How Many KW Generator Do I Need? This Calculation Will Help You

by Johnathan Roos

A common question to ask yourself when buying a generator is “how many kW do I need?” This refers to the size required for the generator to run power to your devices. In this article, we will discuss how you can calculate the power requirement of your house or office and buy a generator.

What is a kW?

kW is the short form of a kilowatt, and it means 1000 watts. If your generator produces a total of 1000 watts every hour, it can be rated as 1000 kWh or a thousand kilowatt-hour. While most household appliances do not use up entire kilowatts, it is a good idea to have a generator that does so that you can run all your appliances with a single device.

How to Calculate the Total kW of Your Devices?

Using multiple methods, you can calculate the total power consumption of your house. After completing the calculations, you will get a single value in kilowatts so that you can buy a generator accordingly.

You have to keep in mind that finding the size generator for your house or office depends on a number of factors.For starters, you have to consider how much backup power you will need in case of a power outage. You will also want to consider whether you are looking for a standby generator or one that operates on natural gas.

Now, let’s see all the ways to calculate the power requirement of your house.

Method 1

Check the labels of your appliances. Look for information such as input/output voltage, current consumption, wattage, etc. You can also find this information from the owner’s manual of the device. There are also many sources on the internet to tell you the general wattage of common household items.

If the device uses 300 watts and you run it for 5 hours a day, multiplying both numbers will give you 1500 watt-hours or 1.5 kWh per day consumption. Without multiplying, the amount will be 300 watts per hour.

Method 2

If you don’t see any label or can’t get the information above, look at the amps rating on the device. See how the amps your device is consuming.

Multiply the amp-count and voltage. The standard output voltage for most countries is 120V. The final calculation will be in watts.  If your device has a label with 6.5 amps and 120 volts, it will mean that the device consumes 780 watts per hour.

Method 3

Use a power meter. Connect the meter to your device, plug it in a wall outlet, and it will show you the power consumption rating of the device.

What Size Generator Do I Need using Peak and Running kW?

How Many KW Generator Do I Need

If you have already measured and calculated the total power consumption of your house, 80% of your task is done.

Here are some other factors to consider when choosing which generator size is ideal for your home.

Peak kW:

Some appliances require more power to start than to run. For example, a refrigerator, air conditioner, water pump, etc.  A water pump can run on 300 watts per hour, but the generator will need to provide 1100 watts at the beginning.

Running kW:

You can follow one of the three methods mentioned above to find out the running wattage count of your home or office appliance.

Regardless of peak kW or Running kW, a general rule of thumb is choose a generator that supplies power beyond your needs. Remember, larger generators generally produce more power. So what this means, is that if after calculating your home’s power requirement and you find that it would take 100 kW to run your entire household, then you would want to upgrade to a generator that can produce more than that.

Final Steps

If you want a generator for the whole house or office, calculate the power consumption of the major appliances and make an estimate. Calculating all the items can take a lot of time.

For running a selected number of devices, you need to make a list and separately check their power consumption. For example, you want to use a freezer, water pump, and a TV. 1280 starting wattage with 400 running wattage, 1100 starting wattage with 300 running wattage, and 200 running wattage are the power rating of the devices.

For such requirements, you can buy a 2000W or 2 kW generator, and start the items one by one. Starting all of them at the same time is not recommended.

Frequently Asked Questions

Below are some answers to the most frequently asked questions.

What can a 100-kW generator power?

See the specifications of the appliance that you want to run and see its starting power rating. If it matches your generator’s rating, you can power home appliances or office equipment.

What can a 2kw generator run?

A 2 kW or 2000-watt generator can generally run a 500-watt deep freezer, 650-watt microwave, a few lights, or something like these. It is perfect for camping or running small home appliances that don’t need an initial voltage spike to start.

Will a 20kW generator run my house?

A 20-kW generator can power some but not all appliances in your home.

How many kW is required for a house?

Generally, a mid-sized home can use a 20-kW generator to meet the emergency situations, or a 100-kW generator to fully function for as long as you want.

Final Thoughts

Most homeowners choose to leave these concerns to their electricians. When it comes down to it, jobs such as installation and maintenance are best left to the professions. But this doesn’t mean you shouldn’t be knowledgeable about the topics at hand. Knowing your household power requirement is something that all homeowners should look into. With the easy-to-follow steps described above, you can easily calculate your home’s power requirement and are one step closer to knowing everything you need to about power generators.

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