We typically have been buying light bulbs based on how much energy they consume (Watts), regardless of light emitted (Lumens). All that began to change with the advent of different types of light bulbs, such as CFL, halogen, LED, etc., since they consume different amounts of energy to produce the same amount of light.
Lumens measure how much light you are getting from a bulb, regardless of type and regardless of energy consumed. This equalizes all bulbs and types for comparison. More lumens means brighter light.
Another measurement that is not well understood is Kelvin. It is a scale of measurement for the color a light produces. The higher the Kelvin (K) number, the cooler the light appears. Most bulbs will be in the 2,500K to 6,500K range, with 2,500 being the warmest and 6,500 the coolest. Kelvin is usually ignored except for specific lighting circumstances. The 2,700K to 3,000K range is warm and inviting, 3,500K casts a neutral light, 4,100K casts a cool and bright light, 5,500K to 6,500K range is closest to daylight.
To compare brightness of typical old style bulbs, here are a few examples:
Replace a 100-watt incandescent bulb with a bulb that gives you about 1600 lumens,
Replace a 75W bulb with a bulb that gives you about 1100 lumens,
Replace a 60W bulb with a bulb that gives you about 800 lumens,
Replace a 40W bulb with a bulb that gives you about 450 lumens.
Sixty watt bulbs used to be the standard as they offered the best compromise of minimum required light and cheaper cost. Now that energy cost has been so greatly reduced, 1100 lumen lights are becoming the standard minimum. Brighter lights make it easier to see and make everything look better, especially when trying to sell your house.
Showing posts with label Kelvin. Show all posts
Showing posts with label Kelvin. Show all posts
Apr 8, 2016
May 4, 2011
Some Illuminating Thoughts
On Jan. 1, 2012, 100-watt incandescent bulbs will start disappearing from store shelves.The front of the new bulb labels will list energy cost and lumens, which can vary widely even for bulbs consuming the same amount of energy or wattage. Lumens already appear on bulb packaging, but we often overlook the fine print.
The back will list the bulb's expected life span, energy consumption and its "light appearance," or color, which is measured on a temperature scale known as Kelvin (K). Lower Kelvin numbers mean the light is more yellow; higher Kelvin numbers mean it's whiter or bluer. The traditional incandescent, which gives off a warm, soft and almost yellowish light, has a temperature of about 2,700 to 3,000K — similar to most halogens. LEDs' temperatures range from 3,300 to 5,000K while CFLs can be quite warm (2,700K), neutral or cold (6,500K).
For kitchens and work spaces, where a brighter and whiter light is desired, look for bulbs marked 3,500 to 4,100K. For a cooler, bluish light akin to daylight, good for reading, look for bulbs with 5,000 to 6,500K.
For CFLs, the back label also notes that the bulbs "contain mercury" which, in high enough doses, can cause tremors, mood swings, headaches and insomnia. (CFLs have, on average, 4 milligrams of mercury, while older thermometers have about 500 milligrams.) No mercury is released unless the bulb breaks. Besides being expensive, I have tried them in my ceiling fans and about one in four burns out within a few months. The new label lists a government website for tips on how to clean up broken pieces and dispose of the bulbs. This is very scary stuff.
Here is a link to a Youtube explaining the new CFL bulbs LINK This Texas congressman is not happy. If these bulbs are really that good, we would have already bought them and they would not have to be forced on us.
The back will list the bulb's expected life span, energy consumption and its "light appearance," or color, which is measured on a temperature scale known as Kelvin (K). Lower Kelvin numbers mean the light is more yellow; higher Kelvin numbers mean it's whiter or bluer. The traditional incandescent, which gives off a warm, soft and almost yellowish light, has a temperature of about 2,700 to 3,000K — similar to most halogens. LEDs' temperatures range from 3,300 to 5,000K while CFLs can be quite warm (2,700K), neutral or cold (6,500K).
For kitchens and work spaces, where a brighter and whiter light is desired, look for bulbs marked 3,500 to 4,100K. For a cooler, bluish light akin to daylight, good for reading, look for bulbs with 5,000 to 6,500K.
For CFLs, the back label also notes that the bulbs "contain mercury" which, in high enough doses, can cause tremors, mood swings, headaches and insomnia. (CFLs have, on average, 4 milligrams of mercury, while older thermometers have about 500 milligrams.) No mercury is released unless the bulb breaks. Besides being expensive, I have tried them in my ceiling fans and about one in four burns out within a few months. The new label lists a government website for tips on how to clean up broken pieces and dispose of the bulbs. This is very scary stuff.
Here is a link to a Youtube explaining the new CFL bulbs LINK This Texas congressman is not happy. If these bulbs are really that good, we would have already bought them and they would not have to be forced on us.
Jan 13, 2010
Trees Are Bad?
I read that cutting the rain forest is part of causing global warming, because trees absorb Co2, and greenies say we should plant trees. Well, here is an article that says trees can cause warming.
"Although temperatures have risen throughout the globe, they've gone up most dramatically in the Arctic. Past warm periods indicate that deciduous tree (deciduous trees lose their leaves in the winter) expansion into the Arctic is a common occurrence when the region warms up, so a new study has looked into the impact trees could have on the regional climate.
As expected, the increase of the leafy trees would result in less reflective ground, but the study suggests they could also induce more cloud cover and an increasingly warm surface and ocean that have more turbulent weather patterns. The simulation indicated that the expansion of leafy trees, by their ability to increase water vapor and absorb light, would result in an increase of the surface temperature in the Arctic region of about a Kelvin (1K is about 1.8 degrees Fahrenheit) over the next 20 years. " Taken from ARS Technica Dec, 30, 2009. Trees cause clouds, warm up the earth and are bad - trees are good and eat Co2. Hmmm, The trees I sit under in the summer seem to cool me off quite nicely and their leaves drop in the fall, so they don't block the sun in the winter.
"Although temperatures have risen throughout the globe, they've gone up most dramatically in the Arctic. Past warm periods indicate that deciduous tree (deciduous trees lose their leaves in the winter) expansion into the Arctic is a common occurrence when the region warms up, so a new study has looked into the impact trees could have on the regional climate.
As expected, the increase of the leafy trees would result in less reflective ground, but the study suggests they could also induce more cloud cover and an increasingly warm surface and ocean that have more turbulent weather patterns. The simulation indicated that the expansion of leafy trees, by their ability to increase water vapor and absorb light, would result in an increase of the surface temperature in the Arctic region of about a Kelvin (1K is about 1.8 degrees Fahrenheit) over the next 20 years. " Taken from ARS Technica Dec, 30, 2009. Trees cause clouds, warm up the earth and are bad - trees are good and eat Co2. Hmmm, The trees I sit under in the summer seem to cool me off quite nicely and their leaves drop in the fall, so they don't block the sun in the winter.
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