Originally Posted by OKnative
Thanks for your question. I don't know how to determine the difference. I just go by what the label on the microwaves say. They don't tell me what is electrical power and what is cooking power.
The 1500W label says "input 120V, 60 Hz single phase 1500W" then under that it says "output 950 W 2450 MHz".
The 900W says "120 Vac 60Hz 1350W 900W frequency 2450MHz.
I don't know how to decipher all of that into what is cooking power and what is electrical power of each of them. Can you?
I was concerned that was the case because I'm not familiar with any residential microwaves that go to 1500 Watts of cooking power. That was the red flag that caught my attention. If they exist they would be rare, and it would be even more rare to end up in an RV because of the electrical power they would require.
Microwaves are usually rated by cooking power. Large ones around 1000 watts are very common, which require around 1500 watts of electricity. You appear to have a 950 Watt microwave that pulls 1500 watts of electricity.
The 900 Watt cooking power unit you list uses 1350 watts of electricity. You'd only be saving 150 watts, which really isn't that much.
We use a 700 Watt microwave in our van very often, and it pulls just above 1000 watts of electricity. In general most microwaves pull 50% more electrical power than their cooking power; give or take a little.
Another important factor to consider is that when you use a lower-power microwave, you will likely end up running it longer to get the same job done; so essentially you will partly offset some of the lower power you gained. Granted it's easier on batteries to go as low on power as practical.