First plug in other things like your tv, does it read mostly everything else close to expected?

I had thought of that and I tried it on several devices. It seems be low by 25%-35% of what the listed wattage of the item. Oh well.

Can you return it? I've heard good things about those maybe you just got a bad one.

i was hoping to buy one myself

Could be a difference between real and reactive power. Ballasts are nonlinear loads, which may affect the reading.

Try an incandescent bulb if you have one, that is purely resistive. An electric kettle would work too.

Of course, there is a tolerance for meter accuracy too, but I would expect that to be within +/- 15%.

He said he did try it on other devices

I tried it on things that should be really simple like a incandescent light bulb. It can't even get that right. For a 60W bulb it shows 50W. I definitely think I got a lemon. The error seems to get worse for higher wattages. For my DeLonghi oil-filled radiator, both the low power and mid-power switches show 750 watts! No difference LOL.

Maybe because it's the older model the manufacturer was shipping all of the duds that didn't pass QC to amazon.com to get rid of them.

Just bought a kill a watt on eBay. I'll let you know if it reads accurate