Efficient & Effective Kitchen Lighting

There's a critical missing element in most American kitchens, and it's not a $10,000 range or a stainless steel French door refrigerator.

It's good lighting.

Most kitchens not only do not have enough lighting, they have the wrong kind of lighting.

Your kitchen is more than just a place to cook and eat. It usually serves as the administrative and social hub of the home.

Because it typically opens for business before dawn and closes long after sunset, a kitchen uses a lot of energy for lighting. That makes this room an important place to use efficient lighting.

While remodeling your kitchen, you have the perfect opportunity to create an effective but also highly efficient lighting system.

Designing a lighting system that provides just the right light yet uses very little electricity is the goal of lighting design. It is not a trivial process. And it requires an intimate understanding of how light works.

More Than You Ever Wanted To Know About Lighting

If you have ever watched a welder at work, you know that arc welding produces an amazingly bright light – so bright that special eye protection is required. This was the first electric lamp: the carbon arc lamp.

The 1860 Republican convention that nominated Abraham Lincoln for president was held in a large wooden building in Chicago lit by carbon arc lamps. The fact that it did not burn down, eliminating the newly formed Republican Party, is a testament to careful and constant vigilance. Temperamental, dangerous, expensive, and requiring constant adjustment, these lamps were not practical for everyday use.

A few years later an English chemist, Sir Jo­seph Wil­son Swan, D.Sc.h.c., FRS (and not Tho­mas Edi­son as you were taught in school), developed the practical in­can­des­cent lamp, the first relatively safe source of electric lighting.

There have been huge improvements in lighting since the 19th century, but almost all the lamps we use are still of the two types: in­can­des­cent and electrical discharge (the new name for arc lamps).

The only new kind of lamp developed in the past 100 years is the light-emitting diode (LED) which works on an entirely different principle.

How Electricity is Converted to Light

Light is composed of photons – very small particles that our eye can see. Photons move very quickly. In fact, they travel at, ahem, the speed of light. They also vibrate. The rate of vibration, or frequency, determines the type and color of the light they produce.

We can see only a small portion of the total light spectrum. This is "visible light." The rest of the spectrum including infrared and ultraviolet, is invisible to us, although other animals can see this light very well, which is why they seem to see in the dark. It's actually not dark to them.

Converting electricity into light requires adding energy to an atom until one of its electrons jumps to a higher orbit. It then starts losing energy. When it loses enough energy, it drops back down to its former orbit and, in the process, shoots out a photon. Then the process repeats itself.

It all happens very fast and to a lot of atoms at the same time. The entire cycle of electron movement to a higher orbit and back down takes just a tiny fraction of a second.

The result is the steady flow of photons that we see as a stream of light. Some materials do better at producing light than others. In in­can­des­cent lamps, the material most commonly used is tungsten.

Incandescent Lamps

An in­can­des­cent lamp produces light by heating a thin tungsten wire to a very high temperature (2200^°C), causing it to incandesce or glow.

The wire is called a filament. The incandescence results from the filament's resistance to the flow of electrical current.

Most of the energy produced is in the form of heat. Only a small fraction results in light.

The enclosure or glass envelope around the filament is called the bulb and serves two primary functions.

• It keeps oxygen away from the filament. When the filament is exposed to oxygen, it quickly "oxidizes" and breaks within seconds.

• It maintains a constant environment for the filament to retard the evaporation of tungsten. The bulb is usually filled with an inert gas such as argon and nitrogen. Halogen and xenon (pronounced z-non, not x-non) lamps are merely varieties of in­can­des­cent lamps filled with different gas mixtures.

The light eventually "burns out" when a point is reached at which the filament does not have enough tungsten to incandesce.

For the standard A-Series in­can­des­cent lamp, that time is about 1,000 hours of steady use (flipping the light on and off – as we do in the real world – reduces that time to a few hundred hours).

Understanding Light Quality

Light quality has two parts: "color temperature" and "color rendering."

Color Temperature

The more obvious of the two is color temperature: whether the light appears 'warm' (yellow) or 'cool' (blue).

Color temperature is usually stated in Kelvins (K) in the U.S. and Canada.

