Quality Light in the Workplace
It is well documented that light affects productivity in the workplace. The key is quality light, not quantity. A high level of ambient light alone (usually from the ceiling) is seldom satisfactory. Current best practice lighting design for the workplace emphasizes the following components: (1) task lighting for optimum individual control at the workstation and (2) daylight, if available, for ambient light, supplemented by moderate levels of 3500K to 4100K color temperature, indirect T8 or T5 fluorescent lighting. For more information or questions about lighting for the workplace, please call us at 800.867.2852.
Glare, A Common Outdoor Lighting Design Flaw
With darkness coming earlier in the day it is worth thinking about the quality of light coming from your outdoor lighting. I was reminded of this recently when I arrived at a home and had trouble navigating the steps because of the intense light coming from a poorly placed landscape light. Glare is the most common problem with outdoor lighting, both for homes and commercial buildings. Glare is caused by direct view of an unshielded light source and by high contrast between light coming from a fixture and the exterior darkness. It is better to use multiple, low light level fixtures that are shielded so they produce indirect light rather than one high brightness fixture. This basic design principle applies to all outdoor entries and walkways. For situations where the fixtures are already in place, experiment with lower light output bulbs or frosted bulbs and use the one that provides just enough light for safety. The brighter bulbs may actually be more of a hazard. Call us if you need assistance selecting bulbs for particular outdoor applications.
The Power of Blue Light
Blue light, it turns out, is not the light of the "blues." In studies done over the last few years, human exposure to blue light (light with a predominant wavelength in the short end of the visible spectrum) has a stimulation effect on our circadian sleep system. Blue light helps us wake up and stay awake. In one interesting application, hospitals are starting to use red night lights in patient rooms so that when nurses need to visit in the night, the patient is not exposed to blue light (which is present in white light) and will be less likely to fully wake up.
Do Screw Base LED Replacement Bulbs Make Economic Sense?
Do screw based LED replacement bulbs make economic sense? Availability is increasing of LED bulbs in common configurations like the workhorse 40, 60, 100 watt equivalent A-lamps and PAR20, PAR30, PAR38 equivalent floods. The energy savings is significant. A 35 watt PAR20 halogen requires only 8 watts when it's an LED. The catch of course is the price: $8 vs. $80. Where it gets interesting is when the life of the bulb is factored in: 2500 hrs for the halogen, 25,000 hrs for the LED. Now the huge price difference doesn't look so bad. Still, the high first cost is a barrier. Our advice: consider screw based LED's for special applications such as hard to reach areas where bulb replacement is difficult. With a 25,000 hour life, you can install the LED bulb and forget about it for a long time. Here are the LED bulbs we offer.
Why Dimming Incandescent, Halogen and LEDs Extends Bulb Life
Dimming incandescent and halogen bulbs not only provides both an aesthetic and energy conservation benefit, it also increases the life of the bulb. Incandescent and halogen bulbs can be dimmed by lowering voltage across the bulb filament. For incandescent bulbs, a 20% reduction in voltage using a dimmer increases the life of the bulb by a factor of nearly 20. Dimming halogen bulbs also increases bulb life, but because of bulb wall temperature requirements for the halogen cycle, the impact is less. Interestingly, dimmable LEDs may also have a small increase in life if they are dimmed. Life degradation for LEDs is determined primarily by the solid state junction temperature: higher temperatures reduce life. Since dimming lowers the junction temperature, the life of the LED should be extended.
How Efficient are White LEDs?
The energy efficiency of a light bulb is measured in lumens (light output) per watt of electrical input. A typical incandescent bulb produces up to 18 lumens/watt. A halogen bulb is a little more efficient at up to 20 lumens/watt. Fluorescent and HID bulbs have ballasts consuming some of the input electricity. Including the ballast, CFLs produce up to 60 lumens/watt, while metal halide ranges from 50 to 120 lumens/watt. It may be surprising, given all the hype, that the energy efficiency of white LEDs ranges from as low as 40 to over 100 lumens/watt. A premium 12.5W LED, being marketed as a replacement for a common 60W incandescent, delivers about 65 lumens/watt. Certainly this is a significant improvement over the 18 lumen/watt, 60W incandescent but virtually no improvement compared to the 69 lumens/watt 13W CFL, also equivalent in light output to a 60W incandescent. Clearly many factors come into play when you are comparing the benefits of various bulb options.
