Aquarium heaters pulling more electric than advertised

[AJStyles]

Has anyone noticed their aquarium heaters using more electric than advertised? I had noticed recently our overnight phantom energy use seem to be a bit more than expected so the last 3 days i have just tested 3 different heaters using an energy monitor plug on each one and my results are as follows:

300w heater using 337w
150w heater using 166w
50w heater using 61w

over the 24 hour period each was tested on there were small variations of a couple of watts but those were the averages.

 

[GaryE]

Interesting. Heaters are often shoddily made, and disposable, which is a shame given their cost.

 

[Glenn407]

Well first, if it is drawing more power it will shut off sooner. If it takes X number of BTU's/HR to maintain a certain temperature the water doesn't care how you are going about it. One has to wonder how accurate those meters are as well. Each of those numbers is about 10%. Not saying the elements are not outputting more than advertised.

 

[Archerfish]

It is really a paltry amount at about 10% over advertised wattage. Could be a couple of things but my first guess is they want to be absolutely certain that the heater will deliver at least the advertised wattage.

 

[Uberhoust]

Could be a function of the RMS voltage that is supplied to the heater. Here the voltage at my place can vary between 115 volts and 127, based on my cheap multimeter. There might also be some line loss on the cable, they will typically target only the minimum gauge wire required for the plug in cable.

 

[davros]

Probably a bit of "cheating a the edges" where they are mfd. Use 10% less heater coil you get 10% more product but in turn draw 10% more power. The local line voltage will have an effect also.