airconditioner generator

What Generator Size To Run an Air Conditioner? – Choosing the Perfect Fit

During the hot summer months, many people rely on air conditioners to maintain a comfortable temperature. However, what if you’re at a job site with limited power access or in an RV without a connection to the grid?

In these situations, purchasing or renting a generator to power your AC becomes necessary. With a wide variety of generators available, determining the right size can be a challenge. This article will guide you in selecting the appropriate generator size to effectively operate your air conditioner.

Generator Size for Running an Air Conditioner

Typically, a central air conditioner consumes between 3,000 and 3,500 watts per hour, while a window air conditioner uses 500 to 1,500 watts per hour. Keep in mind that some ACs may require 2 to 3 times more wattage for a brief period when starting the compressor.

How to Determine the Right Generator Size for Your Air Conditioner?

Can a honda eu2200i power a 15000 BTU

To figure out the appropriate generator size for your AC, take into account a few factors. Firstly, consider the AC unit’s running wattage. Most units will have a label indicating the wattage requirements; for instance, a standard window air conditioner may need 1,000 watts.

Secondly, take into account the start-up or surge wattage, which is the power required to start the AC unit. This figure is usually significantly higher than the running wattage and can be up to three times greater. You can find the start-up or surge wattage in the owner’s manual or on the AC unit itself.

The generator specifications should list both the running wattage and the start-up or surge wattage.

Tip: If you can’t find your AC’s wattage, look up the model number online to find the specifications or manual, which should provide the necessary information.

Once you know the AC unit’s wattage requirements, you can choose a generator capable of supplying that power. For example, if a standard window air conditioner needs 2,000 watts for starting and 1,000 watts for running, you’ll require a generator that can deliver at least 1,000 watts of continuous power and 2,000 watts of surge wattage to start your AC.

If you can’t find the wattage size, you can use the AC Unit Size, which is measured in Tons and BTUs on your Air Conditioner. To calculate the number of tons, divide the number of BTUs by 12,000.

BTU Ton (size of AC) Approx. Watts Kilowatts (kW)
12,000 1 4,000 4
18,000 1.5 6,000 6
24,000 2 8,000 8
36,000 3 12,000 12
48,000 4 15,000 15
60,000 5 18,000 18

Table to roughly determine the number of Watts depending on AC Unit Size

Top Generators for Running an Air Conditioner

Inverter Generator

Several kinds of generators can power an air conditioner, with gas generators being the most common, followed by diesel and propane generators.

Gas generators are a prevalent option because they are generally more affordable than diesel or propane generators and offer an extended runtime.

Diesel generators are ideal for those requiring a generator capable of handling a heavy load, like powering an air conditioner.

Propane generators are an excellent choice for those seeking a portable generator that is easy to store.

Below is a list of some of the most sought-after generators for running an air conditioner:

DuroMax XP15000E Gas-Powered Portable Generator

DuroMax XP15000E Gas-Powered Portable Generator

The robust DuroMax XP15000E generator is driven by a V-Twin Engine, delivering an impressive 12,000 running watts suitable for heavy-duty power demands. This V-Twin engine generates 23 horsepower, making it ideal for homes and job sites. Its operating volume is 74 dBA, which is standard for most generators.

This device features four outlets: a 120/240V 50A heavy-duty outlet, a 120V 30A twist-lock outlet, a 120V 20A GFCI outlet, and a 120/240V 30A twist-lock outlet. The generator has a large 10.8-gallon fuel tank, providing around nine hours of runtime at 50% load. When fuel is low, the sensor automatically shuts off the device.

Champion Power 3500W Equipment Portable Generator

Champion Power 3500W Equipment Portable Generator

The Champion Power generator has enough capacity to start and operate a 15,000 BTU RV air conditioner. Equipped with a 224cc engine, it produces 3,500 running watts on gasoline, adequate for running an air conditioner. Its 3.4-gallon fuel tank can operate for nine hours at 50% load using gasoline.

With propane, the generator produces 3,150 running watts and can run for 10.5 hours at 50% load using a 20-pound propane tank. The generator’s noise level of 68 dBA is relatively mild. It offers four outlets: two 120V 20A household outlets, one 120V 30A locking outlet, and one 120V 30A RV.

WEN GN6000 6000-Watt Portable Generator

WEN GN6000 6000-Watt Portable Generator

WEN offers an affordable 6,000W generator packed with excellent features and specs. It produces 500 running watts, sufficient for powering an air conditioner. The 3.4-gallon fuel tank can operate for 7.5 hours at 50% load.

The generator is powered by a 272cc, 4-stroke, OHV engine with an average speed of 3,600 RPM. The device features six outlets: one 12-Volt DC outlet, two standard household outlets (5-20R), one 120-Volt/240-Volt L14-30R outlet, one 30 Amp TT-30R RV outlet, and a 120-Volt to 240-Volt voltage selector.

