I'd like to figure out how much I'm spending on energy,  per appliance.  Does anyone know of an inexpensive  device I can use to see how much electricity an item  (i.e.  my water heater,  or a/c heat pump)  is using.

Thanks

if they're electric you can use kill-a-watt to montior usage. You'll have to use your local rate to calculate dollars & cents..

http://en.wikipedia.org/wiki/Kill_A_Watt

Problem with the Kill-a-watt is that you have to plug in the appliance. I can't plug my water heater or a/c unit into the killa a watt.

I was hoping that there was something that I could attach to the electrical line leading to the water heater that would somehow read the power passing through.

You can measure the current if you can put a coil pick-up around one of the wires. Then you can assume the voltage based on the nominal source voltage, or measure it with a voltmeter.

Lee

The advantage of the Kill-a-watt is that it works for intermittent loads and accounts for power factor.

I'm thinking about adding a solar water heater to my home. I'd like to figure out how much power on a daily, or monthly basis that the current electric water heater uses.

So far I haven't been able to figure that out. The kill a watt is great but wouldn't work for this application - no way to plug the water heater into it.

If your water heater uses standard electric resistance heating elements, you can get an electric hour meter rated for the supply voltage and connect one hour meter to the wiring that feeds each element (assuming your tank has two heating elements, it may just have one). Based on the watt rating of the heating element(s) (typically 3000 to 4500 watts), you can roughly calculate your watt-hour electric usage per month by just multiplying the element rating times the hours it has been energized. Your water heater owner's manual should have the watt rating of the element(s). If not, possibly they are marked. If not marked, the wattage can be calculated from the measured resistance of the heating element and the measured supply voltage.

Bingo ! Thanks arkie6

Did a quick google search under "hour meters" and they seem to be about $25-$30, if I'm looking at the right thing

So I suppose they have a couple of wires that just connect to where the wires for the water heater heating element connects and the meter runs like an odometer. Seems pretty simple.

Any suggestions on make or model?

Take a look at Emonitor by PowerHouse Dynamics.  It is expensive, however I have every circut in my electric panel being monitored.  I got it to track what my Geothermal system was costing me and to see if it would be as effective as designed.  It has already saved me a boat load on the water heater.  I can look & see what each room is using in electricty.  No only does it tell me how much wattage and kiloWatt Housrs I have used, it also converts it in to cost using my local electric rate.   It also sends me Alert messages via text & email for things like loss of power,  circuts on too long ect. ect.

I love it and think it is well worth the money if you want to see where all of your electrcity is going.

thanks nhgeo. I'll look into that.