Compared to other types of air conditioners, such as window AC units and ducted air conditioners, mini-splits are pretty energy-efficient, in the sense that they use less power (kW) and consume less energy (kWh) to perform the same amount of heat exchange.
Even so, mini-splits are still air conditioners, and the electricity consumption of air conditioners is known to be relatively high. So, the question remains, how much electricity does a mini split use? and how much does it cost to run a mini split?
Well, in this article, I’ll discuss the energy consumption (kWh) of mini split air conditioners and how much it actually costs to run these units.
And in case you’re planning on running your mini split on anything other than grid power, you’ll also want to learn about the power usage (wattage) of these units, which I’ll also discuss in this article.
Let’s dive in.
How much energy (kWh) does a mini split use?
Generally, and like any type of air conditioner, the energy consumption (kWh) of a mini-split air conditioner depends on factors such as:
- The BTU (British Thermal Unit) rating of the air conditioner: This rating indicates the size or the heat-exchange capacity of the unit. The higher the BTU rating of the unit, the higher its capacity to exchange heat, and generally, the more energy it will consume.
- The difference between the outdoor temperature and the set temperature: The higher the outdoor temperature, the more energy the air conditioner has to consume to achieve and maintain the set indoor temperature.
- The amount of space that the unit has to cover: The greater the area the unit needs to cover, the more energy it will need to consume.
- The quality of insulation: The better the insulation, the less energy is required to achieve and maintain the set indoor temperature.
- The frequency and duration of usage: The more an air conditioner is used and the longer it runs, the more electricity it will consume.
- The efficiency of the model: Older models are generally less efficient than newer models.
For example, while a 9000 BTU mini-split air conditioner can use as little as 0.3 kWh (kiloWatt-hours) of energy for every hour of runtime with moderate outdoor temperatures (around 85°F), a 24000 BTU mini split unit can use as much as 2 kWh of energy per hour with extreme outdoor temperatures (100°F or more).
Due to these variables, it can be difficult to provide a general estimate of a mini-split’s energy consumption. However, using some rules of thumb, it is still possible to estimate the hourly energy consumption of a mini split air conditioner based on its BTU (British Thermal Unit) rating alone.
The BTU rating of your unit is usually specified by the manufacturer in the model number of the unit or in the EnergyGuide label that comes with the unit.
But to make it even easier for you, I’ve done some research/testing and was able to gather some rough estimates of the hourly energy consumption of mini-split air conditioners based on their Capacity (BTU rating), but also based on the outdoor temperature.
Assuming the indoor set temperature is around 70°F and that the air conditioners are properly sized, the following table provides some rough estimates of the hourly energy consumption of mini-split AC units with different sizes (BTU ratings), and at different outdoor temperatures:
|Outdoor Temperature||BTU Rating||Estimated Hourly Energy Consumption (kWh/hour)|
|12000 (1 ton)||0.4 kWh/hour|
|18000 (1.5 tons)||0.6 kWh/hour|
|24000 (2 tons)||0.75 kWh/hour|
|36000 (3 tons)||1.2 kWh/hour|
|48000 (4 tons)||1.5 kWh/hour|
|60000 (5 tons)||2 kWh/hour|
|12000 (1 ton)||0.6 kWh/hour|
|18000 (1.5 tons)||1 kWh/hour|
|24000 (2 tons)||1.5 kWh/hour|
|36000 (3 tons)||2 kWh/hour|
|48000 (4 tons)||2.5 kWh/hour|
|60000 (5 tons)||3 kWh/hour|
|100°F or more||9000||0.6 kWh+/hour|
|12000 (1 ton)||0.85 kWh+/hour|
|18000 (1.5 tons)||1.25 kWh+/hour|
|24000 (2 tons)||1.7 kWh+/hour|
|36000 (3 tons)||2.5 kWh/hour|
|48000 (4 tons)||3.5 kWh/hour|
|60000 (5 tons)||4.2 kWh/hour|
The estimates provided in the table can help you estimate the daily energy consumption of your unit under similar conditions.
