Can Portable Generator Run Central Air Conditioner? (Yes!)

In this blog post, we will explore the possibility of using portable generators to power central air conditioning systems. As we all know, staying cool during power outages is essential, especially in warmer climates.

We will discuss the factors to consider before connecting a portable generator to a central air conditioner, the steps to do so, and the pros and cons of this method.

Can You Run Your Central Air With The Portable Generator? 

Yes, you can run your central air with a portable generator. But you need at least 10% more generator wattage than your central air wattage. You will get different sizes of portable generators like up to 15KW portable generators in the market. You can run almost all types of central AC with a portable generator.  

Let me be clear, please. Say you have a central air conditioner that comes with 6000 watts starting watt. So, you need a portable generator that comes with at least 6500 watts. Yes, your central air will not consume all the power while running. You can run your other appliances then.

Factors to Consider Before Connecting a Portable Generator to a Central Air Conditioner

A. Power requirements of central air conditioning systems

  • British Thermal Units (BTUs): BTUs measure the cooling capacity of an air conditioner. A higher BTU rating means more cooling power.
  • Tonnage: Tonnage represents the air conditioner’s ability to cool. One ton equals 12,000 BTUs.
  • Energy Efficiency Ratio (EER) and Seasonal Energy Efficiency Ratio (SEER): These ratios measure the efficiency of an air conditioner. Higher numbers indicate better efficiency.

B. Capacity of the portable generator

  • Generator wattage: Generators are rated in watts. Choose a generator with enough wattage to power your air conditioner.
  • Running watts vs. starting watts: Running watts is the continuous power a generator can produce while starting watts are the extra power needed to start an appliance. Make sure your generator can handle both.

C. Compatibility between the generator and air conditioner

  • Types of generators: Inverter generators provide clean, stable power, while conventional generators may produce fluctuations. Central air conditioners require stable power.
  • Clean power output: Ensure your generator has a low total harmonic distortion (THD) to avoid damaging your air conditioner.

D. Safety precautions and proper connections

  • Grounding: Proper grounding is essential to prevent electrical accidents.
  • Transfer switch: A transfer switch safely connects your generator to your home’s electrical system and avoids back-feeding.
Can A Portable Generator Run Central Air Conditioner

How Many Watts Does A Central Air Conditioner Use?

A central air conditioner uses at least 2000-watt power. The range of the central AC is usually 2000 watts to 10000 watts. To run a central air conditioner, you should have a clear idea of the starting and running wattage of your central air.

Actually, it is tough to answer this question accurately. Every appliance comes with a user manual. You will find the starting watt and running watt of your central air conditioner in the manual. Before buying a generator, don’t forget to calculate the overall watts of all home appliances. 

Here is a general power estimation for different types of AC 

Central Air Conditioner3500 Watts
Central AC (with Compressor Off & Fan-Only)750 Watts
Smallest Window AC Units500 Watts
Medium Window AC Units900 Watts
High Window AC Units1440 Watts

Related: Best Generator for Air Conditioners

How Big Of a Generator To Run Central Air?

As I mentioned earlier, you should have a portable generator with at least 1o% more power supply than your central air. If you want to use your portable generator to run heavy appliances in your house, you should go for the high-voltage portable generator. 

Because, you may need to run your furnace, well pump, washing machine, or something like heavy home appliances during the power outage. So, it is good to go for a powerful portable generator. Read this article to understand the sizing of the generator to run the air conditioner.

Run Your Central Air With The Portable Generator

Steps to Connect a Portable Generator to a Central Air Conditioner

  • Determine the power requirements of your central air conditioning system: Check the BTUs, tonnage, and efficiency ratings to understand your air conditioner’s power needs.
  • Select a suitable portable generator: Choose a generator with enough wattage, clean power output, and compatibility with your air conditioner.
  • Ensure proper installation of a transfer switch: Hire a professional electrician to install the transfer switch safely.
  • Connect the generator to the transfer switch: Follow the manufacturer’s instructions and safety guidelines while connecting your generator.
  • Follow safety guidelines while operating the generator: Operate the generator outdoors, away from windows, and keep it well-ventilated to avoid carbon monoxide poisoning.

Pros and Cons of Using a Portable Generator for Central Air Conditioning


  • Temporary cooling solution during power outages: Portable generators can keep your home cool when the power goes out.
  • Portable and versatile energy source: You can use a portable generator for other purposes, such as outdoor activities or emergencies.
  • Cost-effective option compared to standby generators: Portable generators are generally less expensive than permanent standby generators.


  • Limited runtime: Portable generators have a limited runtime, depending on fuel capacity.
  • Maintenance and fuel requirements: Regular maintenance and fuel refills are necessary to keep the generator running.
  • Noise levels: Portable generators can be noisy, which may disturb your peace.