Guidelines for Selecting LED Replacement Bulbs for the Home
Replacing household bulbs with LEDs is becoming a viable option for people as LED prices continue to drop. The more difficult decision is how to pick suitable replacements. Ideally, after you replace your current bulb with an LED bulb, you won't be able to see any difference in the quality of illumination. To get this result, the first rule is don't think "watts." Think "lumens." Look on the packaging of your last purchase of 60W or 100W standard bulbs. You should see "Lumens" or "Light Output" listed with a number like 850 or 1600. This is the number to compare to the "Lumens" for an LED bulb. Most reputable manufacturers use a standardized label called Lighting Facts that clearly calls out the lumens (see a sample label). Select LEDs with lumens within a 5% difference of your existing bulb. Next, make sure you choose an LED bulb in a "color temperature" close to 2700K (also on the Lighting Facts label). Most people like a warm appearing light in their table/floor lamps, downlights and other general lighting applications. However, if you are replacing a PAR halogen type flood or spot with an LED, the closest color temperature is 3000K. Above 3000K you will be getting more blue color in your bulb that you may find undesirable (example, many LED outdoor landscape lights that have an icy blue appearance). LED bulbs come in dimmable versions, but you will pay more and you will need to read the fine print on which model dimmers will work. Finally look for at least a 3-year warranty. Some brand name companies offer 5-year. Our best advice: for each type of bulb in your home, buy only a single replacement LED, install it and make sure you are happy with the appearance and functionality before you replace other similar bulbs.
Other than Energy Savings and Long Life, What are Additional Benefits of LEDs?
The benefits of converting from traditional light sources to LEDs usually focus on energy savings and long life. However there are several other potential benefits worth mentioning. (1) When LEDs are switched ON, they illuminate instantly and at full light output in contrast to fluorescent, HID and even incandescent bulbs. This is especially important for emergency egress and security applications. Interestingly, LED vehicle brake lights illuminate 200 milliseconds faster than incandescent. This translates into almost 20 feet of additional stopping distance at 65 mph. (2) LED performance or life expectancy is not affected by frequent or even rapid on-off cycling. By comparison, the rated life of a fluorescent bulb is shortened when it is turned on and off many times a day. (3) LEDs are more resistant than standard light bulbs to mechanical failure due to shock and vibration. While this is not an issue for household use, it might be an important advantage for industrial and some commercial applications. (4) Cold temperatures are a challenge for fluorescent bulbs. LEDs actually increase light output efficacy as operating temperatures drop, making them excellent choices for outdoor and cold storage uses. (5) LEDs produce minimal ultraviolet (UV) and infrared (IR) radiation giving them a significant advantage for retail, museum or even household lighting where artwork, fabrics and food can be affected by both UV and IR. If you have questions about LED performance for any application, call us and we'll do our best to provide you with the latest research-based information.
Update on the Cost-Effectivness of Replacing Standard Bulbs with LED
11/2012 - A year ago we wrote a tip where we asked the question, "Do screw based LED replacement bulbs make economic sense?" Our answer: "Probably not yet for most applications." At the time we compared an $8 halogen flood with an $80 LED flood. What a difference a year makes! That $80 LED is now around $50. So let's run the numbers again. Energy: An 11 watt LED flood will provide about the same light output as a 50W halogen flood - an almost 80% energy savings. Bulb Life: At 35,000 hours, the LED has a rated life about 15 times that of the halogen bulb. You will replace the halogen at least 12 times, spending $96, before the $50 LED needs replacement. Even if you ignore the energy savings and just compare the difference in bulb life, the $50 LED makes more economic sense than the $8 halogen. The energy savings is a bonus. The reduced ladder time for bulb changes is a bonus. Bottom line, because costs have dropped, LEDs are now a player, not just in this example but with many types of bulbs and applications.
Options for Energy Efficient Outdoor Lighting
Upgrading your outdoor lighting for better energy efficiency requires careful light bulb selection, particularly in cold winter climates. Compact fluorescent gives you a big efficiency improvement over the standard incandescent bulb in outdoor wall and pole mount fixtures, but it is a technology that is cold temperature averse. You'll get a dim, slow starting bulb at best. In some cases no start at all. The problem is the ballast. The solution is to buy CFL bulbs with integral ballasts rated for cold temperatures. Look for bulbs that list a minimum start temperature below 0 degrees Fahrenheit. For outdoor security floodlights, LED improves on the efficiency of halogen and avoids the limitations of fluorescent. This is a lighting technology that actually works better when the temperature is cold! Off the shelf LED light bulbs will start instantly and give better performance when temperatures are low. The only potential downside is when you are substituting LED flood bulbs in fixtures with ON/OFF motion sensor control. The wattage of the LED bulbs may be too low to meet minimum "load" requirements for some sensors. Test your fixture with inexpensive low wattage incandescent bulbs. It may work fine. Newer "No load" motion sensor outdoor fixtures are available. Both CFLs and LEDs can be excellent outdoor light sources year around in the right application. See Topbulb's expanding line of LEDs here. If you prefer the CFL solution, click here for some CFLs with start temperatures at minus 20 degrees Fahrenheit.
Options for Energy Efficient Recessed Downlights
Recessed downlights (or "cans") are a good place to start saving energy in residential and small commercial buildings. Many buildings built in the last 30 years are filled with downlights in entryways, lobbies and reception counters. In residential kitchens, it is not uncommon to find five to ten recessed cans, or more. These lights are often "on" many hours a day. The common bulb of choice for these fixtures is the R- or BR-shaped reflector flood. (not to be confused with the more precise optics of halogen PAR bulbs). This type of incandescent bulb is very inexpensive. It also is very energy inefficient. While LEDs are often pitched as the ultimate solution, this is one case where CFLs are competitive, at least for now. CFL reflector floods can cost five to seven times less than LEDs. CFLs are rated at 8,000 to 10,000 hours while LEDs range from 25,000 to 35,000 hours - not enough of a difference to overcome the current differential in price. If dimming is a requirement, then the advantage to CFLs is diminished because their cost goes up. Other factors may point to LEDs as the better choice for your situation, but for the basic downlight application, "instant on" CFLs are hard to beat. See Topbulb's CFL floods here, and our LED general application floods here.
