This month, July 2012, American lighting manufacturer will cease production of most T12 lamps as they comply with Department of Energy (DOE) regulations. Announced in July 2012, DOE has launched a phase out of the T12 fluorescent lamps and the magnetic ballasts that drive them.
Over the past six decades, the most widely used fluorescent unit has been the T12 lamp. Your shop, office or home probably has T12 fixtures.
Since T12 lamps will no longer be available, consumers will have no choice but to install newer T8 and T5 lamps. But that is good news!
Let’s say you have a four foot long socket bar with two T12 lamps (like the one in photos accompanying this blog) that is lit 18 hours a day. Replacing that with two T8 lamps can save you a whopping $18 per year at ConEdison’s current residential electricity rates. That savings pays for the conversion in no time.
Every field has its jargon. In lighting, “T” stands for “tubular” and “12” for eighths of an inch. Hence, the T12 is 1 1/2 inches in diameter. A T8 is 1 inch in diameter, and a T5 is 5/8th inch in diameter.
In older commercial and institutional commercial and institutional facilities that have not been upgraded in the past decade or two as much as 40% of the total electricity use is consumed by lighting systems. That can be as much as $1 per square foot per year for some facilities just for lights!
In newer facilities, lighting accounts for much less–usually around 25-30 percent of the building's total electricity use–largely due to installation of higher efficiency fixtures and better use of daylighting and control sensors.
The DOE has good reasons for forcing the upgrade: Time and money!
- A T8 lamp will use typically 33% less electricity than a T12, producing ongoing utility bill savings. A T5 will use even less than the T8.
- A T8 lamp will last 20% longer (36,000 lamp life hours) compared to a T12 (28,800 lamp life hours). A T5 lamp will last almost twice as long (52,000 lamp life hours) as a T12.
- Newer electronic ballasts weigh less and use less material to make than the older magnetic ballasts.
I’ll throw in a fourth reason: Color! I am tired of the pale blue light the older lamps cast on everything.
The newer T8 and T5 lamps have greatly improved color characteristics over the old “cool blue” T12 fluorescents. With the new lamps, you can choose a light output color from warmer yellows to cooler whites.
Hint: Color temperature is measured in degrees K with lower K numbers being warmer (not cooler); Typical designations on a lamp label are: warm (3000K), neutral (3500 K), cool (4100 K), and very cool (5000 K).
Beware of the ballast!
Fluorescent lamps require a ballast to regulate the voltage and current of the arriving electrical current. T12 lamps require more juice than T8s or T5s, therefore “bigger” ballasts. Originally, ballasts were magnetic and operated lamps at 60 hertz.
Newer electronic ballast operate at much higher frequencies, producing more light than the same lamp would produce at 60 hertz. For this reason, it is common to replace a 40 watt T12 lamp with a 32 watt T8 lamp (or a 75-watt T12 with a 60-watt T8) to get equivalent light levels.
Many electronic ballasts also offer reduced flicker, less heat, less noise (no buzzing!) and the capability of operating up to lamps on a single ballast.
Putting a smaller diameter lamp into the old T12 sockets without replacing an antiquated ballast may overpower the new T8 or T5 lamp. The new bulb will light up (good!), but run hotter and brighter than it should (maybe not so good!).
In short, unless the ballast is compatible with the voltage and current requirements of the new lamps, your new lamps will burn out much faster than you want them to (bad!).
Some newer T12 ballasts will not overpower a T8. The ballast should have a label telling you with which lamps it is compatible. If it does not, it is too old!
What’s in your home?
If you have socket bar tube fixtures in your home (maybe in the basement or workshop or office), replacing the lamp is simply a matter of twisting them gently. Most T8 and T5 lamps will fit into the same socket bar tombstones (the two ceramic or hard plastic tabs into which the lamp pins slide). In this case, the ballast is inside the socket bar.
If you have lighting embedded in a dropped ceiling (2x4 foot ceiling tiles are very common in offices too), open the lay in door (slide the two tabs toward the floor).
Inside you may find 2, 3, or 4 bulbs. Between the bulbs will be a “hump” that hides the ballasts. Pinch the hump together and lift the edge out from tabs to reveal the ballasts.
The old lay in fixture we removed from our home (shown in photos here) had 4 T12 lamps and 2 ballasts. If we were keeping the fixture (which we are not), we could relamp it with 4 new T8s and just 1 new electronic ballast.
Some T12 ballasts and lamps will continue to be available for special applications, including those are suitable for low temperatures (refrigerated rooms), dimmable by more than 50 percent of light output (very rare), and those designed and labeled for use in residential applications (don’t take that for granted!).
But as the photos accompanying this article show, the T12s installed in my own home were commercial fixtures, not ones designed and labeled for residential use.
PS: RPI has a great resource site for the latest on lighting research and as well as basic fact sheets.
Here's a peak at what the DOE is telling retailers of lighting; Hint: it is all about the lumens!