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How do I choose the right generator?


Choosing the right generator for your needs can be a confusing process if you’ve never used one before. Whether you need a portable generator for camping trips, power for your mobile business or a full backup power supply for your entire home, simply picking the cheapest option may leave you with limited power capacity and unable to run the appliances you need. Equally, overestimating your power requirements can mean unnecessarily high initial costs.

Cummins Onan 5.8 HGJAD Generator
Cummins Onan 5.8 HGJAD Generator

In many cases, to simplify the process, it is suggested that we calculate the wattage requirements of all the appliances we intend on running at any one time. To do this, you will need to:

  1. Create a list of everything you need to run at any given time
  2. Find the starting watts and running watts of those appliances – exact figures can be found on the appliance’s manual or identification plate, or online if you can’t find those. A wattage metre can also be used to check each appliance if you can’t find its information.
  3. Then, calculate the combined running wattage for all of the appliances you will be using at the one time.
  4. Finally, identify the appliance with the highest starting wattage and add this to the total running wattage of all appliances.

For example, we want to run a dishwasher, a 1,000watt microwave and a fridge at the same time so make the following list:

Appliance Running watts Starting watts
Dishwasher 1,500 1,500
Microwave 1,000 0
Fridge 700 2,200
Total: 3,200

The combined running wattage of the three appliances is 3,200watts and the fridge has the highest starting watts at 2,200watts. So: 3,200 + 2,200 = 5,400watts. We can therefore look at generators with an output of 5,400watts or more.

WH2400i Digital Inverter Generator
WH2400i Digital Inverter Generator

It is however important to note that this can sometimes be misleading. If you have numerous appliances, how often will you be using them all together? Equally, with smaller generators it’s easy to go over capacity so often it’s best to choose the next model up as wattage does not increase in large increments from machine to machine – it’s only with large, commercial machines that going up a model will mean a big jump in wattage and therefore price. These various factors are why we like to work in a different way with our customers to calculate the wattage and consider all factors to ensure they get the best machine for their uses.

It’s always best to speak to an expert to determine how much power your generator requires and explore the most efficient generators for your application.

To discuss your individual requirements and take the headache out of finding the best generator, speak to Brett directly on 1300 278 655.

2 thoughts on “How do I choose the right generator?

  1. I hadn’t thought about creating a list of everything I need to run as I look for a generator. It definitely makes sense that doing this can help you get a unit that has the right wattage for your appliances and that will not overheat or have electrical failures. Personally, I would want to educate myself a little more on how they work and who to call to help me keep it from causing accidents and provide the energy I need in an emergency.

  2. Hi John, adding the total appliance KW’s is a starting point to get an idea of what size you will be looking at. It can also complicate things when you add starting KW’s into the equation. In a lazy kind of way I simplify this by acknowledging the fact that most small generators really only come in set sizes so once you work out your load your choices are really only of one or two sizes.
    However with the larger machines from about 10KVA I would recommend leaving the sizing to expert and discussing with them the options they suggest as currently there are a lot of salesmen both on online and offline that will give you advice that specifically sells their equipment and whilst sized right may be unsuitable for your application, and as that gets into a whole other discussion I’ll leave that for another posting.

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