Buyers' Guide for LED Light Tubes
Posted on June 01 2017
As we have discussed in our previous article, LED is a clear winner over incandescent and fluorescent lamps in all aspects. However, many people are reluctant to upgrade to LEDs simply because of confusions regarding the replacement process. Today, we will discuss some of the considerations you might have when replacing your old tube lighting with LED tubes.
Without further ado, let us begin with the number one.
Understanding LED Tube Sizes
Tube lights are commonly sized with labels of a T followed by a number (i.e. T5). The "T" stands for "tubular" or "tube", which the shape of the light bulb and the number stands for the diameter of the bulb in eighths of an inch. For example, T5 stands for a 5/8" diameter, while T10 stands for 10/8". One thing you should remember is that generally, the narrower the diameter, the more efficient it will be. Hence, most of the time, the narrower tube will also be more expensive.
In the old days of incandescent tubes, T12 used to be the standard size. However, nowadays T8 tubes are generally the most popular, being the standard for office lighting and many household applications. T5 is generally a better and more efficient lighting, but the initial cost (currently) might not be worth it for most household applications. One thing to keep in mind, that the different sizes of the tube will not need a different fixture since most of them used similar bi-pin base. However, you might want to check the milliampere (mA) requirement of the ballast first. Regarding ballasts, we will also discuss it a little bit below.
If you are using AC or line voltage, the voltage choice would not be an issue, since you will either use 110 V or 220 V depending on your country/region. However, things will be more complicated if your house is wired for a D.C. current, for example, if you are using a home battery. (link please).
In the past two decades or so, 12 V used to be the absolute standard for low-voltage DC appliances and lighting. However, in the more recent years, people are moving towards 24 V or even 48 V options. Many people in the off-grid community nowadays also opt for standard line-voltage wiring for their off-grid houses, paired with inverters. Understandable, because inverters are a lot more efficient and a lot more affordable nowadays. Confusing? Might be, but it shouldn't be overwhelming.
In the end, your voltage choice should depend on your (intended) total energy consumption. Let us review the basic relationship between power, current, and voltage.
Power= Current x Voltage
For example, if you are looking for a total energy consumption of 10,000 Watt and you intend to use 12-volt appliances, your continuous current will be:
10,000 Watt/12-volt= 833 Ampere
833 Ampere is a very high continuous current, and therefore you will need large diameter cables, as well as large fuses, which can be costly. Not to mention, using high continuous current can be very dangerous. As a general rule of thumb, try not to exceed 100 Ampere continuous current.
While all fluorescent and incandescent lamps will need ballasts to operate, that is not the case with LEDs. Therefore, there are generally two different LED types -regarding ballasts- that are available in the market today: a plug-and-play LED, which can replace your incandescent bulb seamlessly, and a ballast-bypass LED, of which you will need a little bit of rewiring to remove the old ballast.
Which one then, should you choose? Both will perform just as well, so the main consideration here will boil down to cost. Here are some considerations you should have:
- Some T8 plug-and-play (also called direct replace) LEDs will only work with magnetic ballasts, while some others will only work with electronic ballasts. Make sure to check the package instructions.
- If you have the know-how of bypassing the ballast, and if your local electrical code allows you to, you might be better off installing your own ballast-bypass tubes, as hiring an electrician might be costly.
This is a nice read from LEDs Magazine regarding all the differences you might encounter from both types.
Also, this is a rather comprehensive tutorial for installing your own ballast-bypass tubes from Ecolocity LED. (PDF)
Understanding LED Wattage VS Lumens
In the incandescent and fluorescent era, it is a common knowledge that the higher the wattage, the brighter the lamp will be. Well, that principle does not change for LEDs. However, you might notice that many newer LED bulbs nowadays use "Lumens" instead of Wattage rating.
This happened because LEDs need very small wattage to achieve the same brightness of incandescents and fluorescents, and the wattage difference will be so small it might confuse a lot of us.
You might be more familiar with incandescent wattage and their brightness, so this simple chart might be helpful for you.
For the full read, you might want to visit CNET for the full article.
If brightness is described in Lumens (or Watts), color temperature is described by Kelvin. Color temperature is simply a description of the coolness or warmth of the light. The lowest temperature of LEDs will produce a bright red color, starting around 2700 Kelvin. On the middle side of the spectrum, you will see yellow, followed by white, and finally, ends with bluish color at around 7000 Kelvin.
'Warm' white is a description for yellowish white color, which is typically found on 3,500-4,000 Kelvin range. "Cool" White, on the other hand, is a more bluish white found on the higher color temperature of around 5,000-7,000 Kelvin.
Installing LED light tubes, arguably, is more complicated compared to plug-in LED bulbs and many other types. However, it shouldn't be overwhelming, as we have discussed above some of the principles that might make things easier.
If you have any further questions, do not hesitate to leave a comment below, or contact us directly. We will gladly help with your issues.