Step 1:Multiply the room’s width by its depth to ascertain the square footage.
Step 2:Multiply the square footage by 1.5 (or 2.5 for task areas like Kitchens) to give the total wattage needed in the room. For example in the kitchen below 4.2mtrs (thus 190SqFt x 2.5 = 475 watts
Step 3:Divide the total wattage previously calculated by your chosen bulb wattage to work out how many fittings you need. If using LED use their equivalent wattage in these sums.
Step 4: Spacing,Recessed downlights are generally positioned 1.5 to 2 ft. away from walls with a space of 3 to 4 feet between each light.
“Using a best selling 7 watt downlight this tells me to use 19 No. (I actually can’t see how to fit them all in so I used only 16 ! )”