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What are Lumens?

very warm white led bulb

Lumens give an accurate measure of perceived light output at a given distance from a light source. Unlike the antiquated Wattage system (which measures the power required to light a bulb), Lumens indicate the true brightness of a bulb regardless of the power required to light the bulb in Watts (please see table below).

How Much Light is One Lumen?

One Lumen can be described as the perceived brightness within 0.5m of a single candle burning in an otherwise unlit room. However, increasing the Lumen count to two Lumens (i.e. placing two candles side by side) does not double the brightness – an increase of four times the original brightness is required in order to appear twice as bright to the human eye. 

This means that in order to illuminate a standard living space, hallway, bedroom, etc., many hundreds of Lumens are required (please see Calculating Lumens – “How many Lumens do I need per square foot?” below for further information on the number of Lumens that should be considered adequate to light various sizes of rooms in a home). 

Calculating Lumens – “How many Lumens do I need per square foot?”

Calculating the required amount of light output in terms of Lumens per square foot ultimately comes down to preference. For example, some people may prefer much brighter living rooms compared to the preferred brightness of a hallway, and conversely some people may prefer to illuminate entrances and stairways to a greater degree compared to snug evening spaces.

Below is a general guide that can be used to calculate the number of Lumens required to light the rooms of a home relative to the square footage of the room. These calculations are based on the presumed use of the room in terms of whether the space will be used for practical tasks (such as cooking or ironing) or whether the space is more likely to be used as a relaxation area.

In order to calculate Lumens per square feet, multiply the number of Lumens stated below by the square footage of the room:

Type of Room Calculation 
Lounge Sq ft of lounge x 15
Kitchen (food prep area) Sq ft of kitchen x 75
Hallway (/porch entrance) Sq ft of hallway x 10
Bedroom Sq ft of bedroom x 15
Bathroom Sq ft of bathroom x 75

In order to further clarify the number of Lumens required per square foot in relation to the type of room, examples have been given below (based on average conditions):

How many Lumens do I need for a lounge?

Assuming a medium sized lounge of 18ft x 12 ft, the calculation would be as follows:

(18 x 12) x 15 = 3,240 Lumens are required to light a standard lounge area

Using the table below, we can see that this level of illumination can be achieved through the use of three-to-four LED bulbs with individual Lumens ratings of 1,100.

How many Lumens do I need for a kitchen?

Assuming a medium sized kitchen of 15 ft x 10 ft, the calculation would be as follows:

(15 x 10) x 75 = 11,250 Lumens are required to light an average kitchen

Using the table below, we can see that this level of illumination can be achieved through the use of roughly ten LED bulbs with individual Lumens ratings of 1,100. 

How many Lumens do I need for a hallway?

Assuming an average narrow hallway of 5 ft x 12 ft, the calculation would be as follows:

(5 x 12) x 10 = 600 Lumens are required to light an average hallway

Using the table below, we can see that this level of illumination can be achieved through the use of roughly two LED bulbs with individual Lumens ratings of 450. 

How many Lumens do I need for a bedroom?

Assuming a medium sized bedroom of 19 ft x 10 ft, the calculation would be as follows:

(19 x 10) x 15 = 2,850 Lumens are required to light a standard bedroom

Using the table below, we can see that this level of illumination can be achieved through the use of roughly three LED bulbs with individual Lumens ratings of 1,100.

How many Lumens do I need for a bathroom?

Assuming an average bathroom size of 6 ft x 8 ft, the calculation would be as follows:

(6 x 8) x 75 = 3,600 Lumens are required to light a bathroom

Using the table below, we can see that this level of illumination can be achieved through the use of three-to-four LED bulbs with individual Lumens ratings of 1,100.

Lumens Compared to Watts

Wattage describes the electrical power required to light a bulb. Following recent technological advances in terms of the modern energy saving materials now available for use in the construction of all different kinds of light bulbs, Wattage has become a poor indicator of brightness. 

For example, a single 29W halogen bulb produces the same light output as a single 6W equivalent LED bulb. Likewise, two 150W traditional incandescent bulbs produce the same light output as two 24W equivalent LED bulbs (please see table below). For this reason, the industry no longer relies on Wattage as an indicator of brightness, adopting Lumens instead. 

Bulb Type 450 Lumens 800 Lumens 1100 Lumens 1600 Lumens 2600 Lumens
LED 6W 10W 13W 18W 24W
CFL 9W 14W 19W 23W 40W
Halogen 29W 43W 53W 72W 150W
Incandescent  40W 60W 75W 100W 150W

As an at a glance reminder, here are two examples:

What are the Lumens of a 60 Watt bulb?

A traditional 60W incandescent bulb will produce around 800 Lumens. Typically, a bedroom light fitting containing three 60W incandescent bulbs would be required for sufficient lighting. This same level of luminosity is also achieved using three 10W LED bulbs – creating a total of 30W (LED) compared to 180W (incandescent).

What are the Lumens of a 100 Watt bulb?

A traditional 100W incandescent bulb will produce around 1,600 Lumens. Typically, a lounge lighting fixture containing around three 100W incandescent bulbs would be required for sufficient lighting. This same level of luminosity is also achieved using three 13W LED bulbs – creating a total of 39W (LED) compared to 300W (incandescent).

What is the Lumen Scale?

The Lumen scale shows the difference between clinical white/blue light and warm yellow/orange light. The scale, measured in Kelvin (K), runs from a ‘warm’ 1,000K (often compared to the glow of candle light) to much more clear and cold blue/white light at 10,000K (often compared to a clear midday summer sky). The scale allows for the selection of mood or practical lighting, depending on the area of the home for the bulb’s intended use.  

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