Test results (Energy consumption)
3DMark06 provides a good indication of power usage. The HP Envy 23 Touchsmart is very energy-efficient, probably because the slow AMD Radeon HD 7450 barely uses any power.
Energy usage 3DMark11
Again you can see the HP is efficient, and it's slow graphically.
Energy usage idle
When idle the 46 watt consumption is low, because unlike Lenovo it does not have a mobile processor but the more powerful Intel Core i5.
Energy usage off
Here it doesn't use anything.