An in­can­des­cent lamp is about 3000K (yellow/warm). Sunlight is about 5000K (blue/cool).

Fluo­res­cent lamps come in these and other color temperatures. Which one you choose is subjective – like picking paint colors.

Today, the most used color temperature is 3500K, not too cool, not too warm. This color is often preferred for retail, office, and high activity residential spaces.

Nat­ur­al "daylight" (5,000K) lamps are the preference for baths and dressing rooms.

Color Rendering

The other part of light quality is color rendering: the ability of a light source to reveal the "true" color of an object. Its true color is the color of the object as it appears at under the noonday sun.

Light sources with poor color rendering cloud the difference between similar colors.

For example, a slate green wall may appear to be the same color as a gray-blue wall, or dark amber paint may look the same as light brick red.

Fair 50-70 CRI
Better 70-80 CRI
Best 80-90 CRI
Image Credit: Energy Star

Color rendering is expressed as a number on the Color Rendering Index (CRI), a scale from 0 to 100. Higher values are better.

Most old-style fluo­res­cent lamps had poor color rendering (50 - 40) which is not flattering to either colors or people (dull colors and gray complexions).

The newer fluo­res­cents have a very good CRI (from around 75 up to as high as the 90s), which reveal true colors more accurately.

The minimum CRI rating for any lamp is 80.

How to Determine Light Quality

Manufacturers are not required to disclose either the color temperature or color rendering of their lamps. Most do not, and such terms as "daylight" or "natural light" do not necessarily indicate a specific color temperature.

Sylvania's daylight bulbs, for example, have a temperature of 3500K, while other "daylight" lamps range up to 5000K.

However, any lamp rated as an Energy Star product now has to disclose its color temperature.

The Energy Star is awarded to only fluo­res­cent bulbs that meet strict efficiency, quality, and lifetime criteria.

Energy Star qualified fluo­res­cent lighting uses 75% less energy and lasts up to ten times longer than normal in­can­des­cent lights.

The small increase in the initial cost of these lamps is more than offset by their increased efficiency and longevity. In terms of life-cycle costs, they are a true bargain and should be your first choice in luo­res­cents.

Some manufacturers now label their CFLs with a 3 digit "light quality" code to indicate the color rendering and color temperature of the lamp.

The first digit represents the rounded off CRI, while the second two digits indicate the color temperature.

For example, a CFL with a CRI of 83 and a color temperature of 2,700 K would be given a light quality code of 827 – a warm light that has good color rendering.

Adapted from "I Hate Fluo­res­cent" by Eric Strandberg, LC, Lighting Design Laboratory, Seattle City Light

Incandescent lamps are known for their warm color – they emit more low-fre­quen­cy red and orange light than high-fre­quen­cy blue and violet.

Cheaper than any other lighting option to purchase, in­can­des­cent lamps are far more expensive than every other lighting option to burn.

Because they consume so much electricity in­can­des­cents are banned in the U.S. and have been since January 1, 2014.

The Ener­gy In­de­pen­dence and Se­cur­ity Act of 2007 allows only some special-use in­can­des­cent bulbs to be sold – bulbs that cannot be easily replaced with more efficient lighting technologies.

Some examples are small bulbs like appliance bulbs and Christmas tree lamps, some colored bulbs, hard-use lamps, bug lamps, and infrared heat lamps.

With these few exceptions, the standard household A-Series in­can­des­cent bulb is history in this country and most of the rest of the world.

Fluorescent Lamps

The tubular fluo­res­cent lamp is the household version of the electrical discharge or arc lamp. The technology has come a long way since the Re­pub­li­can Na­tion­al Con­ven­tion in 1860.

The lamps are now very safe and very efficient. In fact, fluo­res­cent tubes are up to 20 times more efficient than in­can­des­cent lamps. Com­pact fluo­res­cents or CFLs with a screw base intended to replace in­can­des­centt bulbs can be 2-10 times more efficient, although 2-5 is more common in household models.

Some 35-watt CFLs have the same light output as 150-watt in­can­des­cents.

A fluorescent lamp is a more complicated device than an in­can­des­cent lamp.

