Originally Posted By Paulo

To give an example, Mark Jurey's penny stove here has these stats:
Fuel Use
15 ml. (1/2 oz.) of fuel will boil 2 cups of water.
That's a pretty good standard for DIY alcohol stove efficiency. If a stove can match that, it's pretty darned efficient. If a stove takes more than that, it's less efficient.

Backpacking stove reviews and information: Adventures In Stoving