Inverters for Microwave Ovens

14 July 2022  |  Paul

Selecting the appropriate inverter for use with your Microwave Oven

A common problem we see when customers are looking to purchase an inverter is confusion over selecting the correct power rating for their application, and this is especially true when it comes to running microwave ovens. Microwave ovens are specified with an output power rating in Watts (perhaps 700W, 800W or 1200W) which relates to the amount of energy that can be transferred to the food, and you would be forgiven for thinking that an inverter with an equivalent power rating would be adequate. However, since there is an inherent inefficiency to any energy conversion, the input power required to run the microwave is higher than the output power, and since microwaves are relatively inefficient, this difference can be quite considerable. So, to run a microwave oven you actually need an inverter that has quite a lot more power than the rated output power of the microwave.

microwave oven inverter

In use, the efficiency of the average microwave oven in converting electrical energy into electromagnetic microwave energy can be as low as 50%, with the more energy-efficient models reaching around 64%. This means they can require almost double the amount of power going into the unit to produce the specified output power, and a 700W microwave may need up to 1400W of electricity to operate.

Of course, different brands and models will differ in their efficiencies so it is important to check your microwave's input power rating which can normally be found on the back of the unit on the specification label.

As you can see, my home microwave's rated output power is 700W but the oven needs 1150W of input power to work, which is quite energy efficient when compared with the average. If I had brought an 800W or 1000W inverter to power my microwave I would keep getting an overload problem and the inverter would shut down (this is where the appliance is trying to draw more power than the inverter can provide and it turns off to prevent overload and damage). I now know that I need to select an inverter able to provide at least 1150W, and preferably slightly more so as not to run the unit at its maximum capacity, so I would probably go for a 1500W inverter or higher. Microwaves can be run from Pure or Modified (Quasi) sine wave inverters so it is only the output power that I need to be concerned about when picking my inverter. 

This issue of input power versus output power is something to be aware of with a lot of electrical products including hairdryers, heaters and other appliances where an output power might be advertised. It's always worth checking the input power on the product label or in the product documentation and rating your inverter according to this, not the output power.

We hope you have found this article helpful but if you need any further help please contact our sales team.

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