You may think you have no use for a generator, unless you experience a power outage in your area. The power outage can be for any reason, including maintenance, strong winds, turbulent weather, etc. Therefore, it is best that you get a generator to serve as a backup power source that keeps you covered when the power suddenly goes out.

How do I Know What Size Generator to Buy

In the market, you can find a myriad of generator brands and models out there, each with their special features and specifications. More so, each generator has a certain size or power rating that determines how much load it can bear. Whenever you purchase a generator, you have to pay special attention to its size, and this guide tells you all about determining what size generator you need.

Choosing the Right Size Generator

There are several types and models of generators, and they are also categorized according to their fuel types. Some of the common types include gasoline generators, diesel generators, solar generators, inverter generators, etc. However, size also plays a major role in this decision, and here is how you can go about it.

List Down Appliances You Need to Run

First and foremost, you need to list down all of the small and large appliances and devices that you want to run on the generator. In the case of shorter power outages, people choose to keep most of their appliances off, so they can make do with a smaller size generator too. For instance, you may choose to keep your air conditioner on along with the lights and televisions, but your washing machine, microwave, and other appliances will be off. If you want to prepare for longer power outages often caused by bad weather, you can choose to include all of your essential appliances so that you don’t have to worry about cooking, reheating food, washing your clothes, or any of your daily functions. Other than this, you can also list down smaller appliances, such as lights, fans, computers, routers, or other gadgets around your home.



While you are on this step, you should also determine the number of appliances that will be running at the same time, or those that are always running. These appliances, and their subsequent power ratings, will give you an accurate representation of how much power you need your generator to provide. For instance, say you have four lights running at 10W, a computer running at 20W, an air conditioner with a starting wattage of 2000W, a television running at 30W, and your router running at 5W. These are the appliances that would be on at any given time, and other appliances would be used as per their need. When you add all of these values, you get 2065W. So, if you have a generator that supplies anywhere between 2000W and 3000W, you won’t have to worry about anything.

How do I Know What Size Generator to Buy - generator

Get Power Information for your Appliances

Once you have made a list of the appliances that you want to run on the generator, you need to gather information regarding the power rating or output of each of those appliances. For this, you will need to check the back or sides of these appliances for their power information, and you need to find out the starting peak watts and the running watts. These two bits of information will tell you how much power is required to start the appliance and keep it running constantly. For smaller appliances like televisions, lighting fixtures, computers, routers, and laptops, the starting and running watts may be same or quite close, because they don’t require a lot of power to start. However, larger appliances like refrigerators, irons, microwaves, coffee makers, air conditioners, and much more, the starting wattage may be 3-4 times higher than the continuous wattage.

If you want to run all of these appliances on your generator, then you will need to add up all of the starting wattages together to determine how much load the generator will have to bear when you turn it on. Make sure to get all the readings in the same unit, which should essentially be watts. If any of the readings are in amperes, you can multiply them with the voltage rating of the appliance to get the power output.

Calculate the Total Power Requirement

While the starting and continuous power rating for all your appliances would be in watts, the total power requirement would have to be calculated in kilowatts (kW) or kilovolt amperes (kVA), since the generators’ sizes and power ratings are shown in these units. Once you have added all of the readings from the previous step, simply divide the sum by 1000 and you will have the total power requirement in kVA. Suppose your total power requirement is 2500W, or 2.5 kVA. This means that you can make do with a 2.5 kVA generator in your home. Since most of your appliances have a higher starting wattage, the actual power utilization may not be higher than 1800W or 2000W at any given time. If you are looking to buy your generator ASAP, you can check out these reviews and take your pick.