Electricity

People always have misunderstanding of what factors to consider when choosing a light and become confused when facing the terminology of watts and lumens.
Actually, for decades, we have been buying light bulbs on how much energy they consume (Watts)-no matter how much light they give us (Lumens).
But the fact is, a 21 watt halogen bulb requires 21 watt electricity to produce 110 lumens. But a  LED　MR11 Bulb, on the other hand, only use 1.8W electricity to produces the same lumens.