According to lighting research center there are different aperture sizes available for recessed light ranging for 3 inches to 7 inches and above. With all the multiple sizes available for recessed lights, it is important to know exactly what size recessed light is required for a particular place.
Calculator to size recessed lights for any ceiling height.
Rule to determine the size of recessed light based on ceiling height
To size recessed lights for any ceiling height, A good rule of thumb is to simply divide the height of the ceiling by 2.1 . The result gives the diameter of recessed light in inches.
For example, if a room has a ceiling height of 9 feet. Then according to formula, the correct size of recessed light of that ceiling would be 9/2.1 = 4 inches
If the value after decimal point is less than 5 than the value before decimal is the size the size of recessed lights and if the value after decimal is greater than 5 then the add 1 to the digit before decimal to get the final size of recessed light for any ceiling height.
for example, if height of ceiling (in ft)/2.1 = 4.2 the final value is 4 inches and similarly if height of ceiling (in ft)/2.1 = 4.6 the final value would be 4+1 = 5 inches.
Factors on which the size of recessed light depends.
There are multiple factors on which the size of recessed lights for a particular ceiling depends upon.
1. Recommended lumens for 1sqm of the area to be illuminated
The recommended lumens for 1 sqm of the area to be illuminated is important to know as this value will decide how much bright the recessed light should be at the ceiling.
How much brightness the recessed light emits is directly related to its size as well. the bigger the size of recessed light the more brighter the recessed light is at a particular wattage.
For bedroom the recommended lumens for 1 sqm is 200, for kitchen it is 200- 300 lm per sqm for general illumination and 500 lm per sqm for task areas illumination , for living room it is 150 -200 lm per sqm, for dining area it is 150 – 200 lm per sqm.
From this, it is clear that a smaller size recessed light is ideal for illuminating the areas where lighting requirement is less whereas, areas where lighting requirement is greater, a bigger sized recessed light should be preferred.
2. Height of the ceiling
The height of the ceiling is directly proportional to the size of recessed lights. The greater is the height of the ceiling the greater is the size of recessed lights.
This is because, light follows an inverse square law according to which when the light is placed at some distance from the object, the intensity of light received by the object will get reduced which is equal to 1/d2 (d is the distance of object from the light source.)
Therefore for smaller height ceilings, small size recessed lights should be used and for higher ceilings, bigger size recessed lights should be used.
3. Aesthetic appeal
For ceiling of a particular height, the aesthetic appeal of recessed lights decreases as their size increases.
Meaning, that in a room with a ceiling of 8 ft height. a 3 inch recessed light would look the most pleasant and as the size of recessed light is increases from 3 inches to 6 inches and above, this aesthetic appeal of will decrease.
Sizing recessed light for 8 ft ceiling
Recessed lights size for bedroom with 8 ft ceiling
For a standard size bedroom with 8 ft ceiling the ideal size of recessed light is 4 inches. Placing 4 inches recessed light close to the walls will not only provide sufficient brightness but will also help to brighten the walls which is important to create a mood ambience in bedroom.
Recessed lights size for kitchen with 8 ft ceiling
For a standard size kitchen with 8 ft ceiling, 4 inch recessed lights should be preferred. The reason is that 4 inch recessed lights have a greater aesthetic value compared to bigger size recessed lights also compared to 3 inch recessed lights, 4 inch recessed lights are more energy efficient.
Recessed lights size for living room with 8 ft ceiling
For living room with 8 ft ceiling, the correct size of recessed lights is 4 inches.
Living room is a place where the ambience should be cozy. 4 inch recessed lights placed carefully on ceiling close to the walls helps to achieve contrasting lighting which will have an intermix of light and shadows.
This contrasting lighting is important to create a relaxing ambience.
Other factor to choose 4 inch recessed light is the lighting requirement and aesthetic appeal. In terms of lumen output a 4 inch recessed light will always outperform a 3 inc recessed light.
Also the bigger size recessed lights are more efficient and brighter at a particular wattage, however when the size of recessed lights increases their aesthetic appeal also decreases.
Therefore, for an 8 ft ceiling living room, recessed lights of 4 inches is the ideal size.
Recessed lights size for dining area with 8 ft ceiling
A dining area with 8 ft ceiling needs recessed lights to be 4 inches in size. Just like living room, dining area also look great with contrasting lighting. 4 inch recessed light when used along with a hanging light fixture helps to achieve contrasting lighting.
sizing recessed light for 9 ft ceiling
Recessed lights size for bedroom with 9 ft ceiling
By formula, a standard size bedroom with a ceiling height of 9 ft would require recessed lights of 4 inches in size.
By considering another factor like loss of brightness of recessed light from a distance of 9 feet, a 4 inch recessed light is still bright enough to provide recommended lumens of 200 lm per sqft on the floor of bedroom.
A bigger size recessed light should only be used when the lighting requirement cannot be fulfilled by the smaller size recessed light.
Recessed lights size for kitchen with 9 ft ceiling
A standard size kitchen with 9 ft ceiling, the 4 inch recessed lights with slightly greater wattage i.e 10 watts is ideal. Using 4 inch recessed lights in pairs around the task areas helps to properly illuminate it while efficiently utilizing the space.
