How Much Does It Cost to Run a Mini Split Per Month

A ductless mini split or a ductless heat pump is a common climate control system in most American households. It is capable of heating and cooling with a comparatively small, energy efficient design.

Although most homeowners are attracted to the comfort and flexibility that a mini split provides, they tend to ask the following question: How much does it cost to run a mini split per month?

This paper will discuss the major determinants of operating costs, methods of estimating monthly cost and energy conservation.

Looking closely at the energy consumption, efficiency ratings, local electricity rates, and some other factors, a homeowner can obtain a better idea of how much he/she may expect to pay. The details are further dissected in the following sections in a manner that is not only comprehensive but also easy to understand.

Understanding Mini Split Systems

Mini split systems are divided into two components namely an outdoor compressor/condenser unit and one or more indoor air-handling units. In contrast to the conventional HVAC systems which use ducts to circulate the conditioned air in a house, a ductless mini split system provides air directly to the specific zone or room.

Key characteristics include:

1. Zoned Temperature Control: The indoor units can be controlled individually. This implies that only the areas that require heating or cooling are heated or cooled thus minimizing on wastage of energy.
2. Easy and Small-Space Installation: Since these systems do not need much ductwork, they are easier to retrofit in an older house or can be installed in a new building.
3. Energy Efficiency: A lot of mini split models possess high Seasonal Energy Efficiency Ratios (SEER) which means that they perform better in cooling with less energy.
4. Dual Heating and Cooling: Certain mini splits are heat pumps, and can provide both heating during the winter and cooling during the summer. It may be a more effective option to individual cooling and heating systems.

Such characteristics can save homeowners a lot of money in comparison to operating a less efficient window air conditioner or an older ducted HVAC system. The monthly cost however depends on various factors which are discussed in the following sections.

Key Factors Affecting Monthly Operating Costs

The price of operating a mini split varies monthly and is determined by a set of factors that can have a great impact on the amount of electricity consumed. These factors are important in better budgeting.

1. System Size and Capacity (BTU)
   • Mini splits are measured in British Thermal Units (BTU) to determine heating and cooling capacity. A larger BTU rating means the unit can handle more space or bigger cooling/heating loads.
   • In case the system is oversized, it may short-cycle (switch on and off more often) and become inefficient. When it is too small, it will be running all the time and this may end up consuming more electricity.
2. Energy Efficiency (SEER and HSPF)
   • SEER (Seasonal Energy Efficiency Ratio) is used for cooling. A higher SEER rating means better cooling efficiency.
   • Heating is done by HSPF (Heating Seasonal Performance Factor). The higher the HSPF rating the more efficient the heating.
   • High SEER or HSPF mini splits are more expensive initially, but they are likely to have lower monthly operating expenses.
3. Local Electricity Rates
   • Electricity rates in the United States vary widely by region. The national average hovers around $0.12 to $0.16 per kWh, but some areas may pay as low as $0.10 or as high as $0.20 or more per kWh.
   • The difference in cost per kWh can have a considerable effect on the monthly bill, even a small one, especially when the usage is high.
4. Frequency and Duration of Use
   • The longer a mini split operates, the more electricity it consumes. Households that run their system 24/7 during summer or winter months will see higher bills than those using it occasionally.
   • The frequency of use can be moderated and hence reduced by the use of zoning capabilities (e.g., turning off the indoor units in rooms that are not in use).
5. Climate and Insulation
   • Homes in very hot or cold climates generally rely on their mini splits more heavily, especially during extreme temperature spikes.
   • The insulation of the walls, roof, and windows of the house will determine the effectiveness of the house to hold the conditioned air, which directly determines the extent to which the mini split will have to work to ensure that the indoor temperature remains constant.
6. Maintenance and Condition
   • A well-maintained mini split will operate at optimal efficiency. Dirty filters, obstructed outdoor units, or leaking refrigerant lines can all force the system to use more electricity.
   • The unit is maintained regularly through cleaning of filters and inspections of coils to make it work efficiently.

Average Monthly Cost Estimates

Although there is no single number that can be given, it is useful to consider common situations.