Why are Some LEDs Rated for 25,000 Hours and Others for 50,000 Hours?
Question: Why do some very similar LED light bulbs declare a 50,000 hour life and others, including Energy Star Qualified bulbs, only list 25,000 or 35,000 hours? How does a customer know what to believe and which is the best buy? There are two parts to the answer. First, if "rated life" is based on the absolute failure of the LED bulb - the point in time when the bulb emits no light ("is burned out"), then most standard LED bulbs will last around 50,000 hours. But, there is a big asterisk on that 50,000 hour number and this is the second part of the answer. At 4000 to 5000 hours of "on" time, the original light output of most LEDs has already dropped well below 100%. When manufacturers test their bulbs according to standardized industry procedures, the light output typically declines to an average of 92% of the original output by 6,000 hours. The decline continues and accelerates as the bulb ages. For an LED bulb to meet the requirements for Energy Star Qualified, the bulb must be tested to determine that it still has at least 70% of the original light output at 25,000 hours and that number can be listed as the rated life. Some manufacturers can get approval for listing higher rated life. If an Energy Star Qualified LED bulb lists a 35,000 hour life, for example, it has been tested for a longer period of time to determine that it will have over 70% of the original light output at 35,000 hours. Bottom line: with Energy Star Qualified LEDs, you know the bulbs have been tested and you know when the light output declines to the point that, even if the bulb is technically still producing light, it will be time to replace it. Topbulb carries many Energy Star Qualified LED bulbs. Click to browse our complete LED inventory.
When "Infrared" Means Heat, When it Means Long Life
The term "infrared" applied to light bulbs, can be confusing. In most cases it means "heat." In other cases it means "long life." First, when does infrared mean heat? Well over 95% of the input energy to an incandescent light bulb ends up as heat. Technically, tungsten filament light bulbs (incandescent and halogen) are better space heaters than producers of visible light. So it's easy to eat lamps used in bathrooms, food-preparation areas and animal husbandry are simply incandescent light bulbs. Typically these will be "R" and "PAR" type bulbs where the reflector helps focus the infrared. Red coatings may also be used, but the color does not increase the heat, it only minimizes visible light. For specialized applications requiring higher heat output, tubular quartz halogen bulbs are available in high wattages. Where does infrared mean "long life?" Some halogen MR16 and PAR bulbs have an infrared reflective coating that prevents heat from escaping from the back of the bulb. In this case infrared means higher efficiency and longer bulb life. To view these infrared long life halogen bulbs, click here. For Topbulb's heat lamp bulbs, click here.
Ways to Solve the "Not Enough Light" Problem
How do you make a room or space that always seems not to have enough light, brighter? Most homeowners and even businesses can relate to this problem. Here are a list of things to try:
- Sometimes the solution is as simple as replacing the current bulbs with ones of slightly higher wattage.
- If the space uses incandescent bulbs, switch to halogen. The higher filament temperature of halogen produces whiter, brighter light.
- If the space uses fluorescent lighting, try bulbs with the same wattage but with higher color temperature - 4000K or higher (cool white). You'll get the same amount of light as the old bulbs, but the whiter light seems brighter to the human eye.
- If the space uses mostly track or other accent lighting, try adding a floor lamp or ceiling mounted fixture that directs the light up toward the ceiling. This works best with white ceilings that are high enough to not have "hot" spots of light. The effect of this type of indirect, diffuse light can be dramatic.
Of course, you can always call us if you need help choosing bulbs to improve your lighting.
Landscape Lighting Rules of Thumb
Whether you are lighting pathways for safety, or trees and shrubs for accent, following some basic rules will prevent your landscape from becoming an eyesore rather than an attractive addition to the property.
- Less light is better than too much light in the garden and on walkways. Too many fixtures create a visual mess rather than a pleasing view.
- Similarly, non-uniform lighting provides the most interesting visual composition. Use contrast in light levels (different wattage bulbs) as a way of focusing attention either on the direction you want people to walk, or on a primary feature of the landscape.
- Avoid glare. Use path light fixtures that direct the light on the path, not in a person's line of sight. This can be a serious problem when someone ascends steps and is looking up, directly at a beam of light ahead.
- Avoid hot spots on plants and trees. Fixtures that aim light at ornamental shrubs or up into trees can produce very interesting effects, however if the fixtures are placed too close to vegetation or tree trunks, obvious hot spots of light ruin the effect.
- Finally, if you use LED bulbs, make sure they produce a white (not blue) appearing light.
If you want more information about landscape lighting and, in particular, the best bulbs to use, please contact us.