Essentially, it is an arc lamp inside a glass tube. Electrical current jumps from one electrode to the other through a mixture of argon gas that contains a tiny spec of mercury. The arc vaporizes the atoms in the mercury, forcing it to emit photons.

These photons, however, are in the ultraviolet range. We cannot see them. So, a final step is needed to convert them into visible light.

The ultraviolet photons strike a phosphorus coating applied to the inside of the glass tube. The phosphorus absorbs the ultraviolet photons and releases photons in the visible spectrum that we can see.

This is the " fluo­res­cence" in fluo­res­cent bulbs. The composition of the phosphorus determines the color or quality of the light.

Fluorescent lamps need a "ballast" to provide the proper electrical input.

Unlike the in­can­des­cent bulb, the electrical input to a fluo­res­cent bulb cannot be constant.

Electrons at rest prefer to stay that way. They need a strong jolt of electricity to get them moving enough to arc. But once moving, they require very little electricity to keep them moving.

So, the ballast has to produce an initial jolt to get the process started, then cut back slowly as the conductivity inside the bulb increases.

The current they apply is also not constant. They work in pulses, sending current for a brief while, then turning it off, then back on, and so on.

The old electro-magnetic ballasts operated at 60 cycles per second – meaning that the lamp turned off and back on 60 times each second.

Some people could see the resulting "flickering" and hear the high-pitched hum. A few people got headaches and nausea from it.

The new electronic ballasts are a tremendous improvement. They operate at 24,000 CPS or higher and use less energy. There is no discernible flicker and no hum.

But, there is a problem with CFLs used in ceiling fixtures. Installed with the ballast at the top, "ballast-up", they do not last very long.

Many contractors are experiencing the problem. No one knows why, although there are several theories. Ballast-up CFLs still outlast in­can­des­cent bulbs, but only by a factor of 2x or so.

Manufacturers are aware of the issue and are working on it. But, for now, don't expect the ceiling-mounted CFLs to last as long as the bulb in your desk lamp, installed ballast-down.

If you are buying new ceiling fixtures, get the ones designed for CFLs that mount the bulb in the side rather than at the top of the fixture. Better yet, use LED bulbs.

Fluo­res­cent lamps do not abruptly "burn out" like in­can­des­cents. Over time they merely get dimmer, eventually losing as much as 30% of their light. Most people don't notice the change.

What eventually fails in most fluo­res­cents is the ballast. Once this is gone, the light simply will not work and requires replacement.

The unattractive "blue-ish" light once associated with fluo­res­cent lamps is pretty much a thing of the past (See Sidebar).

"Daylight" or "natural" light fluo­res­cents emit more light in the red-yellow range, emulating the warm look of familiar in­can­des­cent light. For most uses, a light somewhere between warm in­can­des­cent and cool fluo­res­cent is about right.

Halogen/Xenon Lamps

A Halogen lamp is not a different kind of lamp, it is merely another form of in­can­des­cent lamp.

It has a tungsten filament just like a regular in­can­des­cent, but because the lamp operates at a very high temperature, the bulb is more durable quartz instead of glass.

Instead of containing argon and nitrogen like a regular in­can­des­cent lamp, the bulb is typically filled with argon and a trace amount of bromine or iodine vapor.

Bromine and iodine are elements from the halogen group of elements; – hence "quartz-halogen."

As is the case with a regular in­can­des­cent, the tungsten evaporates slowly whenever the lamp is in use, eventually depleting the tungsten to the point where it will no longer emit light.

But the argon-halogen gas in a halogen lamp carries the evaporated tungsten particles back to the filament and re-deposits them. This gives the lamp a longer life than regular A-Series in­can­des­cent lamps and ensures a cleaner bulb wall for light to shine through.

Halogen lamps are slightly more efficient than regular in­can­des­cent lamps, but not greatly so. Their real advantage is in their longer rated life before burn-out, not in their efficiency.

The newest incarnation of the quartz lamp for household use is the xenon lamp. The hype surrounding Xenon bulbs suggests that they are a radical innovation in lighting technology. In fact, they are merely a halogen lamp filled with xenon rather than argon gas.

