Thanks a lot for posting your hands-on experience.

I don't see a lid in there.... do you use a lid? If not, you should. Boiling without a lid means you loose A LOT of heat due to the increased evaporation from the hot water. Trapping that steam beneath some barrier reduces this heat loss significantly. (Lots of steam in the pot means less evaporation => less energy used to making steam, more energy used for heating and boiling)

A little piece of alufoil is as good a lid as any.