Can A Portable Generator Run A Window AC unit?

Yes, even you could run the Window Ac unit with a 2000-watt portable generator. they need 500 to 3000 running watts. Even, you can run the smallest window AC with the small inverter generator. 

Window AC units are smaller than the central air conditioner. Since you could run the central AC with the portable generator, you could run them smoothly. 

The equation is the same. You must ensure the running watt and starting watt of your window ac. Then select the right [portable generator. 

If you have a comparatively larger generator to run the refrigerator or central AC, you could run all the window AC with the portable generator. 

Will a 9000 or 9500-watt generator run central air?

A 9,500-watt generator may be able to run a central air conditioner, but it depends on the specific power requirements of your air conditioning system. To determine if your generator can handle the load, you need to consider the running and starting watts of your central air conditioner.

Central air conditioners vary in size and power requirements, typically ranging from 1.5 to 5 tons. The power requirement is often measured in British Thermal Units (BTUs) or watts. You can find this information on the air conditioner’s label or in the owner’s manual.

To calculate the required wattage, use the following formula:

Watts = (BTUs per hour) ÷ EER or SEER

Where EER (Energy Efficiency Ratio) or SEER (Seasonal Energy Efficiency Ratio) is the efficiency rating of your air conditioner.

Keep in mind that air conditioners have both running and starting watts. Starting watts are higher than running watts because the compressor requires more power to start. Make sure your 9,500-watt generator can handle both the running and starting watts of your air conditioner.

If your central air conditioner’s power requirements fall within the capacity of a 9,500-watt generator, then it should be able to run the air conditioner. However, it’s important to remember that running other appliances simultaneously will also consume generator power. Always calculate the total power requirements for all devices you plan to run with the generator to avoid overloading it.

Will 6500 Watt Generator Run Central Air?

Yes, you could run the central air conditioner which comes with less than 6500 starting watts with the 6500-watt generator. Usually, you could run the central air along with the other small appliances of your home with a 6500-watt generator. 

Yes, like always you should check the starting watt of your central air. Otherwise, you will regret it. 

Will A 10,000 or 12000 Watt Generator Run Central Air?

you can not only run the central air but also run almost all your home appliances like refrigerator, heater, and others with a 10000-watt generator. a 10000-watt generator is too powerful to run all the appliances smoothly. Yes, I am telling the portable 10000-watt generator. 

Will a 7000 or 8000-watt generator run central air?

Yes, an 8,000-watt generator can generally run a central air conditioner, suitable for systems up to 3.5 or 4 tons. It’s essential to check your air conditioning system’s specific power requirements and consider the power needs of any additional appliances you plan to operate with the generator to avoid overloading.

What size generator is to run a 3-ton ac unit?

To determine the appropriate generator size for a 3-ton AC unit, you need to consider the unit’s power requirements, which are typically measured in BTUs or watts, and the efficiency rating (EER or SEER).

First, find the BTUs per hour for your 3-ton unit. One ton is equal to 12,000 BTUs. Therefore, a 3-ton unit will have 36,000 BTUs.

Next, find the unit’s EER or SEER rating, which is usually listed in the owner’s manual or on the air conditioner’s label.

Now, use the following formula to calculate the running watts:

Running Watts = (BTUs per hour) ÷ EER or SEER

Additionally, consider the starting watts, which are higher than running watts due to the compressor requiring more power to start. Starting watts can be 1.5 to 3 times the running watts.

Once you have calculated the running and starting watts, choose a generator that can handle both. A generator with a capacity of around 7,000 to 8,000 watts should be sufficient to power a 3-ton AC unit, considering some extra capacity for other appliances. However, always verify the specific power requirements of your unit to ensure the selected generator can handle its load.

Can a whole house generator run an air conditioner?

Yes, a whole-house generator can run an air conditioner, as these generators are specifically designed to handle the electrical load of an entire home, including central air conditioning systems. Whole house generators have a higher capacity than portable generators, usually ranging from 12,000 to 25,000 watts or more.

To ensure the generator can handle your air conditioner’s power requirements, check the unit’s running and starting watts, and add the wattage requirements of other essential household appliances. A properly sized whole-house generator should be able to handle the total power demand, allowing you to run your air conditioner and other appliances simultaneously without overloading the generator.

Final Thoughts 

These days portable generators are very powerful indeed. Even you can run your whole house with a portable generator. I hope you have understood everything about your portable generator and central air conditioner. 


Rayan is an engineer, lives in a farmhouse. He has a passion for electronics and alternative energy. He loves to share his thoughts with other people. That is why he started the blog.

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