What Size Generator Do I Need? (Sizing Your Needs) 2021 – Yorator

by Johnathan Roos
Last Updated on

For most, power generators are simple devices that supply backup power. While this is true, there are still many different features to consider when choosing the right generator for you. For starters, many fail to answer the question:  what size generator do I need?

There are many factors to consider when choosing the right sized generator for your power needs. One of them is the power requirement in your house. Here, we will be discussing everything you need to know about generators to help you choose the right sized power generator for your home.

Identify Requirements – Starting Watts & Running Watts

what size generator do I need

Before choosing a portable generator, most people ask the question – what size generator do I need? This question can get a bit technical, and many new shoppers get stuck while looking for the correct answer. But the good thing is that the answer to this question is pretty simple and easy to understand. Let’s walk through it step-by-step so you’ll know exactly how to figure it out.

To know what size generator you should have, you need to follow these three simple steps:

  • First, you have to collect information on both the running and starting electricity needed for all of your appliances.
  • Then, you have to ensure that the power information you collected is represented in Watts.
  • Finally, figure out how many appliances you will want to run at any specific time.

So let’s now shed some light on it in detail. We are going to calculate the necessary wattage to determine the size generator you require.

1. Collect Running and Starting Power of Your Appliances

First, you have to determine the running wattage, also known as continuous wattage or rated wattage, and the starting wattage, also known as the peak wattage, needed for each of your appliances. In some instances, these will be the same such as for small appliances like TVs, lights, laptops, etc. For all these appliances, the starting and running wattage are the same.

But you’ll also find that, in many cases, the starting wattage and running wattage for an appliance will vary drastically. Appliances with electric motors or heating elements will require a starting wattage that is 3 to 4 times (or even more) than the running wattage. These types of appliances include air-conditioners, electric deep fryers, fridges, microwaves, hairdryers, grinders, pumps, drills, coffee machines, saws, etc.

So you’ll have to collect the starting and running wattage information for your appliances to determine the capacity of the generator you need. If you make a mistake here and underestimate what you’ll need, then you won’t be able to run some of your appliances with your generator, at least not all at one time.

2. Ensure Power Information is Represented in Watts

In the second step, you’ll need to make sure your information is in terms of watts. If some of your information is in the form of Amps, Kilowatts, or Horsepower, then you’ll need to convert these forms of power into watts. You can calculate these manually or with the help of an online converter. To calculate it manually, the following information will be very helpful:

  • 1 Amp= 240 Watts
  • 1 HP= 746 Watts
  • 1 Kilowatt= 1000 Watts

3. Identify Amount of Concurrent Running Appliances

In the final step, you have to figure out how many appliances you need to run at one time and how much power they will consume. According to that calculation, you’ll have to choose a generator that has a high enough output to handle the demand. Let’s go through some examples to make things clear:

Example 1: Suppose your air-conditioner requires 2300 watts starting power and 1000 watts running power. If this is all you want to run, then you have to choose a generator that has a capacity of at least 2300 watts of power or more.r or more.

Example 2: Suppose you have a water pump in your house that consumes 7200 watts power at starting, and it reduces to 1800 watts for the running power. So, in this case, you have to have a generator of at least 7200 watts power or more.

Example 3: Now, suppose you want to run more than one appliance at a time using your generator. Then you will have to consider the power each appliance needs and sum up these values to determine the required generator capacity. If you need to run your air-conditioner, TV, mobile phone, and tablet at the same time, then the wattage calculation would be as follows:

Appliances Running Wattage Starting Wattage
Air-Conditioner 1000 2300
TV 200
Mobile phone/Tablet 100

So you will have a total wattage requirement of 2600 watts (2300+200+100). In the calculation, you will have to sum up the highest wattage for each of your appliances. So, in this case, you have to choose a generator that has a wattage capacity of at least 2600 watts or more. You can get an idea of required wattage for different appliances from the wattage estimation table.

Using the Total Amount of Watts

There are three different methods to figure out the starting watt and running watts of your devices. Adding up those numbers will give us an estimate to help answer the question of what size generator do I need.

Most home appliances need more starting power than the amount of power required for running continuously. From the device’s user manual or searching on the web, you can know their starting watts. But for running watts, you can follow one of three methods from below.

  • First Method

This is the easiest and quickest method of all that involves checking the labels of the appliances. You will see that it includes some basic information like input/output voltage, current consumption, wattage, etc. This information is also available on the user manual or gets it searching the web.

  • Second Method

Not all of the devices come with a label that states the wattage. This second method requires figuring out  the amperage rating of the device in any way. After that, find the standard voltage rating in your area and multiply the number with the amp to know the watts.

  • Third Method

The third method involves purchasing a calculating power device. This device is put in between the desired home appliance and the power line. After turning on the appliance, you will see the power it is consuming on the LED monitor.

Different Generator Sizes

Using one of the three methods above, you can figure out the power requirements for your home and decide on a specific generator. There are many different types of generators on the market, each with different power requirements and in different sizes. Here are a few:

1. Very Small – Ranging from 900 to 2000 Watts

This type of generator is mainly used for recreational uses such as camping or gathering outdoors. It is capable of running a few small appliances, charging your phone, or running a large appliance. No other generators are as portable as this one making it convenient for RV owners and small homeowners.

2. Small – Ranging from 3000 to 4000 Watts

Small generators are very portable and can power basic devices. This makes them suitable for homes with little requirements. You can power a refrigerator, a TV, and a microwave at the same time, even after considering the starting watts.

3. Medium – Ranging from 6000 to 7500 Watts

If you want to run some more appliances or run with more runtime, you should consider medium sized generators. With such a generator, you’d be able to power an entire house during a power outage.

4. Large – Ranging from 7500 to 15000 Watts

With large generators, you won’t have to choose between the number of devices or runtime. These generators are a bit harder to use on your own and you may need extra help. Overall, they are great for powering an entire household for a long period of time.

Final Thoughts

With the information provided in the buying guide, we hope that you have all the information you need to decide what size generator you need.  After calculating your power requirements and desired runtime, you are one step closer to a reliable source of backup power.

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