Can you help troubleshoot my hot water/high electricity bill issue?

I use an ammeter too. Just installed 2 new 4500w elements. [both operate together]

1 element; 17.8 amps on one wire, 19.9 on the other

1; 18.5 a on one side, 20 on the other.

Seems they should read the same on each wire. Never seem to. Whats up?

100x20/17.8= 112 % so the tolerance on the hot resistance value for elements is maybe (112 - 100)/2 = +/- 6 %, assuming this small sample size of 4 is representative of all 4500 W elements. Probably the actual tolerance is quite a bit wider than 6 %.

Close enough for guvmint wuk!

And the cold [or hot] resistance values for "identical" brand new incand. bulbs is probably all over the map but the hot values may have tighter tolerance limits.

Not much precision required in either case and precision costs money.

http://statpages.org/tolintvl.html

The likelihood that you would get two consecutive element readings identical to within 1 % or 0.1 % is probably close to zero.

And this book
http://www.probability.ca/sbl/
says you're more likely to die in a car accident on your way to buy a lottery ticket than you are of winning that lottery.