I can not tell you (yet) how much it will add as I do not have metered electric,, but I just got a Big Boss induction cooktop for 47.00 (Shipping includd) from NoMoreRack.com
I do know this.. I put my small skillet on it,, Press SEAR, and by the time I move the burger to the skillet it's hot enough (400-450 degrees) not so good with the 6 qt Dutch oven (I just bought one of those, genuine Lodge Cast Iron) But I have not tried cooking in the Dutch Oven yet (Got do do that later this week) I have used it with some smaller pans and it works well.
IF A MAGNET WILL NOT STICK TO THE PAN,, Induction cooktop will not work
One thing I like about the Lodge pre-seasonsed cast iron,, About the only thing that sticks to it is said magnet.
And a couple of real nice brand new T-Fal Professional skillets too (Magnet sticks, other T-Fals it does not). and my Basic Essentials "Chef's Pan" not nearly as good as the T-Fal's. but magnet sticks. So far that and the small lodge cast iron skillet is all i've cooked with.
Local kitchen supply closed for ever yesterday,, GOOD PRICES last weekend.
Home is where I park it!