The next estimates may be used as a general guideline on monthly operating costs in the United States.

1. Small Capacity Units (9,000–12,000 BTU)
   • These units typically serve a single room or small zone (e.g., a bedroom, home office, or living area under 500 square feet).
   • Assuming that electricity is priced at 0.13 dollars per kWh and the unit is used about 8 hours a day in moderate climates, it may be estimated that cooling or heating a small area will cost about 15-30 dollars per month.
2. Mid Capacity Units (18,000–24,000 BTU)
   • These serve mid-sized spaces (often 500–1,000 square feet).
   • In the same scenario, an average of 0.13 dollars per kWh and 8-hour usage cycle, the monthly expenses may amount to 30-50 dollars. This may be much higher in climates that are more extreme or have 24/7 usage patterns.
3. Higher Capacity Units (30,000–36,000+ BTU)
   • Systems this size might handle multiple rooms or an entire open-concept space.
   • The monthly running costs could be between 50-80 dollars with similar assumptions. Once more, the real costs may be more in case the unit operates constantly or in case the local rates are more than 0.16 dollars per kWh.

It is necessary to mention that the particular SEER rating plays a significant role. A unit having a SEER of 20 or more could use about 20 to 30 percent less electricity than a unit with a SEER of 14 when used under comparable conditions.

How to Calculate Your Mini Split’s Monthly Cost

A simple formula can be used by the homeowners who want to have a more realistic view of the monthly expenses. It involves knowing the wattage or power consumption of the mini split, the number of hours it will be in use and the cost of electricity in the area.

1. Find the Power Consumption of the Mini Split
   • The power consumption is often listed in watts (W) or kilowatts (kW). Many manufacturers provide this information on the unit’s specification sheet.
   • In case the information is given in watts, divide by 1,000 to get the value in kW. e.g. 1,000 watts = 1 kW.
2. Estimate Daily Operating Hours
   • Determine how many hours per day the mini split is running. This can be an approximation based on personal usage habits or typical HVAC runtime data.
3. Multiply Power by Time
   • Use the formula: Energy Usage (kWh)=Power (kW)×Operating Hours (h)\text{Energy Usage (kWh)} = \text{Power (kW)} \times \text{Operating Hours (h)}Energy Usage (kWh)=Power (kW)×Operating Hours (h)
   • As an example, when the mini split uses 1.2 kW and works 8 hours a day, it uses 1.2 kW 8 h = 9.6 kWh a day.
4. Multiply by Electricity Rate
   • Multiply daily kWh by the local cost per kWh to find daily cost, then multiply by 30 (or the number of days in the billing cycle) to get the monthly cost.
   • Example: 9.6 kWh/day x 0.13/kWh = 1.25/day. In more than 30 days, 1.25 30 = 37.50/month.
5. Account for Seasonality
   • Summer and winter usage may differ in length and intensity. Adjust daily hours or usage patterns to reflect seasonal demands more accurately.
   • There are homeowners that only use mini splits during one season (cooling only or heating only) and there are those that use it throughout the year.

Real-Life Examples of Cost Scenarios

Looking at hypothetical but realistic cases, homeowners can have a better point of reference on the monthly mini split operating costs.

1. Single-Zone Mini Split in a Mild Climate
   • A homeowner in a region with moderate summers and mild winters might have a single-zone 12,000 BTU system with a SEER 18 rating.
   • Suppose that the average consumption is 0.85 kW per hour of operation, then operating the unit 6 hours a day in the hottest month of the summer may produce approximately 5.1 kWh/day.
   • That is 0.13/kWh, or 0.66 a day, or about 19.80 a month.
2. Multi-Zone Mini Split in a Warmer Climate
   • In a humid Southeastern state, a homeowner might have a 24,000 BTU multi-zone mini split serving two rooms.
   • When the system is operating 10 hours a day in a hot summer, the operating power may be about 1.8 kW. That comes to 18 kWh/day.
   • That is 0.14/kWh, or 2.52 dollars per day or approximately 75.60 dollars per month.
3. Year-Round Use in a Cold-Winter State
   • A household in the Northeast using a mini split as a primary heat source might have a system rated at 24,000 BTU with a high HSPF for cold climates.
   • During a very cold month, the mini split might operate 12 hours or more per day at approximately 2.0 kW, and this would represent approximately 24 kWh/day.
   • The daily cost is 0.15/kWh = 3.60 and monthly cost of 30 days is 108.