Developed originally for automobile headlights, The bulb has migrated into household low-voltage systems. Its advantages are that it burns slightly cooler and produces a more even "whiter" light than regular halogen lamps.

Halogens last between 2,000 and 3,000 hours. CFLs last 8,000 to 10,000 hours, and fluo­res­cent tubes at about 20,000 hours far out-performing halogen lamps.

Light-emitting diodes, however, outlast them all.

Light-Emitting Diodes

Unlike "innovations" such as halogen and xenon bulbs, light-emitting diodes (LEDs) are truly something new.

Although invented in 1962 by Nick Holonyak, Jr., LEDs did not become commercially practical as a replacement for in­can­des­cent and fluo­res­cent lamps until 1995 when Jürgen Schneider, a German physicist, developed an LED that produced a full-spectrum white light in contrast to earlier "white" LEDs which were blends of red, green, and blue light.

LEDs don't have filaments to burn out. Instead, they produce light from one of the simplest electronic semiconductors: a diode.

A diode is a semiconductor composed of two different materials bonded together. Electrons flow from one material to the other, producing a current. This current results in the release of photons.

All semiconducting materials produce photons, but in most semiconductors, the electron jump is so short that the photon produced is in the ultra-violet range, a higher frequency than we can see.

Special materials, usually modified aluminum-gallium-arsenide (AlGaAs), are used for LEDs because they force the electrons to jump a larger gap, producing photons in the visible spectrum. The gap can be tuned to produce different frequencies and, thus, different colors of visible light.

But this is not yet all of the story.

In an ordinary diode, the semiconductor material itself absorbs much of the light produced. LEDs are specially constructed to release a large number of photons outward and are housed in a bulb that directs most of the light out of the tip of the bulb.

You can see this directional effect in traffic signals that use LEDs. From head on the light is bright and clear. As you move to the side, however, the light becomes dimmer until at some point it cannot be seen at all.

Did Edison Invent the Light Bulb?

Almost certainly not.

Sir Joseph Swan, a British inventor, first patented a workable in­can­des­cent light bulb in Britain 10 years before Edison's patent.

Joseph Swan

Swan published his work in Scientific American where Edison presumably read about it.

Swan sued Edison in English courts for patent infringement and won. Edison was forced to give Swan a substantial interest in Edison's British electricity venture, renamed Edison and Swan United Electric Company, colloquially known as "Ediswan" Electric.

On this side of the Atlantic, Edison fared no better. The U.S. Patent Office invalidated Edison's patent, ruling in 1883 that Edison had based his patent on the earlier work of William E. Sawyer who founded the Electro-Dynamic Light Company with Albon Man to produce electric lamps.

The company later became the lighting division of Westinghouse Corporation.

While some give Edison credit for inventing a practical filament that could be mass-produced inexpensively, in fact, a cellulose filament, also aSwan Invention had been manufactured for years before Edison stumbled upon the tungsten filament.

Because LED bulbs are clusters of diodes, they can be made "smart". Smart bulbs are in­ter­net-cap­a­ble. They allow lighting to be customized, scheduled, and controlled remotely using a smart­phone.

They can be programmed to change brightness or color temperature to fit a particular mood or time of day. Bright, cool light that's closer to blue has an energizing effect and is best for the morning wake-up. Softer, warm light is more relaxing and is best after the sun has gone down.

Some smart bulbs can change from visible light to infrared to help your home security cameras see in the dark. Others have built-in movement sensors and cameras to detect intrusion. Some include speakers to enhance your surround-sound experience.

The service life of LEDs is somewhat difficult to measure since it, more than for any other lighting technology depends on environmental factors and design.

Manufacturers have begun rating their LEDs at about 70,000 hours – or 3 1/2 times the lifespan of a fluo­res­cent tube. About 10 years of normal use. But again, this estimate may be difficult to interpret.

An LED "bulb" is a cluster of dozens to hundreds, even thousands, of individual LEDs. Some of these can "burn out" without much decrease in overall lighting. Even the term "burnout" is not accurate in describing an LED. LEDs slowly decrease in light output but rarely reach zero light.

