electrical calculation please

Dehumidifiers are commonly rated in "pints per day"

At only 20watts, I'd doubt if it could remove a pint in 24 hours.

How about sharing the brand and model of what you're looking at and we can give you a much better idea of what it can do and what you can expect. Without that information we're all just wasting our time guessing.

20W is 20W, basically. There is a bit of loss due to the AC to DC conversion, but probably not more than about 5% or 10% these days.

20W * 24 hrs = 480 Wh per day, or about 1/2 kWh per day. Call it 15 kWh per month, assuming it's operating constantly. Not a huge amount of electricity, though it does add up to something.

I rather doubt a 20W dehumidifier is large enough to do anything useful in a house. I kind of suspect it may be based around a thermoelectric cooler (with a fan and a few other bits), which is hardly energy efficient in terms of the energy consumed vs. the cooling it produces (and hence how much water it condenses out of the air). How many pints per day is it rated for? Of course, it's perhaps possible that I'm completely wrong on what this device is or how it works, so maybe it's indeed very energy efficient...I just have my doubts.

20W*24hrs*30 days = 14.4 Kw/mth, look up your electrical rate to determine cost. At 0.20/Kw = $2.88, for a ball park figure.

BTW If you don't have Kill A Watt then buy one and you can measure the actual usage, of course you have to have the appliance. Very useful device.

Think of it as the equivalent of running a 30 W electric lightbulb 24 hours a day. That will be a close approximation.

LeRoy

Sorry if not clear. I'm trying to figure how much power the unit would use if plugged into a/c at home. In other words, how much affect on my electric bill.

Don't plan on using it while camping

That would be 1.66 amps if thats what your asking.

20w/12.1V (50% SOC)*24hrs = 40 Ah. The typical 2 GCs will have 110Ah to 50% SOC. So it will consume 40/110 = 36% of the battery in a day. Part of that will be the conversion loss to AC.