kWh / KW ????

I see on my bill I used 703KWH last month. My water heater has a 4500 watt (4.5KW) element in it. If I ran the unit continually for 1 hour how would I calculate the KWH?
Thanks,
Mark

[Robert Fogt]

As its name implies, kilowatt hours is indeed kilowatts * hours.

4.5 kilowatts * 1 hour = 4.5 kWh

thx for helping with my energy econ homework

Thanks for helping me with my homework too =D

thanks for doing my homework

that ******* is wrong! i failed my test because of him!!!

Originally Posted by Robert Fogt

As its name implies, kilowatt hours is indeed kilowatts * hours.

4.5 kilowatts * 1 hour = 4.5 kWh

Thanks. Your answer help me a lot.

OK...all this is very confusing...heres what i think...KWH Kilo=1000 watts=watts...kwH=1000 watts...a 60 WATT light that runs for 24 hrs is 60x24= 1440...which is 1.44 KWH's...if it only runs for 12 hrs its 60x12= 720w= .720KWH??? No?

[JohnS]

Originally Posted by Unregistered

OK...all this is very confusing...heres what i think...KWH Kilo=1000 watts=watts...kwH=1000 watts...a 60 WATT light that runs for 24 hrs is 60x24= 1440...which is 1.44 KWH's...if it only runs for 12 hrs its 60x12= 720w= .720KWH??? No?

Your math is correct.

I would like to correct "kwH=1000 watts" A kilowatt-hour is 1 kilowatt (1000 W) used for one hour.

Kilowatt is a measure of power, a kilowatt hour is a unit of energy, which is the product of power and time.

1 kW = 1 kW consistent for 1 hour, or 1 kWh
1 kW = 1000 J / s = 1 kJ / s
1 kWh = 1000 J / h = 3.6 kJ / h
kW (kilowatts), kWh (kilowatt-hours), J (Joules), s (seconds), h (hours), kJ (kilojoules), mJ (megajoules)
But if you ant to find how much power was consumed in an hour, then you multiply 1 kWh times 3600. You can look above to find conversions to Joules per second, and, including the units, you find that the two time units cancel out each other:
kWh / kW = (1000 J / h) / (1000 J / s)
= (3600000 J / s) / (1000 J / s)
= (3600000 J / s) * (s / 1000 J)
= 3600

Just some prefixes for units if you ever want to know.
(f) fempto = 0.000000000000001
(p) pico = 0.000000000001
(n) nano = 0.000000001
(micro symbol) micro = 0.000001
(m) milli = 0.001
(k) kilo = 1,000
(M) mega = 1,000,000
(G) giga = 1,000,000,000
(G) tera = 1,000,000,000,000
(P) peta = 1,000,000,000,000,000

For your information

If anything is wrong, tell me now and prove it. I always want to be right.

Oh, and Mark, the heater used 4.5 kWh, and it will consume 108 kWh daily if you leave it on 24/7.