For many homeowners, especially those with children, the kitchen is the most lived-in room in the house. It's a gathering place, a workspace, a study area, an entertainment venue and of course, a room in which to enjoy meals together. Thus, it's not uncommon for kitchen lights to be switched on for four or more hours per day. This presents a legitimate opportunity to save money and reduce air pollution and landfill waste by switching to energy-efficient lighting solutions.
As a source of both ambient and task light, recessed downlights ("cans") are widely used in American kitchens. These fixtures push light down and away to light an area and a work surface at the same time. To enable the homeowner to add ambience, they're often controlled by a dimmer switch.
For homeowners motivated to make a small investment to reduce their electricity use and/or carbon footprint, a simple light bulb retrofit in their existing kitchen fixtures is a smart and easy strategy. Simply remove the existing high wattage (commonly 65-90 watts) bulbs, and insert lower wattage eco-friendly lamps which yield equivalent light output (lumens). But since there are two types of lower cost energy-efficient lighting options from which to choose, which is preferable in this application?
High-Efficiency Halogen Lamps Beat Compact Fluorescent Lamps
We've looked at this question from many angles and have concluded that screw-in (self-ballasted) CFL reflector lamps, for many the obvious choice, are an inferior, energy-efficient lighting solution. Very few consumers are familiar with the new high-efficiency halogen lamps ("HEH") which have hit the market in the last few years. The best of these models already exceed the energy efficiency requirements for incandescent reflector lamps scheduled to take effect in July 2012.
Here, we cite nine reasons why we believe high-efficiency halogen lamps, controlled by a pre-set dimmer switch, offer overall superior, energy-efficient lighting value to CFLs starting with the most important factor for electric light sources, whether energy efficient or not: light characteristics.
Reason 1 - Great Light:
Halogen light is legendary for being white, bright, crisp, and punchy and making colors appear vivid.
The light cast by CFL reflectors, while typically warm white, is average at best.
Reason 2 - Superior Illuminance:
"Illuminance" describes the amount of light on a horizontal surface, measured in "foot candles."
High-efficiency halogen lamps, especially those with a PAR (Parabolic Aluminized Reflector) configuration, throw concentrated light downwards measurably better than CFL reflectors.
The result? Much more artificial light where it's needed.
Reason 3 - Effortless Dimming:
No artificial light source dims better than an incandescent lamp. High-efficiency halogen lamps use improved incandescent technology and don't require special dimmer switches.
Dimmable CFLs cost more than non-dimmable versions. But dimmable doesn't translate into impressive dimming performance.
Reason 4 - Dimming = Longer Lamp Life:
Dimming any lamp is an energy-efficient lighting strategy because it reduces electricity consumption and harmful gas emissions. There's an added green benefit when dimming high-efficiency halogen lamps: it extends the lifetime of the lamp.
For example, constant dimming by just 15% (a pre-set dimmer enables this) will triple the life of the bulb, thereby reducing landfill waste and replacement costs.
For premium high-efficiency halogen lamps, this translates into 9,000 to 12,000 hours, roughly the same as the average rated life of an Energy Star rated CFL reflector (whose projected life is static even if dimmed).
Reason 5 - Instant On:
Just like non-halogen incandescent bulbs, halogen lamps reach full brightness with the flick of a switch.
State-of-the-art CFL reflectors will start instantly but take 30 seconds to a minute's time to reach full brightness (depending on the ambient room temperature).
Reason 6 - Mercury-Free:
High-efficiency halogen lamps operate without the use of mercury.
All CFLs contain mercury which must be vaporized to create ultraviolet energy and subsequently, visible light.
Since mercury is a toxic substance, this necessitates proper recycling at the end of a CFL's life.
Further, while breakage in a recessed can is a low probability risk, an accident would cause mercury to contaminate the area below.
Reason 7 - Reliability:
High-efficiency halogen lamps don't contain any electronic components.
Unlike a screw-in CFL, which contains a precise electronic component called a ballast, neither frequent on/off switching, nor trapped heat will affect the performance or lifespan of these energy-efficient lighting solutions.
Reason 8 - Lumen Maintenance:
Lumens are the measure of the amount of light emitted by a light source. High-efficiency halogen lamps maintain their initial lumens for as long as they operate.
CFLs, using different technology, will gradually dim by about 25% over their lifetime.
Why does this matter? Studies have shown that at age 65, the eyes need three times more light to see as well as at age 20.
With CFLs in a kitchen, vision needs and light output are moving in opposite directions as time passes.
The Rest of the Story - High-Efficiency Halogen Lamps Are Greener
Reason 9 - Better, REAL Energy-Efficient Lighting:
The commonly used metric for comparing energy-efficient lighting is lumens of output per watt of electrical input. This method is appropriate for omni-directional bulbs such as traditional A-shape lamps and spiral CFLs.
Directional lamps (floodlights, spotlights) are different. Their job is not to glow, but to throw light into a defined area or onto a specific surface.
Compare the measured light (illuminance) on a horizontal surface from two floodlights, a 16 watt CFL BR30 (630 lumens) and a 34 watt HEH PAR30 (1) (612 lumens).
The CFL has 39 lumens per watt vs. 18 for the HEH. Thus, by conventional measures the CFL is more than twice as energy efficient.
Measured illuminance tells a very different story: the CFL floodlight casts just 15 foot candles of light onto the work surface in this demonstration. The HEH? 51 foot candles.(2)
Therefore, at 1.5 foot candles per watt, the HEH bulb is 60% more efficient in real terms than the CFL (0.9 foot candles per watt).
Or viewed another way, using typical recessed downlight fixtures, to produce an equivalent amount of light on a kitchen countertop or table, where important tasks such as food preparation and schoolwork are performed, a 54 watt CFL floodlight would be needed.
Not only would such a lamp be more expensive to purchase, it would cost 36% more to operate and generate 36% more air pollution than the high-efficiency halogen lamp.
Notes for Previous Example
1. A 40 watt model was dimmed by 15% to reduce lumen output from 720 to 612.
2. Measured distance of each light source to the surface of the light meter instrument was 50 inches.
Illuminating the Perks of Energy-Efficient Lighting
Impressive consumer value is sometimes found where it's least expected. We're all for selectively installing energy-efficient lighting around the home and place of business because it leverages the fact that the cheapest and cleanest kilowatt of electricity is the one that's never produced in the first place. But if light bulb buyers only paid attention to the popular media or followed Energy Star prescriptions, they would only know to consider CFL reflectors as an affordable, energy-efficient lighting solution for their oft-used recessed downlights.
As we've argued here, the exciting new high-efficiency halogen lamps (spot and floodlights), which are generally priced on par with premium quality dimmable CFL reflectors, are superior energy-efficient lighting solutions for consumers who value great light characteristics, thrift, dimming performance and environmental sustainability for their lighting dollar.
