Choosing an Inverter For Your Air Conditioner

Selecting the right inverter for powering your air conditioner is a crucial step in ensuring optimal performance and efficiency. In this comprehensive guide, we will explore key factors to consider when sizing an inverter, including continuous power rating, surge power rating, waveform, input voltage, and output voltage.

Understanding Inverter Specifications

1. Continuous Power Rating (Watts)

The continuous power rating of an inverter, denoted in watts (W) or kilowatts (kW), represents the maximum power the inverter can consistently supply. The formula for converting Volt-Amperes (VA) to Watts is:

Continuous Power(W)=Continuous Power(VA)×0.8

Table 1: Continuous Power Rating Calculation

InverterContinuous Power (VA)Continuous Power (W)
Inverter A3000 VA2400 W
Inverter B2000 VA1600 W

2. Surge (Peak) Power Rating

Appliances with motors, like air conditioners, require a surge of power when starting up. Surge power rating is typically 2 to 3 times the continuous power rating. The formula for surge power is:

Surge Power(W)=Continuous Power(W)×Surge Factor

Table 2: Surge Power Rating Calculation

InverterContinuous Power (W)Surge FactorSurge Power (W)
Inverter A2400 W2.56000 W
Inverter B1600 W3.04800 W

3. Power Rating Calculation using BTU and EER

For air conditioners, power rating can be calculated using BTU (British Thermal Units) and EER (Energy Efficiency Ratio):

Power Rating (W)=BTU rating ​/ EER

Table 3: Air Conditioner Power Rating Calculation

AC UnitBTU RatingEERPower Rating (W)
AC Unit 15100 BTU11.2455.35 W
AC Unit 28000 BTU12.0666.67 W

4. Potential Starting Wattage Calculation

Starting wattage is crucial for appliances with motors. The formula is:

Potential Starting Wattage(W)=Voltage(V) × LRA(A)

Table 4: Potential Starting Wattage Calculation

AC UnitVoltage (V)LRA (A)Potential Starting Wattage (W)
AC Unit 12407718,480 W
AC Unit 22086012,480 W

5. Rule of Thumb Starting Wattage Calculation

An alternative method is using a starting factor:

Potential Starting Wattage(W)=Running Power(W)×Starting Factor

Table 5: Rule of Thumb Starting Wattage Calculation

AC UnitRunning Power (W)Starting FactorPotential Starting Wattage (W)
AC Unit 1455.3562732.1 W
AC Unit 2666.6764000.02 W


Sizing the right inverter for your air conditioner involves considering continuous and surge power ratings, waveform, input and output voltage, and specific power requirements of your AC unit. By using these formulas and tables, you can confidently choose an inverter that meets the demands of your air conditioning system, ensuring optimal performance and comfort in your living space.

It is also important to note that the inverter should be able to handle the starting current of the air conditioner, which is usually higher than the running current. Therefore, it is recommended to choose an inverter with a capacity that is higher than the power requirement of your air conditioner

It is also recommended to use a load calculator to determine the exact power consumption of your air conditioner 1. Once you have determined the power consumption of your air conditioner, you can use the formula Power (in Watts) = Voltage (in Volts) x Current (in Amperes) to calculate the power requirement of your air conditioner.


The information provided in this article is intended for general informational purposes only and should not be considered as professional advice. Sizing an inverter for your air conditioner involves various technical aspects, and individual requirements may vary.

It is strongly recommended to seek the expertise of a qualified professional or an electrician to assess your specific needs and circumstances. Professional guidance ensures that the selected inverter not only meets the technical specifications outlined in this article but also complies with safety standards and local regulations.

Attempting to size an inverter without professional consultation may lead to incorrect choices, potential safety hazards, and suboptimal performance of your air conditioning system. Always prioritize safety and accuracy by consulting with a professional who can provide personalized recommendations based on your unique situation.


Editor at, specializing in Mechanical Engineering. His enthusiasm for dissecting machines and consumer electronics is a hobby that runs parallel to his love for gaming. Armed with expertise, he effortlessly guides readers through the maze of audio, home appliances, and daily use products, ensuring a seamless and stress-free shopping experience.

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