What Size Generator To Run A Portable Air Conditioner?

Have you been searching for portable AC and confused about the most compatible generator size to run it? What size generator to run portable AC? You don’t want to spend money buying a generator only to find out that it doesn’t have enough power to run your portable AC.

There is no specific answer to this paradox, as the adequate size depends on different AC power requirements. We’re going to explore different scenarios so that you can choose the best option for your case.

What Size Generator To Run Portable AC? (Explained For Different AC Sizes)

Yes, it is possible to run a portable AC on a generator. According to experts’ advice, here are the most recommended generator sizes required to run different Portable ACs.

Generator Size for Portable AC

8,000 BTU Portable AC Generator Size

A portable AC with an 8,000 BTU cooling capacity requires a generator with at least a 4000-watt output. According to manufacturer requirements, 8,000BTU needs 800 watts when running and 1350 watts when starting.

10,000 BTU Portable AC Generator Size

A portable AC with a 10,000 BTU cooling capacity requires a generator with 4200-watt output. This type of AC needs 1000 watts when running and 1500 watts when starting.

12,000 BTU Portable AC Generator Size

For this type of portable AC, the generator size fit to handle it should have 5000 watts or higher capacity. ACs with this BTU rating usually require 1200 watts running and 2000 watts at startup. This refers to an EER rating of 8 to 12. Experts show this type of BTU AC uses around 900 watts per hour.

14,000 BTU Portable AC Generator Size

A portable AC with a 14,000 BTU cooling capacity requires a generator with a 5500-watt output. This type of AC usually requires around 2200 watts running and 3000 watts starting. Its amperage requirement is 11.9 amps.

Quick Comparison Of Generator Sizes For Portable AC

Portable AC Size BTU8,00010,00012,000
Generator Size needed minimum watt4,0004,2005,000
Amperage required when running (amps)8.39.511.9
Amperage required when starting (amps)121619.5

According to the table above, different generator sizes can run different portable ACs. Therefore, the size of the generator you need will vary accordingly depending on the BTU rating of the AC.

How To Calculate The Size Of Generator For My Portable AC?

Size and Wattage of Portable AC Unit:

To calculate the size of the generator, you need your portable AC unit in wattage. You can find this information in the owner’s manual or the product specifications sheet. Once you have the wattage, match it with the corresponding generator size in the table above.

Size and Wattage of Generator:

To calculate the generator’s wattage, you are required to multiply the size of your AC unit by the wattage. This will give the total wattage your generator needs to run the AC unit.

Equation and Sample Computation:

Equation: The wattage of generator = Size of AC unit (watts) x Number of watts

Sample computation: Size of portable AC unit (in watts): 1,200

Wattage of generator needed (in watts): 1,200 x 1 = 1,200

The size of the generator you need is a 1,200-watt generator.

To know the wattage by HVAC formula, divide the BTU with EER:

According to the HVAC formula guidelines, first, calculate the square footage of the area to be cooled. Then, multiply the square footage obtained for each area by 25. Add 400 for each other person that works in that particular area. Add 1,000 for each window.

Costs Associated With Using A Generator For Cooling

If you are looking forward to using a generator to power your portable AC, you need to calculate the additional costs associated with the process. This includes the cost of the generator itself and the cost of fuel for running the generator. Besides this, you will need to factor in the price of any necessary extension cords or transfer switches.

Additional Costs
  • Cost of generator: This varies depending on the size and type of generator you purchase.
  • Cost of fuel: The fuel cost depends on the type of fuel your generator uses (gasoline, diesel, propane, etc.)
  • Cost of extension cords: If you need to use an extension cord to run your generator, you need to factor in the cost of the cord.
  • Cost of transfer switch: If you do not have an existing transfer switch, you may need to purchase one. This will add to the overall cost of using a generator for cooling.

It is vital to factor in all costs associated with using a generator for cooling before deciding whether to use one. This is to ensure you make an informed decision that is best for your needs.

The cost of running a generator for cooling is significantly more than powering a portable AC unit with electricity from the grid. The average price of a generator is around $500, while the cost of electricity is meager. In addition, generators require regular maintenance and must be fueled to run.

Portable AC units, on the other hand, are affordable and do not require additional expenses and maintenance to run them efficiently. For example, the average price for a 10,000 BTU portable AC unit is around $200.

Cost of Using Generator for Portable AC

People Also Ask (FAQ)

Below are common generator and portable AC questions.

What are some reasons people use generators to power AC units?

A generator can provide backup power in the event of a power outage, and they are more reliable than the grid. So even if there are power outages in your area, you can rest assured knowing that your generator will still be running.

How do you connect a portable AC to a generator?

First, you need an adapter that allows you to plug the AC unit into the generator. You can find these adapters at most hardware stores.

Second, make sure the generator has enough power to run the AC unit. Most generators have a rating system that tells you how much power they can provide.

Finally, confirm the generator is properly grounded.

When using a generator to power an AC unit, it’s important to follow all safety precautions. Make sure the generator is in a well-ventilated area, and never run it inside your home or garage.

Besides, the generator should be properly grounded before plugging anything into it. If you’re not sure how to do this, seek assistance from a professional.

How long and often you can run a portable air conditioner with a generator?

How long and often you can run a portable AC unit with a generator depends on the size of the generator and the AC unit. Most generators have a rating system that indicates how much power they can provide. It’s critical to ensure the generator you’re using has enough power to run the AC unit. If it doesn’t, you may need to upgrade to a generator that can provide more power.

In general, you can run a portable AC unit with a generator for as long as the generator has fuel. However, you’ll need to make sure that the AC unit is properly vented. If it’s not, the generator could overheat.

It’s also important to remember that generators are not meant to be used continuously. Make sure that you give the generator time to rest in between uses.


It’s possible to run a portable AC on a generator. But you have to consider the size of the AC to buy the appropriate generator. Just use the equation mentioned above to quickly reach a conclusion.

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Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.