Recessed lights size for living room with 9 ft ceiling
A living room with 9 ft ceiling requires recessed light of 4 inches. Bigger size recessed lights are not used because the lighting is not very high as the purpose of using recessed light ins living room is to create a relaxing ambience.
It is only when living room is used for other activities that needs attention, bigger recessed light can be used. For simple everyday tasks 4 inch recessed lights is excellent for living room with 9 ft ceiling.
Recessed lights size for dining area with 9 ft ceiling
For a dining room with 9 ft ceiling, 4 inch recessed light is ideal. Using 4 inches would help to illuminate specific areas while leaving some areas dark which contributes to the overall aesthetic appeal of the dining area.
A 5 inch recessed light can also be used but only when no hanging light fixture is used over dining table. But if hanging light fixture like a chandelier or pendant light is used, then 4 inch recessed light would give a symmetrical look to dining room.
sizing recessed light for 10 ft ceiling
Recessed lights size for bedroom with 10 ft ceiling
From the formula, a bedroom with 10 ft ceiling required recessed light of 5 inches in size.
Smaller size recessed lights cannot be used in this bedroom because to overcome their loss in brightness from a distance of 10 ft from the ceiling, smaller recessed lights would consume more wattage making them less energy efficient.
Also compared to 6 inch recessed light, a 5 inch recessed light has more aesthetic appeal. Therefore, a 5 inch recessed light is ideal for a bedroom with 10 ft ceiling.
Recessed lights size for kitchen with 10 ft ceiling
According to the formula, a kitchen with 10 ft ceiling, requires recessed lights of 5 inches in size.
Around the task areas 5 inch recessed lights can also be used in pairs. If task lighting is already achieved by other light sources, then for general illumination also 5 inch recessed light is ideal for kitchen with 10 ft ceiling.
Recessed lights size for living room with 10 ft ceiling
A living room with 10 ft ceiling required 5 inch recessed lights in order to create a relaxing ambience. Placement of 5 inch recessed lights on the ceiling closer to the walls helps achieving contrasting lighting from ceiling heign of 10 ft.
Recessed lights size for dining area with 10 ft ceiling
A dining area with 10 ft ceiling requires 5 inch recessed lights. As the lighting requirement of dining area with 10 ft ceiling can be efficiently met with a 5 inch recessed light.
sizing recessed light for 11 ft ceiling
Recessed lights size for bedroom with 11 ft ceiling
Just like bedroom with 10 ft ceiling, a bedroom with 11 ft ceiling also requires 5 inch recessed light but with slightly greater wattage.
The lighting requirement of bedroom with ceiling height of 10 ft and bedroom with ceiling height of 11 ft is almost similar also 5 inch recessed light would still be bright enough from a distance of 11 ft from the floor of bedroom that it provides sufficient lumens efficiently while maintaining the aesthetic appeal.
Recessed lights size for kitchen with 11 ft ceiling
For a kitchen with 11 ft ceiling, a 5 inch recessed light is ideal. A small recessed light would consume too much wattage if it were to be placed at 11 ft ceiling to illuminate the kitchen
Recessed lights size for living room with 11 ft ceiling
According to the formula, living rooms with 11ft ceiling requires recessed lights of 5 inches in size.
When compared to living room with 10 ft ceiling, these recessed lights are even though of same size, but they differ in their wattage i.e 5 inch recessed light for living room with 11 ft ceiling have higher wattage the 5 inch recessed lights of living room with 10 ft ceiling.
Recessed lights size for dining area with 11 ft ceiling
As per the formula, a dining area with 11 ft ceiling requires 5 inch recessed lights. 6 inch recessed light can also used but only when no hanging light fixture is used over the dining table.
If dining table is already illuminated by hanging light fixture 5 inch recessed light is ideal.
Sizing recessed light for 12 ft ceiling
Recessed lights size for bedroom with 12 ft ceiling
A bedroom with 12 ft ceiling is very large and its lighting requirement is also very high. Therefore, to make lighting aesthetically pleasant as well as power efficient a 6 inch recessed light is ideal for it.
Recessed lights size for kitchen with 12 ft ceiling
For a kitchen with 12 ft ceiling, a 6 inch recessed light is ideal. Using a recessed light with size less than 6 inch for a kitchen with 12 ft ceiling, would simply not be power efficient. Also the big size of recessed light is complemented by the big height of ceiling.
This is also the reason why 6 inch recessed lights are used only on high ceiling. As they look aesthetically good only on larger height ceilings.
Recessed lights size for living room with 12 ft ceiling
A living room with 12 ft high ceiling requires a bigger light source. Hence, 6 inc recessed light is ideal for it.
The big size of these lights helps to illuminate a wide area of living room. A proper placement of 6 inc recessed light on a 12 ft high ceiling can also perform well to create a contrasting lighting for the living room.
Recessed lights size for dining area with 12 ft ceiling
A dining area with 12 ft ceiling requires a recessed light of 6 inches in size. A small size recessed light would simply not be bright enough to meet the lighting requirement of dining area with 12 ft ceiling.
