dehumidifier modes in the AC unit itself, which consume less electricity that it is with leaving the air conditioner on all the time.
- Raise The Temperature: When used for cooling, every degree you lower your AC setting causes a significant increase in the bill. And the same with every degree you increase the setting when used for heating.
Try to set the AC as high and comfortable as possible during the hot weather, and as low and comfortable as possible during the cold weather, as doing so could help in lowering your bill 10% a year on heating and cooling if you turn the thermostat back 7°-10°F for 8 hours a day from its normal setting. (Source: Energy Department)
- Install an Energy Star Inverter AC: Energy Star appliances are built with the latest energy-saving technologies and recommendations. And inverter AC units are more energy efficient than non-inverter units.
If the air conditioning units at your place are older than 10 years old, then you might consider contacting a professional to inspect them and see if it is worth replacing them with Energy Star inverter AC units that would save you money on the long run.
Conclusion – Turning AC On and Off vs. Leaving it On
Try to turn off the AC whenever you leave the place instead of leaving it on all the time so that you save electricity.
And in the cases where you need to keep it on because you are still at the place, or because you want to avoid high humidity levels, then utilize some of the tips in the previous section, which could help you to efficiently use the AC even when it is kept on.
I hope that you now have a clear answer on your question and understand if you should turn on and off the AC or leave it on all the time.
If you are still confused and have specific questions, please, leave them in the comments’ section below, and I will be happy to help you out.
And if you found this article helpful, then please, feel free to share it with someone who could benefit from reading it 🙂