As summer heats up, many homeowners wonder if their portable generator can handle the load of running an air conditioning (A/C) unit. The short answer is yes, but it's essential to understand the nuances of power requirements and proper setup.
Air conditioners have two critical power ratings: starting watts and running watts.
Starting Watts: When an A/C unit first turns on, it requires a surge of power to get the compressor and fan motor running. This initial burst, known as inrush current, can be two to three times higher than the unit’s normal operating power. For example, a typical 10,000 BTU window A/C might need around 2200-3000 starting watts.
Running Watts: After the initial surge, the A/C settles into its normal operating mode, consuming less power. The same 10,000 BTU unit might run continuously on about 1200 watts.
Portable A/C Units
Portable AC units are versatile and designed for cooling individual rooms or small spaces.
| Unit Size | Starting Watts | Running Watts: |
| 8,000 BTU | 1,200 - 1,500 | 800 - 1,000 |
| 10,000 BTU | 1,500 - 2,000 | 1,000 - 1,300 |
| 12,000 BTU | 1,800 - 2,500 | 1,200 - 1,500 |
| 14,000 BTU | 2,200 - 2,800 | 1,500 - 1,800 |
Learn more about portable A/C wattage.
Window A/C Units
Size Range: Typically between 5,000 - 25,000 BTUs
Cooling Capacity: Suitable for single rooms or small spaces
| Unit Size | Starting Watts | Running Watts: |
| 5,000 BTU | 1,200 - 1,500 | 500 - 700 |
| 10,000 BTU | 2,200 - 2,800 | 900 - 1,200 |
Central Air Conditioning Units (Whole House Systems)
Central air conditioners are typically sized by tons, with each ton equivalent to 12,000 BTUs. The right size depends on the square footage of the home and regional climate.
| Unit Size | Starting Watts | Running Watts: |
| 2-Ton Unit (24,000 BTUs) | 3,500 - 4,000 | 2,000 - 2,500 |
| 3-Ton Unit (36,000 BTUs) | 4,500 - 5,500 | 3,000 - 3,500 |
| 4-Ton Unit (48,000 BTUs) | 5,500 - 6,500 | 3,500 - 4,500 |
| 5-Ton Unit (60,000 BTUs) | 6,500 - 7,500 | 4,500 - 5,500 |
To ensure your generator can handle your A/C, you need to select the right size generator, one that can provide enough starting watts. If your A/C requires 3000 starting watts, you'll need a generator rated for at least that much, plus any other appliances you plan to run simultaneously. For a margin of safety, consider connecting a generator with a slightly higher capacity than your calculated needs.
A useful device that can help is a soft start capacitor. This component reduces the inrush current required to start the A/C by slowly ramping up the power, rather than demanding a massive surge all at once. By installing a soft start capacitor, you can significantly lower the starting wattage requirement of your A/C unit. This means your generator doesn’t need to be as powerful, making it more feasible to run the A/C efficiently.
Check Your A/C Specs: Look at the label on your A/C unit to determine the exact starting and running wattage requirements.
Match Generator Capacity: Ensure your generator can handle the combined starting watts of all appliances you wish to run, including the A/C.
Consider Soft Start Technology: Investing in a soft start capacitor can make your setup more efficient and reduce the strain on your generator.
Always adhere to the National Electrical Code (NEC), which includes requirements for safe generator installation and usage. Key points include ensuring proper grounding and using a transfer switch to prevent backfeeding into the grid.
In conclusion, while a portable generator can run an A/C unit, it's crucial to understand the power demands and use appropriate technology to manage those demands. By carefully selecting your generator for air conditioning and considering a soft start capacitor, you can stay cool even during a power outage.
Click here for everything you need to know about using a portable generator.
Yes, a generator can run an air conditioner, but it must be powerful enough to handle the AC’s starting wattage (which can be several times the running wattage). It's essential to ensure the generator has adequate capacity to prevent overload.
The size of the generator depends on the air conditioner's power requirements. A small window AC might only need a 2,000 to 3,000-watt generator, while a central air system could require 10,000 watts or more. Always check the AC’s specifications and match them with the generator's wattage rating.
Yes, a whole house generator can run an air conditioner, especially if it’s sized to handle the total power demands of your home, including the AC. Many whole-house generators are designed to manage high-wattage appliances like central air conditioners.
The size depends on the type of AC unit. Window units typically require a 2,000–4,000-watt generator, while larger central air conditioners may need at least a 10,000–12,000-watt generator. Always check both the starting and running wattage requirements of your AC to choose the right generator.
Yes, you can run an AC on a portable generator if it has enough wattage to support the unit's power requirements. It's essential to ensure the generator's output meets or exceeds the starting and running watts of the air conditioner to avoid power issues.