How Much Power Do I Need from a Generator? - The Best Portable Generators

The most important factor in choosing a generator is to ensure you choose one with the right amount of power. The article below will help you figure out what the right amount of power is for you.

Starting Watts vs Running Watts

Generators have two power ratings that you need to understand – starting watts and running watts.

Starting Watts or Initial Watts or Maximum Surge: Appliances typically need a boot in power to get them started. So, on a generator, starting watts is a temporary amount of additional power provided by the generator to help start appliances.
Running Watts or Continuous Power Rating: Running watts is the amount of electric energy the generator can deliver continuously.

Calculating Your Power Needs

As mentioned above, when they first start, several appliances require an initial boost of energy. Then, as they continue to operate, their power needs drop. For instance, refrigerators usually require around 1,200 watts of electricity to start, whereas they only require a continuous supply of 20 watts of power.

To calculate your power needs, first decide on the appliances you want to run. Then decide on the appliances you want to operate at the same time. So, while you might want to be able to use both your coffee maker and blender, you might be perfectly happy to use only one of them at a time (to reduce the amount of power you need at any moment).

Next, add up the running watts from all the appliances you want to operate at the same time. While both starting watts and running watts are important, you only need the starting watts for a few moments for each appliance so we can ignore this for now.

Typical Appliance Power Usage

Lets look at some examples of the type of power used by common appliances. Note that these are examples only and you really need to check your devices to see what power they use:

Toaster 700 watts
Blender 550 watts
Laptop 250 watts
Coffee maker 1000 watts
TV 150 watts
Refrigerator 700 watts
5 to 10 lights 250 watts
Smartphone charger 20 watts
Sump pump 900 watts
Dishwasher 1500 watts
Air conditioner 1000 watts

How Many Appliances Can A Generator Run?

Looking at the examples above, we can roughly, very roughly, start to understand how many appliances a generator can run, given its running output rating.

1000 running watts will allow you to run one or 2 appliances simultaneously
2000 running watts will allow you to run 2 to 4 appliances simultaneously
3000 running watts will allow you to run 3 to 6 appliances simultaneously
Generally, you need at least 2,000-8,000 watts to supply your household appliances.

Power Usage Is Not An Exact Science

Hopefully by now you will see that the amount of power you will need is NOT an exact science. Unless of course you know exactly what appliances you plan to operate and you know exactly when you plan on using them. A very unlikely scenario indeed. So, do your best, and leave yourself some wiggle room. No one else can tell you exactly what you will need. For some people, in a power outage at home, they must still be able to run their washing machine and air conditioner and dish washer (all of the appliances are very power hungry). For others, they can skip all of that while the power is out for a few days and be happy with lights in a few rooms, a laptop, their phone, a coffee pot and a toaster. The important thing is to be clear about what you want.

Let’s come back to the starting watts briefly. So far, in your calculations, you have ignored this figure. For the most part, if your generator can manage your running power needs, it is likely to be able to handle your start up power needs. However, if you want to run some very hungry power appliances, then check their starting watts and make sure the generator you buy can handle the surge capacity needed.

Generator Sizing

You can see that what is a big generator for one person may not be to another. However, across the internet. generator sizes loosely fall into the following categories: