If you're talking about an incandescent light, then yes, you can replace it with a 40 Watts lamp, a 15 Watts lamp, or, if you're old like me, even a 120 Watts lamp. you'll notice a few things if you go from a 60 Watts incandescent to a 40 Watts incandescent.

When it comes to the amount of light that is obtained from an ampoule, the watts do not matter. The light is not measured in watts. It is measured in walking candles or lumens. This means that this ampoule produces approximately the same lumens as a standard 60 watt incandescent bulb.

LED lamps that provide 800 lm are considered to have a luminous power equal to the standard 60W lamps. If the device is qualified to accept 60 Watt, you can safely use 75W, 100W, or even 125W equal lamps (which all generate less than 50 Watt of power).

One kilowatt-hour is 1000 watts used for an hour. For example, a 100-watt bulb operating for 10 hours would use a kilowatt-hour. Here are some examples of devices found in most homes. These examples use an index of 10 cents per kWh.

Watts matters when it comes to paying the electric bill. That's because a watt is an energy unit. Watts also matters when you choose a lamp to use on a device that has a maximum power limit or when you replace one of the lamps in a multibulb chain, like Christmas tree lights.