Humidifiers and Dehumidifiers - Several dehumidifier questions

I have an 11 year old Whirlpool dehumidifier which runs in the basement during warm months when the A/C is off (which is most of the time). I started it up about a month ago and my electricity usage was over 300kwh higher this month than last. Plugged in my Kill-a-watt and it is pulling about 7.5 amps (label says 6.8). Even though I set the control so that it just comes on, it runs almost continuously.

Questions: 1) does the fact that it's drawing more current than specified indicate a problem (I have vacuumed the coils),
2) will a new model be more energy efficient?
3) the manual says don't use an extension cord. I have it plugged into a 13 amp cord so I assume that's not going to be a problem. Is that a safe assumtion?

I could be wrong..but the extension cord could be the reason you are pulling more amps. If its long enough, you can have a voltage drop, so the unit has to pull more amps to compensate.

Extension cord rules are "for temporary use only". That said, I doubt you would have a hazard, but does the plug or cord get warm, even a little bit?

I could be wrong..but the extension cord could be the reason you are pulling more amps.

I can check but it's only a 6' cord. Haven't felt it to see if it's warm or not. I can get the unit far enough from adjacent walls that I really don't need the extension so I will run without it in the interests of electrical compliance. ;)

A good unit will use allot less energy, and pull more RH out of the home.