Use LED Light

• Install CFL or LED light bulbs, if you haven’t yet. These bulbs can be four times more energy-efficient than incandescent bulbs and last for many years.
• Install a programmable thermostat so you can optimize its usage.
• Unplug unused electrical devices. 

• There’s no replacement for true natural light.
• Fluorescent lighting saps your energy and makes you less productive, without even mentioning the environmental issues.
• LED light can be a good substitute for natural light.

Incandescent light bulbs existed before Thomas Edison, and when other inventors got wind of Edison's tinkerings, they roundly sued him for patent infringement. 

So what did Edison actually do?

He discovered that a special species of bamboo had a higher resis...