For example, let’s say you’re trying to estimate the daily energy consumption (kWh/day) of your mini split air conditioner, and let’s make the following assumptions:
- Your mini split air conditioner is rated at 12000 BTUs
- You run your unit for 6 hours a day
- The outdoor temperature you’re dealing with is around 95°F
According to the estimates provided in the table above, a 12000 BTU mini split air conditioner will – on average – use about 0.6 kWh/hour (0.6 kiloWatt-hours of energy per hour) in these conditions.
Using this estimate, and the assumption that the AC unit runs for 6 hours a day, you would be able to calculate the daily energy consumption of the unit as such:
Daily Energy Consumption (kWh/day) = Hourly Energy Consumption (kWh/hour) x Daily Usage Duration (hours/day)
Daily Energy Consumption (kWh/day) = 0.6 kWh/hour x 6 hours/day
Daily Energy Consumption (kWh/day) = 3.6 kWh/day
You could then estimate the monthly energy consumption of your mini split unit as such:
Monthly Energy Consumption (kWh/month) = Daily Energy Consumption (kWh/day) x 30
Monthly Energy Consumption (kWh/month) = 3.6 kWh/day x 30
Monthly Energy Consumption (kWh/month) = 108 kWh/month
However, please note that although they should give you an idea about the energy consumption of these mini split air conditioners, the values provided in the table are still estimates. A much better way to determine the energy consumption of your mini split AC unit would be to actually measure it.
How to measure an air conditioner’s energy consumption accurately?
The best way to accurately determine the energy consumption of your AC is to measure it, which can be done using an electricity monitoring device.
Devices such as the Kill-A-Watt meter, allow you to monitor the power usage and the energy consumption of an appliance over a certain period.
For example, to measure the energy consumption of your mini split AC unit over a certain period of time using the Kill-A-Watt meter, all you have to do is plug the monitoring device into the wall outlet and plug your unit into the device and leave the unit running.
You could then push the purple button that says “kWh” to determine the energy consumption of the unit over that period of time:
The following video explains what this metering device is and how you can use it:
Now that we’ve discussed the energy consumption of mini split air conditioners, and how to estimate or even measure it, let’s also talk about how much it actually costs to run a mini split.
How much does it cost to run a mini split air conditioner?
According to the February 2023 data from the EIA (U.S. Energy Information Administration), the (National) average cost per kWh in the U.S. is 15.96 Cents ($0.1596). So, for example, if your mini split air conditioner consumes 150 kWh of energy per month, it would – on average – cost around $24 per month to run the AC unit.
To provide some perspective, the following table estimates how much it would cost per hour, and per month, to run mini split air conditioners of different sizes:
|BTU Rating||Estimated Hourly Cost (Cents/hour)||Estimated Monthly Cost ($/month) (8 hours/day)|
|9000||8 cents/hour||19 $/month|
|12000 (1 ton)||10 cents/hour||23 $/month|
|15000||13 cents/hour||32 $/month|
|18000 (1.5 tons)||16 cents/hour||38 $/month|
|24000 (2 tons)||24 cents/hour||57 $/month|
|36000 (3 tons)||32 cents/hour||76 $/month|
|48000 (4 tons)||40 cents/hour||95 $/month|
|60000 (5 tons)||50 cents/hour||115 $/month|
Please note that the costs provided in the table were calculated using the U.S. national average cost per kWh in February 2023. Also, the monthly cost estimates provided in the table are based on the assumption that the AC unit is left on for 8 hours a day.
The actual cost to run your mini split AC unit will depend on:
1- The amount of energy that your AC unit uses, in kWh (kiloWatt-hours): Which you can determine using the estimates provided in the first section, or by measuring it using an electricity monitoring device.
2- The cost per kWh in your region: Provided here.