Champion 3,400-Watt Portable Inverter Generator

Champion 3,400-Watt Portable Inverter Generator

The dual-fuel Champion 3,400W generator can operate on either propane or gasoline. It delivers 3,100 running watts, perfect for powering a window air conditioner. Designed specifically for RV use, it includes a dedicated 120V 30 amp RV outlet.

With a noise level of 58 dBA, the generator is relatively quiet. It features four outlets: two 120V 20A outlets, one 120V 30A RV outlet, and one 12V USB port. The generator has a 192cc 4-stroke air-cooled single-cylinder engine and a 1.6-gallon fuel tank. Its runtime is 7.5 hours with gas at 25% load capacity and 14.5 hours with propane at 25% load capacity.

Buffalo Tools GEN1000I 1000 Watt Inverter Generator

Buffalo Tools GEN1000I 1000 Watt Inverter Generator

The smallest generator on our list, the Buffalo Tools GEN1000I, is sufficient for powering a small RV air conditioner. Extremely quiet, it operates at a noise level of 56 decibels and delivers 1,000 watts of power to keep devices running during power outages.

It has a 0.55-gallon fuel tank, which can provide approximately 6 hours of runtime at 50% load. The control panel consists of a 120V DC outlet and a 120V AC outlet. The smart eco-mode enhances fuel efficiency by managing the engine’s RPM.

Can a 7,500-Watt Generator Power My Air Conditioner?

It is crucial to know your air conditioner’s wattage requirements beforehand. Generally, a 7,500-watt generator should be adequate to run a typical air conditioner. However, if you also plan to operate other appliances or electronic devices using the generator, you might need to opt for a larger model.

To ensure you choose the appropriate generator for your needs, it is recommended to consult an expert.

Which Generator Can Run an AC?

Honda EU2200

Several types of generators can power an AC. The most common type is a gasoline generator, which is typically used for emergencies due to its portability and ease of use. However, they can be noisy and emit harmful fumes. Another option is a propane generator, which is also portable and easy to use, but with the advantage of being quieter and fume-free.

Additionally, there are solar-powered generators, the most eco-friendly choice, but often more expensive and demand more maintenance than other generator types.

Aside from the various generator types mentioned, you can also use a portable power station to power an air conditioning unit. Portable power stations, also known as battery-powered inverter generators, are devices designed to store electrical power in an internal battery for future use.

Unlike other generators, portable power stations don’t rely on fuel for operation. They have no engine or moving parts, making them quiet, low-maintenance, and free from fire hazards. They are environmentally friendly and safe for indoor use since they don’t emit carbon dioxide. These devices work by converting the battery’s direct current (DC) into alternating current (AC), making them suitable for powering electronics such as laptops and phones.

More importantly, you can use a portable power station to power an AC unit, provided certain requirements are met. For example, you need to calculate specific factors like the watt-hours and total voltage output of your device, the wattage and voltage requirements of your AC, and the amperes your AC will consume. With this information, you can determine if your device can power an AC for an extended period. You can search online for product websites to learn more about the best portable power station for your home.

Can a 3.5 KVA Generator Power an AC?

Yes, a 3.5 KVA generator can power an AC unit, but it depends on the specific generator and AC model. For instance, a 3.5 KVA generator with a maximum wattage output of 2,800 watts should be able to power a typical 24,000 BTU (British Thermal Units) AC unit. However, this assumes that the AC is the only appliance running on the generator. If you attempt to run additional appliances or devices simultaneously, you risk overloading the generator and causing damage.

Can a 12,000-Watt Generator Run Central Air?

A 12,000-watt generator can supply enough power to run a central air conditioner, but the specific requirements depend on the AC unit model. A standard central air conditioner typically needs about 3,000-3,500 watts of power to function. However, newer and more energy-efficient models might only require 1,000-2,000 watts. Therefore, it’s crucial to verify the particular requirements of your AC unit before buying a generator to avoid spending more than necessary.

Can a 10,000-Watt Generator Run Central Air?

A 10,000-watt generator can provide sufficient power to operate a central air conditioner for extended periods. However, it’s essential to remember that the power needed will vary based on the size and efficiency of your AC unit.


In conclusion, choosing the right generator to power your air conditioner depends on several factors, such as the type of AC unit, its wattage requirements, and any additional appliances you intend to run simultaneously.

To ensure you select the appropriate generator size, it’s crucial to calculate the running and startup wattage of your AC unit and consider the generator’s capabilities.

Gasoline, diesel, propane, and solar-powered generators, as well as portable power stations, are all viable options for powering your AC.

By understanding your specific needs and requirements, you can make an informed decision on the right generator for your situation and enjoy a cool and comfortable environment during the hot summer months.

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