I cant answer you but a meter that is fun and usefull is a Kill-A-Watt
apx 25$, it lets you plug in an apliance and measures very accuratly
time, watt, amp, power factor, Kwh used and the hours, V. Hz and more,
you will easily be able to audit usage of anything 120v you plug into it
and find the hogs to show the hogs. It is also very good on low draw
equipment on standby, such as the tv off. It measures over a 100 hr
period. You would be suprised how older things can cost 1$ a month un
used but newer "energy star" rated can cost 1 penny to keep plugged in a
month, It helped me get my electric to 14-20 a month from 50. It also
made me get a new frige that uses 1/6th the power. They have been
independantly tested very accurate, somethimes Radio shack has them.