Cookers, heaters and other appliances

Cookers lose heat to the air, which lowers their efficiency.

Old coil cookers

The least efficient.

The immersion heater

The most efficient way to heat water: all the heat from its element goes into the water.

Hot-plate cookers

More efficient, because less heat is lost — rice cookers, for example.

Microwave ovens

Very efficient, because the heat is made inside the food, though not suited to every kind of cooking.

Induction cookers

Now on the market and more efficient still: a changing magnetic field heats only the base of the pan.

Fans

A table fan cools a room more efficiently than a ceiling fan.

Televisions

Televisions with an LCD screen use less energy than old ones with a cathode ray tube (CRT). Sets whose LCD screen is lit by LEDs use very little power and are sold as LED televisions.