So if you have an 18′ long room x 12′ wide room multiply times 1.5 = 324 watts, that’s how much wattage is needed to adequately light the room. You can divide that lighting into more than one source. 2 Lamps @ 150 watts each and 1 lamp @ 60 watt would be more than adequate light for the room.

Yes you can, the light output will be 33% less but then you will use less energy. light fittings should be labelled to state the maximum safe wattage bulb which can be fitted. Never under any circumstances exceed the maximum but lower is fine.

40-watt bulb produces 450 lumens of light. 60-watt bulb produces 800 lumens of light (most widely used in households)

As your build your layers of light, remember that bedroom lighting should create a peaceful, relaxing atmosphere using soft, flattering ambient light while providing bright spots in the places where they are needed. When developing your bedroom lighting design, first consider the size and ceiling height of your room.

Wattage: Multiply the area in feet by 10. For a room 20 feet by 20 feet, we obtain 400 sq. ft., multiplied by 10 to give 4000 watts. The number of watts = area x 10.

For example, you’re looking at putting downlight in your bedroom which is 4 x 5 m (20m2), you should have 180 (lux) x 20 (m2) = 3,600 Lumens in your space which is around 4 x downlights….How Many Lights Do I Need Per Room?

A general rule of thumb for spacing your downlights is to take the height of your ceiling and divide by 2. For example, if your ceiling is 8 feet high, then your downlights should be around 4 feet apart from each other. It is important to consider that this is only a very general rule and should be used with caution.

Never put a downlight over the top of the bed – you’re guaranteed a face full of glare regardless of how far you dim it. If you want downlights, position them around the edge of the room over your draws and dressers so you can see the contents. Control is essential here.

Compare lumens to watts