In article ,
Jeff Liebermann wrote:

Drivel: US DoE can't figure out how to measure microwave oven power
output.

Jeff-

My impression is that the referenced article refers to efficiency, not
power output. It talks about such things as magnetron filament current
and warm-up time.

Somewhere on the web I found a procedure for measuring power. You heat
a liter of water for a certain amount of time, measuring temperature
before and after. Using a formula, temperature rise correlates to power
output.

I think such a procedure is basic, and don't see how it could be
challenged other than for "hot spots" in an oven. In my case, the oven
has a carousel to compensate.

My old 900 Watt Sharp microwave actually puts out 650 Watts according to
the procedure. I adjust cooking times meant for 1100 Watt units,
multiplying by 1100/650. The food appears to be getting the right
amount of heat.

An old Sharp "Half Pint" is rated for 450 Watts. The above procedure
agrees exactly.

Fred