Aesthetically, lighting fixtures can be like jewelry for an interior, adding a bit of sparkle and just the right finishing touch to a space. Functionally, there is a lot more to selecting a fixture than just its dashing good looks. The right (or wrong) lighting selection will make or break a design, regardless of how well the rest of the space has been crafted. Below are five key concepts to understand when selecting the right fixture.
The UL, or Underwriters Laboratories, is an independent US company that tests and verifies consumer products to ensure their safety for the public. It is important to select a fixture that has been tested and approved by the UL, especially if it is going in a bathroom it will need to be UL listed for use in damp locations.
Lamping refers to the type of bulb (or lamp) used in a fixture. Different types of bulbs have different light outputs, require different amounts of electricity, and have varying lifespans. For example, LED lights have a much longer lifespan (as much as 10-15 years which is great for fixtures in locations that are difficult to service) and they are also a great option for saving on energy costs. Some fixtures can accommodate different types of bulbs, but others cannot. Be sure to check the specifications to see whether the fixture uses a bulb that is readily available in your local store, or whether it is something you will need to special order, as this will impact the ease of maintenance over time.
Lumens are the measurement of light output from the lamp, or bulb, as mentioned above. We are accustomed to understanding light output in relation to the watts of an incandescent bulb, but with so many other options (LED, halogen, fluorescent) a little math is needed to determine light output: The total output (lumens) you will get from a fixture is equal to the wattage of the bulb, times the lumens per watt for the bulb type. Therefore, a 60w incandescent that produces about 15 lumens per watt will give off only 900 lumens, whereas a 60w LED that produces 30 lumens per watt will give off 1800 lumens. (Hence the energy savings of switching to LED lights.)
Color Temperature refers to how visually “warm” the light output appears. It is measured on the Kelvin scale of 1,000K (warmest) up to 10,000K (coolest). This influences the “mood” you want to set. Psychologically, a room filled with “warm” light (2,000K-3,000K) gives a sense of cozy intimacy and is desirable in restaurants or living rooms. A “cool” white light (3,000K-4,500K) tends to make a space feel vibrant and bright, which works well in offices or bathrooms. Daylight falls around 4,600K-6,500K, which feels energizing and crisp and is great for task lighting.
Finally, the CRI is the Color Rendering Index, measured on a scale of 0-100. Different light bulbs (and hence the fixtures that require them) will vary when it comes to how accurately colors appear under the light. This is separate from Color Temperature, and gets very scientific very fast. To simplify the concept, what is important to note when selecting lighting for spaces where color accuracy is crucial (like a design studio, salon, or your dressing area at home) is that the higher the CRI number, the more accurately you will see color. Daylight has a CRI of about 75 and typically in a living space you will want a CRI of 70 or higher.
As you can tell, the art and science of lighting can be very complex, and we haven’t even touched issues like beam spread or control systems. For large projects or public buildings where lighting plays a critical role it is often desirable to engage a lighting consultant. However, understanding these five key concepts is a great starting point for discussing the basics with your architect or designer, or shopping for fixtures on your own.