What uses less power - cooking with an oven or microwave?

Question

Mum is able to cook rice in two ways - in the (electric) oven at ~350F or in the microwave (on high). It takes half as long to cook the rice in the microwave. Both forms of rice are great, so which one uses less power?

Answer 1

The microwave oven uses less power. The electric oven uses more. Microwave ovens typically use 500 watts. An electric oven's element draws about 2500 watts while the thermostat has it switched on. Microwave ovens resonate with a rotational transition of the water molecules in the food, and this resonance is why microwave ovens are so efficient, at least on moist foods. The water in them acts like a bunch of molecular antennas, soaking up the energy. Electric ovens don't use resonance; instead they rely on radiation to cook the surface and conduction to reach the inner parts of the food, and that's less efficient.

Answer 2

Baringh is right about the microwave, the microwaves make the water molecules vibrate heating the food directly. The rest of a microwave oven stays relative cold, unlike a thermal oven. Heating in a thermal oven is done by convection using the bottom element. This heats the air which then heats the inside surface of the oven and insulation. This takes more energy and some is lost to outside. You feel the heat coming off a thermal oven but very little from a microwave as less heat is wasted. When using the top element in a thermal oven this browns the top of the food by radiation.

Answer 3

In the microwave. The energy is used only to heat the rice and water. In the oven, lot of energy is wasted in heating the oven, the vessel etc.

Answer 4

Oven