Sous-vide and electricity consumption
My father and sister always complain that I’m using too much electricity when sous-vide cooking a piece of food. They get scared by high numbers, namely the 1000-watt heater that I use. You can’t blame them though, considering how lightbulbs in our house operate on a measly ten watts.
Of course, when you analyze the sous-vide system, you begin to realize that the transfer of energy is very much efficient. Unlike cooking foods on a stove where the flame loses energy to the surrounding atmosphere, constant temperature water baths allow energy to transfer directly from the heater, by conduction, to the water. The only loss in energy comes from the heated water itself evaporating or losing heating to the surrounding atmosphere. However, because air is a horrible conductor of heat, such energy loss becomes minimized—even more so if you insulate your water bath than not. Consequently, maintenance of a desired temperature consumes very little energy, oftentimes not much more energy than it takes to initially heat up the water bath.
A little experiment done by a fellow sous-vide cooking blogger proves that the method is not as expensive as my dad and sister originally thought. Further research supports the blogger’s findings. Sure, you could argue that the above findings were procured by advocates and users of sous-vide cooking, but it’s hard to argue with numbers derived from a simple experiment with little room for error or variability.