Cost = Energy Consumption of the AC (kWh) x Cost per kWh ($/kWh)
For example, let’s make the following assumptions:
- you’re running a 12000 BTU mini split air conditioner that – on average – uses around 120 kWh of energy each month.
- You live in Nevada, in which, according to the EIA, each kWh of electricity costs 17.04 Cents ($0.1704)
The average monthly cost to run your mini split AC unit would be:
Cost = Energy Consumption of the AC (kWh) x Cost per kWh ($/kWh)
Cost = 120 kWh x $0.1704 /kWh
Cost = $20.4
To make this easier, and to help you estimate the cost as accurately as possible, I’ve put together a calculator that determines the cost of running your mini split air conditioner based on:
- Its capacity (BTU rating)
- Your typical daily usage of the unit (in hours)
- Your area (State) and the cost per kWh there
Now that we’ve discussed the energy consumption (kWh) of mini-split air conditioners, and how much these amounts of energy cost, in the next section, I discuss the Power usage (kW) of these units.
The information provided in the next section will be pretty useful if you’re planning on running your mini split AC unit on alternative energy sources.
Mini split AC Power Usage: How many watts does a mini split use?
Like other types of air conditioners, the power usage of a mini-split air conditioner, or its wattage, will mainly depend on its capacity (BTU rating or tonnage), and its efficiency.
For instance, while a 12000 BTU mini split air conditioner uses between 700 and 1000 Watts of power to achieve the set temperature, a 24000 BTU unit will generally use between 1400 and 2000 Watts.
An important thing to note is that most mini-split air conditioners are equipped with an inverter-driven compressor, which means that they don’t operate at a fixed wattage and their power usage varies depending on the required output.
For example, a 12000 BTU mini split unit might use 800-900 Watts of power in the first few minutes of it turned on, but once the set temperature is achieved, the power usage of the unit decreases to about 200-300 Watts, which is enough to maintain the set temperature.
For comparison, and to provide more perspective, the following table estimates the average amount of power that mini-split AC units of different BTU ratings use to achieve the set temperature and their power usage once the set temperature is reached:
|BTU Rating||Avg. Running Wattage||Wattage at Set Temperature||Avg. Amperage at 115-130 V(AC)|
|9000||700 Watts||100 – 200 Watts||6 Amps|
|12000||900 Watts||200 – 300 Watts||8 Amps|
|15000||1100 Watts||300 – 400 Watts||10 Amps|
|18000||1400 Watts||350 – 500 Watts||12 Amps|
|24000||1800 Watts||550 – 750 Watts||16 Amps|
|36000||2800 Watts||700 – 1000 Watts||24 Amps|
|48000||3500 Watts||1000 – 1400 Watts||32 Amps|
|60000||4500 Watts||1300 – 1700 Watts||40 Amps|
The “Average Running Wattage” estimates provided in the table represent the typical amount of power that these AC units require to reach the set temperature, and the “Wattage at Set temperature” estimates represent the amount of power typically used by these units to maintain the temperature setpoint.
Fabulous article, and the ONLY place on the entire web where I could find good answers to electrical power consumption questions!! MANY THANKS! I am trying to work out how to size a portable electrical generator for backup and needed to know the wattage.
Appreciate your wisdom!
Hey there Bill,
I appreciate it.
I would say a 2000 Watt generator will do the trick for anything less than 18000 BTUs, maybe even up to 24000 BTUs, since mini splits with this kind of capacity will generally use less than 2000 Watts of power and don’t require a huge amount of power when starting up.
Before you make any purchases, please refer to the specification label of your unit, and look for the amperage rating specified (in Amps or “A” for short) by the manufacturer.
Once you find this amperage rating, multiply it by the voltage rating of the unit (around 120 Volts). This will help you determine the power usage of your unit more accurately.
For example, if your unit is rated at 115 Volts and 12 Amps, its rated power usage will be 115 V x 12 A = 1380 Watts. A 2000W generator will do the trick.
Hope this helps.