Each household can come up with a more customized monthly cost by comparing the actual or estimated usage data and the local electricity rates.

Strategies to Reduce Monthly Costs

To the people who are worried about reducing monthly energy bills, there are some easy measures that can make a mini split run more efficiently:

1. Proper Sizing
   • Having a professional size the mini split system ensures it is neither too large nor too small for the area it serves. This directly impacts how often it runs and how much power it draws.
2. High-Efficiency Models
   • Choosing a higher SEER and HSPF rating might result in a higher upfront investment, but such systems typically recoup costs over time with lower monthly bills.
3. Regular Maintenance
   • Cleaning or replacing air filters monthly (or as recommended) and checking outdoor units for debris help maintain optimal airflow.
   • Annual professional inspection will help to avoid the development of minor problems into efficiency-killing problems.
4. Use Zoning Wisely
   • If the mini split supports multiple zones, shutting off units in unoccupied rooms prevents cooling or heating empty spaces.
   • Setting the temperature of each zone to a slightly higher (in summer) or lower (in winter) temperature can lead to great savings in energy.
5. Improve Insulation
   • Ensuring the home is adequately sealed and insulated keeps conditioned air from escaping, meaning the mini split can cycle less frequently.
   • A cheap method of improving the overall performance of HVAC is sealing of gaps around windows, doors, and attics.
6. Manage Thermostat Settings
   • Using programmable or smart thermostats (if compatible) to set schedules reduces unnecessary usage.
   • Adjusting the thermostat by a few degrees in summer or winter than the normal comfort level can give a visible saving.

Comparing Mini Splits to Other HVAC Options

It is usually beneficial that homeowners compare mini splits with other popular HVAC systems.

1. Window Air Conditioners
   • Window AC units are generally more affordable to purchase initially but often less energy-efficient.
   • They are expensive to provide year round comfort and when a house requires several units to serve different rooms.
2. Central Air Conditioning
   • Central AC systems distribute cooled or heated air through ductwork. If the ducts are not well-sealed or if the central system has a lower SEER rating, energy loss can be significant.
   • Efficiency may be good in well-sealed houses with modern central systems. Nevertheless, the absence of zone control may also imply increased expenses in case a person needs to cool or heat the whole house to ensure that a few rooms are comfortable.
3. Space Heaters
   • Space heaters can be cheap to purchase, but they can lead to notably higher electricity costs if used extensively. They also only heat, making them less versatile than a mini split that can both cool and heat.
4. Traditional Heat Pumps
   • Traditional heat pumps function similarly to mini splits but usually include duct systems. Ductless mini splits may have higher efficiency because they avoid the energy losses associated with ductwork.

Mini splits can be a good compromise between comfort and lower monthly bills, given efficiency ratings, installation costs, and flexibility.

When a Mini Split Might Not Be the Best Fit

Even though a mini split might be useful in most of the homes, there are circumstances in which it might not be the best:

1. Extremely Large Spaces
   • Heating and cooling very large, open areas exclusively with a mini split might require multiple units, which could escalate installation costs.
   • In other instances, a central system or several mini splits in combination might be more suitable.
2. Very Low Electricity Costs Elsewhere
   • In rare scenarios where alternative heating sources (such as natural gas or geothermal) offer significantly cheaper rates, a mini split’s operational costs might be higher.
3. Homeowners Unwilling to Maintain the System
   • Mini splits require regular maintenance, especially filter cleaning. Those who prefer low-maintenance solutions might find central systems with less frequent filter changes more convenient.

However, in the majority of residential applications, particularly where zoned control is required, mini splits excel when it comes to monthly operating expenses and energy efficiency.