how much electricity does a mini split use

How Much Electricity Does a Mini Split Use?

Ian Mutuli
Updated on
Ian Mutuli

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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Heating and cooling homes involve various types of HVAC equipment, including ductless mini split air conditioners, which are increasingly common among homeowners thanks to their flexibility and energy efficiency. Even though the electricity consumption of air conditioners is known to be relatively high, mini splits are touted to consume less electricity than central air conditioners. So how much electricity does a mini split use?

Mini-splits work similarly to central air conditioning units. They use an outdoor condenser connected to an indoor unit through refrigerant lines. The outside unit pumps refrigerant into the interior, running through the condenser coils and cooling the air. Although mini split air conditioners are energy efficient, this operation still requires significant energy to run.

In this article, we’ll discuss the electricity consumption of mini splits, the factors affecting their electricity consumption, and how to minimize their electricity consumption.

How Much Electricity Does a Mini-Split Use?

Ductless mini-split

Image Source: grainger.com

The total amount of electricity a mini-split system consumes will depend on its energy-efficiency ratings and cooling capacity. Many models offer around a 9,000 BTU (British Thermal Unit) cooling capacity, using average 500 to 700 watts of electricity. A 12,000 BTU AC electricity usage can be approximately 1,000 watts, while a 48,000 BTU unit can consume up to 5,500 watts per hour. During high heat or extremely cold weather periods, a mini split’s energy use can be much higher than the approximated values.

Mini Split Electricity Consumption Calculation

If you have access to the specification data sheet for your mini-split system, you can find its power consumption. First, you need to determine how many watts your mini split uses.

Mini-split wattage depends on two factors:

  • Cooling or Heating Capacity (denoted BTU or tons). Typically bigger mini-splits will use more watts.
  • Cooling or Heating Efficiency (determined by SEER and HSPF rating, respectively). Mini-splits with higher SEER ratings use fewer watts when cooling, and mini-splits with higher HSPF ratings will use fewer watts when heating.

You can use these factors to calculate how many watts your mini split uses using this formula

Average Cooling Watt Usage = Mini-Split Capacity (BTU) ÷ SEER Rating

For instance, a 9000 BTU 18 SEER mini split will use;

9000 BTU ÷ 18 SEER = 500 watts

This formula also applies to heating watt usage.

Average Heating Watt Usage = Mini split capacity (BTU) ÷ HSPF rating

Therefore a 9000 BTU 10 HSPF split will use;

9000 BTU ÷ 10 HSPF = 900 watts

The amount of electricity used is measured in kilowatt-hours (kWh)

Mini split electricity usage = (Watts x Hours) ÷ 1000

Therefore, a 9,000 BTU 18 SEER mini split will use:

500W x 1 Hour =500 ÷ 1000 = 0.5 kWh per hour

Suppose you run your mini-split for 24 hours per day. In that case, your 9000 BTU will use:

0.5 kWh x 24 Hours = 12 kWh per day

And your monthly mini-split energy consumption will be

12 kWh x 30 days = 360 kWh

How Much Does it Cost to Run a Mini Split Air Conditioner?

Mini-split electricity cost

Image Source: energyvanguard.com

Knowing how much it will cost you to run your mini-split heat pump depends on how much energy your mini-split uses and your local electricity rate. Taking an average electricity price of $0.15 per kWh, running a 9000 BTU mini split for 8 hours per day will cost:

Mini split running cost = Energy usage in kWh x Price of electricity

Running 9000 BTU 18 SEER per day will be;

12 kWh x $0.15 = $1.80 per day

Therefore the monthly cost will be the cost per day multiplied by 30 days

$1.80 x 30 days = $54 Or 360 kWh x $0.15 = $54

Factors Affecting Mini Split’s Electricity Consumption

Mini-split's energy consumption

Image Source: attainablehome.com

1. Difference between the Outdoor Temperature and Set Temperature

The higher the difference between the outdoor temperature and the mini split’s temperature, the harder the air conditioner must work to maintain a comfortable indoor temperature hence consuming more energy.

2. Size of Your Home

The larger the space that needs to be heated or cooled, the more electricity is required.

3. Quality of Home Insulation

Better insulation results in lower energy losses hence less electricity required to maintain the indoor temperature.

4. Efficiency of Your Unit

Mini split systems with higher efficiency ratings require less energy to provide the same amount of cooling or heating or cooling.

5. BTU (British Thermal Unit) Rating of the Air Conditioner

This is the unit’s size or its heating or cooling capacity. The higher the BTU rating, the higher the capacity to heat or cool; generally, this results in more energy consumption.

6. Frequency and Duration of Usage

Frequency of use is one of the significant factors impacting the energy consumption of almost all electric appliances. If you run your mini-split unit throughout the day, it will consume more power. But some new models have timers to automatically adjust temperatures to a more energy-efficient setting or turn the unit off.