At present, the Illuminating Engineering Society (IES) recommends considering an LED "burnt out" when it reaches 30% of its original light output.

The price of semiconductor devices has plummeted over the past decade, making LEDs a more cost-effective lighting option for a wider range of lighting applications. The development of a replacement for the standard A type in­can­des­cent bulb – what we think of as the standard lightbulb – with an E26 Edison screw base that fits a standard light socket has skyrocketed their popularity.

Efficient Lighting Requires Precise Design

Efficient lighting starts with good design. The design principles are fairly obvious:

• Use the most efficient lamp appropriate for the application.
• Plan circuits so that unnecessary lights may be turned off without affecting necessary light.

• Make lights easy to control so it is convenient to turn off lights no longer needed.
• Layer lighting for maximum impact. Ambient lighting provides general room illumination. Task lighting helps homeowners see better where they need it – undercabinet lighting in the kitchen to help in preparing meals, for example. Accent lighting adds sparkle by focusing on an architectural detail such as a display cabinet or on photos or artwork.

Task Lighting

A task area is any place in a kitchen where work is done. The cleanup area around the sink, the cooking area surrounding the range, and the countertop where food is prepared are all task areas.

Task areas are best lit with bright (but not glaring), shadowless light from two or more light sources.

This is usually done with a combination of general room lighting combined with focused undercabinet lighting.

Until a few years ago, fluo­res­cent tubes were our first choice for under-cabinet lighting because of their high lumens per watt. We typically recommended flat T5 or T8 fluo­res­cent lamps with electronic ballasts. These lamps are hidden under the wall cabinets they are attached to, so they don't have to be pretty (which is a good thing, because they're not).

Today we are more likely to use low-voltage strip LEDs.

The illumination they produce is even more uniform, and efficiency is high – 60 lumens per watt is average or about four times the efficiency of an in­can­des­cent bulb.

The individual LED bulbs are tiny and easy to conceal. The strips last a long time. Around six years is average, but we installed some strips 12 years ago that are still burning brightly. And the operating cost is very low. In a typical kitchen, figure about $7.00 annually.

If you already have T5 and T8 fluo­res­cent undercabinet fixtures, you can buy LED replacements that take LED tube bulbs. These are usually called LED-ready fixtures. The bulbs look like the fluo­res­cent tubes they replace but do not need a ballast.

The underside of the wall cabinets is where most designers put task lights.

Where there are no upper cabinets, two choices are available: projecting light from a ceiling-mounted fixture or using pendant lamps that hang on long cords from the ceiling. Island lighting and lighting over the sink are often done this way.

The key is to use soft, shadowless light and to direct the light so your body does not cast a shadow on the work area.

Making sure there is enough light is also critical. Lighting experts use special meters to measure the amount of light falling on the work surface and from this information have produced tables that tell us how much light we need to provide in each situation.

We generally use a tried and true rule of thumb. Multiply area to be lit (in square feet) by 24 to calculate the lumen requirement for general room lighting, and by 40 for task lighting. Then it is merely a matter of adding enough light to reach the desired lumen level.

Since CFLs and LEDs produce little or no heat, they are especially suitable for recessed fixtures. in­can­des­cent lamps produced so much heat that special recessed fixtures were needed for contact with insulation in the ceiling to prevent fires. CFLs and LEDs don't create much heat but most electrical codes have not caught up yet, so these special fixtures still may be required.

General Room Lighting

General room lighting or "ambient lighting" is the overall light that fills in shadows, reduces contrast, and lights vertical surfaces to give the space a brighter feel. Used cleverly, it can even trick the eye into believing the kitchen is more spacious than it really is. (See Getting More Kitchen Space for more details.)

This background light is what you need for casual activities in the kitchen.

If the kitchen has lots of windows you should have plenty of natural ambient light during the day. But, kitchens are used from before dawn until after midnight – we can't rely on windows and skylights alone to provide adequate room lighting.

Fluorescent tubes are well suited to the task of providing general room illumination or "ambient" light. They provide broad, even lighting, and their efficiency makes it possible to fill the space with light without turning it into an oven in the Summer. LEDs tubes are even better. They cost more to purchase but pay back the extra cost well within their ten-year lifespan.

