Portable Generator Sizing and How to Choose the Best Fit

Portable Generator Sizing and How to Choose the Best Fit

So you have decided that you need a portable generator. Now what?

The internet is a glorious place that has millions of options, venues, products and resources. But when it comes time to choose a product, deciphering through so much information then deciding from such a large selection can be tough.

Shopping for portable generators is no different.

Perhaps the best place to narrow your search is by choosing the appropriate size you will need. Start by determining the amount of energy, known as wattage, you will need to power the appliances you have in mind. For instance, a cellphone will be much easier to electrify than a washing machine.

Usage varies greatly for portable generators because they are, as their name suggests, portable. That means these types of moveable power sources can assist in yard work or can be used during camping trips. As an emergency tool, portable generators can even save your family from freezing to death during a winter power outage or can prevent your food from spoiling during a winter storm.

One useful tool that the internet provides is a wattage calculator, however for more accurate calculations you should add them yourself using the specifications for your own appliances. There are many resources that can calculate exactly the amount of juice you will need to keep your house running, to power your leaf blower, or whatever you may need.

Continuous Watt Calculations

It is necessary to determine the watts of anything you will want to be powered by your generator. Take an inventory of everything in your home you would like to use if you had no electricity. Or, for yard work, take an inventory of every tool you would like to use.

For items you already own, an owner’s manual or purchase tag should note the watts that are used. If you do not yet own the items or do not have the necessary information, a simple calculation can help determine how much power you will need.

Volts x Amperes = Watts

For example, a typical microwave uses 1,000 watts. Therefore, it may have 100 volts and 10 amperes.

However, calculating all of the watts you will need is not an entirely accurate number of watts your generator will need.

Portable generator sizing appropriate for you will also need to be calculated with surge watts, which are the watts used to get the motor running of any appliance or item. Once these items have started, they will settle into their ongoing wattage number. For instance, a refrigerator has an initial startup of 2,500 watts, but only uses 1,700 as its ongoing wattage rate.


Staggered startup. You should not worry if your startup wattage is significantly higher than the size of generator you hoped to purchase. You can stagger the plug-ins so that this number remains lower. In other words, it would take much more energy to plug everything in at once than to plug items in one at a time, allowing each to settle to their ongoing wattage before plugging in a new appliance

Important items to power. Although these items may not initially be thought of when calculating important household items, many are necessary to keep your home from being damaged. For instance, a sump pump in the basement may help prevent your home from flooding in the case of nasty weather. Well pumps can also be of importance

Think smart. Substitutions can save you plenty of watts, and in turn dollars since you will not have to buy a larger generator. For instance, use a microwave instead of an oven. Your family can last at least a few days cooking in a microwave, which uses substantially less energy than an oven


With proper planning, your family can have all it needs during a power outage for several days. However, the key to that sentence is planning. It is necessary to know what items you plan on using or powering before purchasing your generator.

Portable generator sizing that is appropriate for your family is ultimately up to you. There is no point in purchasing the largest generator possible if your family only hopes to charge their cellphones during a brief outage.

However, if your area is prone to frequent outages, especially for long periods of time, it may be necessary to buy a larger portable generator to maintain several appliances and items at once.

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