Two hours after I made hot water using this the water is still hot while the carafe is cool to the touch.  

It seems like this would use less energy than regular coffeemakers as it shuts off when it finishes making coffee and there is no hot plate under the carafe.  I heard that it is more efficient to reheat your drink in a microwave rather than leaving your coffee maker on, but this is even better. 

There is no way to tell how much water is left in the carafe.  You must hold a tab down in order to pour - wish this part seemed sturdier. 

It takes the basket type of filter.  It does not come with any filters so make sure you have a filter on hand. 

I received a free sample in exchange for my honest evaluation