What Will 12000 Watt Generator Run?

There are many factors to choosing the right generator that can power your whole house. Count the appliances you’ll use. 

So, what will 12000 watt generator run?

A 12000-watt generator can pretty much run anything in an average resident. Generally, an average residential setup requires from 5000 to 10000 watts of power. Also, it depends on your home appliances such as AC size or heat pump power rating. So, to measure the required power you need to calculate all your home appliances’ wattage. 

Follow the article to know everything you need to run your house with a 12000-watt generator. 

Will A 12000 Watt Generator Run My House?

Yes, a 12000-watt generator will efficiently run your house. Still, to be sure, list down all of your home appliances and calculate their running and starting wattage. Let’s see the starting and running wattage of some essential appliances.  

Appliance ListRunning Power (watts)Starting Power / Surge Power (watts)
Ceiling Fan60 W70 W
Central AC (1 ton) 900 – 1,500 W4,500 W
Central AC (2 tons)2,000 – 2,500 W7,000 W
Central AC (3 tons)2,900 – 3,500 W10,500 W
Central AC (4 tons)3,900 – 4,500 W14,000 W
Window AC (10,000 BTU)1,200 W3,600 W
Window AC (12,000 BTU)3,250 W9,750 W
Heat Pump4,700 W4,500 W
Electric Water Heater3,000 – 6,000 W0 – 2,200 W
Light Bulb(Common / LED)9 – 75 W0 W
Night Light1 W0 W
Tube Light22 W0 W
Dishwasher1400 W1450 W
Microwave600 W0 W
Router600 W1500 W

Now, add up the running and starting wattage of the appliances and measure if a 12,000-watt generator can run them. You can also wonder about the capability of a 3000-watt generator

Also, the size of your house matters. Let’s see how. 

  • A 1,000 – 1,500 sq ft house: 6,000 – 8,500 watts generator. 
  • A 1,500 – 2,000 sq ft house: 8,500 – 10,000 watts generator. 
  • A 2,000 – 2,500 sq ft house: 10,000 – 14,000 watts generator. 
  • A 2,500 – 3,000+ sq ft house: 18,000 watts generator or larger. 

A 12000 Watt Generator for Heat Pumps

Yes, a 12,000-watt generator will run a heat pump. However, it can run a heat pump up to 3 tons. And if you only run a heat pump with the 12000-watt generator, then it can run up to 4 tons. 

On average, an air source heat pump needs a power of 545 watts to 7,500 watts. So, a home standby generator of 17 kW power is a wise choice for efficient heat pump runtime.    

A 12000 Watt Generator for Air Conditioners

Yes, a 12,000 Watt generator will run an air conditioner up to 3 tons at its maximum capacity and 100% load. And if you run only the HVAC system, then you can run up to 4 tons of AC. 

AC SizeTime Estimation at 50% Load
2 Ton4 – 6 hours.
3 Ton3 – 4 hours
4 Ton2 – 3 hours (not recommended)
Central Air1 – 3 hours (not recommended)

This is a rough estimation, based on 7- 8 gallons of fuel tank capacity and the 2 – 2.5 gallons-per-hour consumption rate.  

For A House with 2 Ton AC Unit:

A house with a 2-ton AC will easily run on a 12000-watt generator as long as there are no high-wattage appliances running simultaneously. A 2-ton AC unit uses about 5,000 to 7,000 watts to start and 2,000 to 2,500 watts to run. 

For A House with 3 Ton AC Unit:

A house with a 3-ton AC unit requires 5,000 to 10,000 watts to start based on types and SEER rating. So, a 12,000-watt generator will run a 3-ton AC. But again, you cannot run any other appliances as it will take about 80 to 85% load of the generator. 

For A House with 4 Ton AC Unit:

Although it is possible to run a 4-ton AC unit with your 12,000 generators, it’s not recommended. Because a 4-ton AC requires 10,000 to 14,000 watts to start and 3,900 to 4,500 watts to run. 

So, starting the AC will be an issue as it might damage your generator’s circuit breaker. But once it is started, you should be fine for 2 to 3 hours. And be careful not to use any other appliances simultaneously. 

For A House with Central AC Units:

A house with central AC units also cannot be run on a central AC. A central AC unit requires a large amount of power to start the compressor. Although it can be run as it requires only about 2,000 to 3,500 watts, it is not recommended. Especially if you have other high-wattage appliances.  

How Long Will A 12,000-Watt Generator Run

On average, a 12,000-Watt generator will run for straight up around 10 hours based on the appliance, fuel capacity, and fuel efficiency. If you use high-wattage appliances, make sure not to use multiple ones to avoid damage. Choose the best 12,000-watt generator.


So, there it is, all you need to know about what will 12000 watt generator run. Now, consider widening your option if you have a larger house with various appliances. Or think about more efficient fuel for your generator.

Frequently Asked Questions (FAQs):

Can You Run A Generator 24-Hours A Day?

You can if you have a constant supply of fuel. However, some fuels are hard to come by so often. So, it’s not good to run a generator 24 hours a day, on your money.

Should You Leave A Generator On All Night?

No, you should not because it leads to carbon monoxide poisoning. A portable generator emits extensive amounts of carbon monoxide and it might get toxic to the environment. 

Can You Overuse A Generator?

No, you cannot as it will overload a generator’s power capacity and short the circuits. It even can lead to fire hazards and deaths

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