You can put the tubes in a central fixture, but you may want to try some other approaches.

One that we like a lot and use often is placing them on top of the upper cabinets to reflect light off the ceiling. This technique is called "cove lighting". If you have at least 12 inches of space from the top of the upper cabinets to the ceiling, this is an inexpensive way to brighten up a kitchen.

It works best, however, if the kitchen cabinets are modified slightly for cove lighting, including placing a reflective surface on the top of the cabinet.

You can buy the cheapest fixtures that work – they will never be seen. A fluorescent tube fixture so ugly that you wouldn't install it in your garage is perfect for cove lighting and costs about $15.00.

Accent Lighting

Use accent lighting to focus the eye on key features of the kitchen. This lighting gives your room a sense of depth and dimension, adding to the quality of the space.

Use it sparingly, however, just to emphasize those special home objects you want people to notice and admire.

You may be lighting artwork, architectural details, collectibles, or a food presentation area. Lights in glass-front cabinets used to store fine china, or lights in display alcoves are examples of accent lighting. To be effective, accent lighting should be 3-5 times brighter than the surrounding ambient light.

Night Lights

Kitchens and baths should have a low-voltage standing light – a light that is constantly on at night or turns on when movement is detected. In most kitchens, the standing light is the fixture over the sink. A more appealing option is a string of perimeter toe-kick lights.

The toe-kick is that recess under the front of the cabinet where your feet go when you are working at the cabinet. Low-voltage linear lighting systems installed inside the toe-kick "float" the cabinets in a pool of light.

The design effect is dramatic, and because the perimeters of the kitchen are outlined in light, it is easy to find your way around without stubbing a toe. Toe-kick lights are typically rope lights (LED pea bulbs linked together) often controlled by a motion sensor that turns the lights on when someone enters the room – but only at night.

Like all electronic devices, the price of this sophisticated switching has plummeted in recent years, making it an affordable option for most homeowners.

Wireless Switches

Good lighting design requires good lighting control. Lighting controls allow you to put the right amount of light in the right places and turn off unneeded lights without affecting the lighting actually in use.

Today there are central electronic control panels that allow you to switch lights on and off throughout the house based on the time of day, the amount of sunlight, and how the rooms are being used at the moment.

For most of us, this is a little too much switch, but they are available.

Lighting control is now easier than ever with wireless switches.

Wireless switches use technology similar to garage door openers. The switch sends a radio signal up to 50 feet to tell a specific light to turn off or on. Wireless central controls can be used in place of wired switches to handle all of the switches in a house – lights, fans, appliances, and security.

In an age when copper wire is quickly becoming a rare metal, wireless operation is becoming a more cost-effective option – especially in remodels.

Wireless switches can save money in remodeling because they require no wires, no demolition, no patching, and no re-painting, all of which can run several thousand dollars.

Most remote switches are powered by batteries that need to be replaced periodiclly but some make their own electricity using a micro-generator that creates a tiny burst of electricity each time the switch is thrown. The electricity is enough to power the transmitter that signals the light to turn on or off. We have heard these called "kinetic" switches, although we are not sure it is an industry-wide term.

The only problem with energy harvesting switches, apart from their higher cost, is that throwing the switch does not feel normal, which disconcerts some people until they get used to the absence of the expected "click".

Dimmer switches reduce light output and energy use. Older CFLs and LEDs did not dim, but there are now fixtures for use in dimming circuits. They are more expensive than standard fixtures, but they are available.

Simple on/off switches can help save energy if fixtures are divided into separately switched task areas. For example, the counter, island, range, and sink should each have a separate switch.

Behind the Scenes: The Hidden Kitchen

Lighting is not, of course, the only structural issue in designing a remodeled kitchen. Putting together a kitchen is not a trivial process. Besides the obvious considerations: new cabinets, appliances, a new floor, and paint or wallpaper, there are many hidden considerations.

The hidden structure is invisible, and usually not very pretty, but very important. Without adequate electricity, lighting, plumbing, heating and venting – all the new cabinets and … (Continues)

Rev. 08/28/22