We-Design-Day: How do you solve a problem like...

How much light do I need in my work space?

Today, I'm going to explore more about lighting design. If you remember this post, we discussed the types of lighting - today, I want to get a little more in depth about how we can use those lighting ideas and how you can employ them to creatively, aesthetically and functionally design the lighting in your home or office.

As always, first we must cover a bit of terminology (put your learning hats on)...

Lumens the unit of measure of light output - traditionally defined as one lumen equals the same amount of light put out by one candle
Wattage determines the energy used by the light*
Light output how much light a light source will generate
Colour Rendering Index a measure of how precisely an artificial light source displays colours
Colour Temperature colour temperature of a light source indicates the colour of the light put out by the source and is measured in degrees Kelvin (the lower the value, the warmer the light put out. Higher values are cooler. Incandescent bulbs are lower (more yellow) as where fluorescent bulbs (especially traditional ones) are more blue
Efficacy is the ratio of the lumens produce to wattage consumed (or used)

*We all know bulbs are sold by watt - 40, 60 or 100 watt (incandescent) and now we've got 15, 22, 32 (and many more) in fluorescent bulbs. This number does not equal light output by the bulb (or brightness of the bulb). This number - the wattage of the bulb - only specifies the amount of energy used by the bulb each and every time the light is turned on. To measure the brightness, we have to use Lumens. Additionally, looking at other factors, like temperature or colour rendering index of the brightness quality will also aid us in selecting the correct lighting for our homes.

The next step is to examine the space we are designing the lighting for and the activities that will be going on in the room. All rooms in our homes have different requirements and needs based on the function of the space. There are variables we can try to accommodate when developing our plan.

Who is using the space and how is their eyesight? As we age, our eyes require more time to see things and we require much more light to see. The type of tasks being done are also a key factor as to "how much" light will be needed.

Professionally, I have used a set standard when doing lighting designs and similar principles and guidelines should be employed. When we look at lighting as a whole, standardized light levels can be (and have been) employed. Naturally because every situation is different, the levels can be adjusted to meet the needs of the space, client and design.

Here are some averages to give you an idea:
Space Recommended Light Output (lumens/square meter)
Kitchen 300 - 550
Living room 300 - 500
Home office/workshop 500 - 1200
Dining Room 200 - 350

During my research, I happened upon a gem of a resource. It is a simple and effective planning guide for lighting! Provided for free download from our friends at the Office for Energy Efficiency with in the Department of Natural Resources Canada, is the Home Lighting Design Guide Pocketbook

I'm going to wrap it up here for this week - there is a lot of information to digest and because its a big subject, it is important to take the time to sit back and think through the space you are going to be illuminating.

References:
Natural Resources Canada
Home Depot Canada
TCP
BC Building Info
MegaVolt
Image courtesy of Outdoor Wedding Lighting