Saturday, August 6, 2011

PAR20 LED Flood Lamp Bulb Comparison

GE LED7PAR20/NFL, Phillips NR63R4-7W-Q100, LED8PAR20/DIM/830/NFL25, Eco-Lite 9 watt.

All are NFL (narrow flood) lamps except possibly the Eco-Lite, for which the beam width is not given. All were purchased on Most were $30, with the GE costing $38. All are made in china.

   GE  Phillips Sylvania    Eco-Lite
Part Number on Bulb   LED7PAR20/NFL   NR63R4-7W-Q100   LED8PAR20/DIM/830/NFL25   None
Rated Power (W) 7 7 8 9
Rated Lumens 200 155 350
Observed Brightness 10 8 10 9
Observed Beam Width SameSameSameWider
Rated Voltage (V)110-127120120
Rated Current (mA)1009575
Color Temp K300031003000
Rated Hours20,00040,00050,000
UL ListedYesYesYesNo
Measured Current (mA)808050160
Measured Power (W)5558
Measured VA99618


The rated lumens are baloney. These bulbs compared reasonably well with a 50W Sylvania PAR20 Halogen NFL (narrow flood) lamp rated at 550 lumens. Further, there was no difference in power consumption or brightness between the GE and the Sylvania, even though there is a huge difference in rated lumens.

The rated life means the hours before the brightness drops below 70% of initial brightness. Lifetime numbers for light bulbs are notoriously optimistic - you may have noticed that with CFL’s. Lifetime will depend a lot on the bulb’s local environment - how much cool air can come in contact with the bulb.

"Observed brightness" is totally subjective, a 0-10 scale, where 0 is dark and 10 is the GE and the Sylvania. Comparisons were done in side-by-side tests, using two bulbs at a time, projecting on a white wall. To my eyes, the GE and Sylvania were equal in color, with the Phillips slightly yellower (warmer) (even though it is rated for a slightly bluer color temperature), and the Eco-Lite was actually bluer (cooler). Since the Eco-Lite has a somewhat wider beam than the others, it might actually be a little brighter than it seems, with the light dispersed more broadly. Similarly, the halogen bulb used for comparison also had a wider beam, and all of the LED bulbs appeared bright by comparison.

The dimmer used to test the Sylvania and Eco-Lite has a detent switch for "off," and moving the lever just above "off" produces a lowest setting which causes all lamps of all kinds to light, at least a little. The Sylvania was still rather bright at the lowest dimmer setting, whereas the Eco-Lite dimmed farther, though not as smoothly. The GE and Phillips are not rated for a dimmer and were not tested.

The tests were done on just one sample of each bulb. Tests on a larger number and from different manufacturing lots could give different results.

The Eco-Lite bulb came with no documentation, except for a sheet of cautions saying what NOT to do, e.g. do not eat the bulb while it is plugged in, etc. No product information. There is no product information at all printed on the bulb. Absence of a UL symbol means it is not UL Listed, thus not tested for possible shock or fire hazards. It’s about the same price as the others, so it would be my last choice among the bulbs.

The Sylvania and the Eco-Lite are maybe a half inch shorter than the other two.

I have used several of the GE bulbs for over a year now, and they have performed flawlessly. However, they are the most expensive. The Sylvania bulbs are lower in cost, dimmable, and smaller, so they are my choice now.

Engineer Stuff:

Actual current, power, and VA (volts * amps) were measured on a "Kill-A-Watt" brand in-line power meter, a handy device but not a precision instrument, though I believe it gives good enough numbers for this purpose. Further, the line voltage was 113V, not the rated 120V. However, the same instrument and voltage were used for all bulbs.

According to that meter, each of the lamps actually consumed about 5 watts except the Eco-Lite, which consumed 8 watts. Also, surprisingly, the current drawn by the Eco-Lite is at least twice that of any other bulb. That does not translate into consumed power, though, because of something called the "power factor.” You are billed for the watts, not the current or the volt-amps.

No comments:

Post a Comment