7. Condition of the Unit

Older mini-split models are less efficient than newer models. An older mini-split air conditioner may begin to consume more energy as its parts degrade and wear down. Moreover, units that are not adequately maintained normally use more electricity than those kept in good condition.

How to Minimize Mini Split’s Electricity Consumption

Mini-split

Image Source: greenbuildingadvisor.com

1. Use the Appropriate Size Mini Split Unit

As with any HVAC system, proper sizing is imperative. A mini-split system that’s too small will cause the system to overwork. This may not only negatively affect the system’s life, but also, it may not be able to produce enough cool or warm air. Conversely, an oversized system won’t run efficiently, will cause short cycling, poor humidity control, and will consume more energy, resulting in higher bills.

Proper sizing involves considering the size of the room you want to heat or cool, the level of home insulation, layout, and design, and the number of people in the room, among other factors.

2. Maintain Mini Splits Regularly

Regular maintenance is key to mini-split efficiency. A well-maintained mini-split unit will run efficiently, reducing energy wastage. Here is a simple checklist for mini-split maintenance

  • Clean or replace the mini split air filter about every 4-6 weeks. When the air filter is dirty, the unit will work harder to suction in the air, leading to more energy usage.  
  • Clean the unit’s condenser coil about every 4-6 weeks. Ensure to turn off the power and let the system cool for at least an hour. The condenser coil is located in the mini-split outdoor unit.
  • Keep the area surrounding the mini split unit clean. Ensure there’s nothing close to the outdoor or indoor mini-split unit that can potentially block airflow.
  • Ensure proper drainage. The mini split’s evaporator collects condensation through the suction tubing. Ensure the outdoor unit is draining properly.
  • Have an HVAC professional service your equipment at least every two years. 

3. Select an Energy-Efficient Model

If you are determined to keep energy consumption at a minimum, you should consider investing in an energy-efficient mini-split unit. There are two efficiency ratings for air conditioners, including mini splits.

a) Heating Season Performance Factor (HSPF)

The heating efficiency of a mini split heat pump is described by the HSPF (Heating Season Performance Factor). HSPF measures the total heat provided by the unit (in BTU) divided by the total electricity used by the unit (in watt-hours).

An HSPF factor of 8.5 is considered efficient and is the requirement for a unit to qualify for an Energy Star qualification.

b) Seasonal Energy Efficiency Ratio (SEER)

Seasonal Energy Efficiency Ratio (SEER) is an efficiency rating for air conditioners and mini splits operation in the cooling mode. SEER is the total heat removed from the space (expressed in BTU) divided by the total electricity used by the unit (measured in kWh). A SEER rating of above 15 is considered efficient and a requirement for an Energy Star certification.

Mini split air conditioners that are Energy Star-certified are likely to use less electricity than non-certified models. Also, older models may have efficiency ratings between 7 and 10, while newer models have efficiency ratings up to 50. So be sure to look for Energy Star qualification and higher efficiency ratings when browsing mini-split systems. 

4. Use Energy-Efficient Home Upgrades

The condition of your home significantly impacts the energy efficiency of any HVAC equipment, including mini split heat pumps. Properly insulate your home and install energy-efficient windows and doors to ensure warm or cool air doesn’t escape. Also, ensure that there are no interior or exterior wall openings.

Frequently Asked Questions on Mini Split’s Electricity Consumption

Mini-split

Image Source: greenbuildingadvisor.com

1. How much electricity does a mini split use per day?

Averagely, a 9,000 BTU system has an energy consumption ranging from slightly below 4 kWh to less than 15 kWh per day. Other mini-split units in the 24,000 to 36,000 BTU range use about 40 kWh to 90 kWh per day.

2. Should I turn my mini-split off at night?

Unlike traditional, ducted systems, you should always keep your mini split system on to optimize its lifespan and energy efficiency. Turning it on and off causes short cycling that can be costly due to the long start-up times of these systems leading to more energy consumption than letting them run.

3. Do ductless mini-split systems use a lot of electricity?

Mini-splits are an energy-efficient and cost-effective way to heat or cool your home. These units transfer rather than generate heat, and they allow you to select the specific rooms you want to heat or cool. This means that instead of turning on the central air conditioners which adjust the entire house’s temperature, you can only heat or cool the rooms you use.

Final Take

A mini-split heating and cooling system could be an efficient alternative to central air conditioning and heating systems. The average mini-split system consumes a fraction of larger AC systems’ electricity. This is one of the reasons why you should consider having mini-split air conditioners. You can get an approximate estimate using the technical information on the specification sheet for your mini-split heat pump.

Still, how much electricity a mini-split system uses depends on several factors, including the model of the system, frequency of use, the set temperature, and its condition. Choosing an energy-efficient unit is an excellent way to keep electricity usage low. Also, keeping your mini-split filter clean is a great way of reducing energy consumption.

Ian Mutuli

About the author

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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