CFL Warm-Up Times: 4 Bulbs Put to the Test

TCP TruStart Ad

You know the feeling. You just came home from the hardware store with a blister pack of brand new, energy-saving CFLs. You screw them in and hit the switch. “Oh, this is gonna be good,” you say to yourself. You’re going to save tons of money and your bulbs are gonna look great! Then you notice they’re dim, really dim. Defeated, you retreat to another room to find your receipt. But then, when you return a minute or so later, they’re as bright as you expected them to be! What sorcery is this?

Everyone has had this experience with their first batch of CFLs, though maybe it wasn’t as melodramatic. To understand why compact fluorescents start off dim, you have to know a bit about how fluorescent lighting works. Unlike an incandescent bulb, which creates light by heating a filament until it is white-hot, fluorescent lights use cathodes to heat a special gas or mix of gases to create UV light. The UV light is then filtered through phosphors to create white or colored light. To do this however, the cathodes have to warm up.

The Setup

Every new CFL on the market uses different proprietary technology to shorten the bulb’s warm-up time, with varied results, so we chose to test four of our best-selling 60 watt CFLs. Though this is far from a scientific study, here’s how we conducted the experiment: We screwed each bulb into a lamp, and set a light meter about one foot to the side the lamp. We propped up the light meter so it was roughly on the same horizontal plane as the CFL’s midpoint. We then turned on each bulb and used the light meter to record the maximum light output of the bulb. Finally, we replaced the bulbs with identical bulbs of the same make and model (using the already warm bulb would have skewed our results). We then switched the bulbs on and recorded the time it took to meet the previously recorded maximum output.

Bulb One: Energy Miser

The first bulb we tested is a 13 watt, 2700K CFL from Energy Miser. Just over $1.00 each, this bulb is not only the most inexpensive of the bulbs we tested, but it’s also our best seller. The manufacturer doesn’t make any claims about the bulb’s warm up time, though our customers have given it an average 5-star rating. In our tests, the bulb reached its maximum output in 2 minutes, 2 seconds. That’s not exactly quick, but according to most manufacturers, it’s about on par for a typical CFL.

Bulb Two: TCP TruStart

The second bulb we tested, a TCP TruStart, is a fairly new addition to our product line. In their spec sheet, TCP claims this bulb is the “Best on/off CFL ever made!” Unlike the previous bulb we tested, TCP does make a claim about this bulb’s warm-up time; specifically, TCP says the CFL has a less than 30 second warm-up time. Our tests showed this claim to be mostly true, with the bulb reaching its full brightness at 38.7 seconds.

Bulb Three: Sylvania DULUX EL

The third bulb we tested is from the “big three” of lighting manufacturers, Sylvania. Sylvania also doesn’t make any specific claims about warm-up times for this 13 watt CFL from their DULUX EL family, nor do our customers (who give it an average 4-star rating). So how did this name brand product fare? Pretty well, it turns out. The bulb reached its full brightness at 1 minute, 7 seconds. That not as good as the TCP TruStart, but it’s nearly twice as fast as the Energy Miser.

Bulb Four: TCP InstaBright

The final bulb we tested is a little different from the other four we tested. This covered CFL from TCP has a glass cap over the fluorescent spiral tube so that it looks more like a typical A-shape incandescent bulb. In their InstaBright G2 brochure, TCP claims the bulb has the “Fastest run-up time and significantly improved light build up time,” and it is supposed to reach full brightness in 45 seconds. Surprisingly, this bulb beat even its own estimates, reaching full brightness in only 35.1 seconds!

Which of these bulbs should you buy? It depends how much you’re willing to pay and how much you value fast warm-up times. There is a spread of more than $4.00 between the cheapest and most expensive of these bulbs. Is a few seconds quicker to reach full brightness worth the premium? Let us know what you think in the comments, or connect with us on Facebook, Google+, and Twitter.

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Benjamin is a writer for 1000Bulbs.com.

  • Don

    No one who is used to incandescent bulbs achieving full brightness instantly cares why CFLs take forever to reach full brightness. Yes 30 seconds to 2 minutes is “forever” to them. That annoying characteristic (defect) of CFLs is one reason why many people are “turned off” to CFLs and are pissed off at the government for trying to force them to use CFLs by banning the most commonly used incandescent bulbs that behave the way consumers expect them to.

    My suggestion to the manufactures if CFLs: Get those cathodes to warm up instantly! Don’t know how? Figure it out. The public expects “instant on at full brightness”, instantly, not when the CLF is good and ready. Because if this defect and other factors, CFLs are doomed to obsolescence. Let’s hope that LED technology is perfected soon and made economically feasible (currently they cost way too much) so that we can have our cake ( no annoying characteristics) and eat it too (greatly reduced energy consumption and long life). Until then, many consumers will continue to reject CFLs, because to them, as light bulbs go, they suck! And here I am a strong advocate of energy efficiency and a moderate user of CFLs (they just don’t cut it in all situations).

    • Benjamin Rorie

      Those are great points you make, Don. I can totally understand why some people like yourself are averse to using CFLs throughout their home. However, I do believe there is a place for them. There are some areas in our homes where quick brightness is less important than being able to leave a bulb on for a long period of time. In my home, for example, I keep CFLs in table and floor lamps that are on for hours at a time. In my hallway and closets, though, I use incandescents because I need short periods of quick, bright light.

      Of course, LEDs could be perfect for both applications.

  • Eddy

    I put in TCP spirals, type As, globes, torpedoes, dimmables in every conceivable place except a few closets, a bedside lamp which is on for short periods. I used GER30 15 watt outdoor reflectors to light my driveway. The encased spirals take a little while, but even at start up they’re bright enough – which I don’t understand because they should warm up faster (having more clothes on you know). The Outdoor reflectors take the longest at several minutes, so I plan ahead. Spiral is sexy, incandescent is decidedly not, and I’ll be patient with sexy. 😉

  • Mike

    I just bought some new Philips 14w enclosed CFL’s and they are taking more than a minute to be useful. I have them in my kitchen and I’m not impressed. The CFL’s I replaced with these came on faster – almost instant on.

  • mike hunt

    I too have noticed that different brands of lamps take varying amounts of time to reach full brightness, and I believe that the reason for this is the composition of the mercury in the lamp. Good old linear fluorescent bulbs used to have a good dose of good old liquid mercury, as did some of the earlier CFL lamps that I was used to instantly starting. Newer lamps, in response to environmental concerns do not use liquid mercury, but a mercury amalgam, similar to the old tooth fillings. This is a solid pellet inserted into the bulb when it is manufactured. (watch the video that TCP has online to see the manufacturing process) This amalgam needs to heat up to release the mercury vapour that is needed to produce UV rays to light up the phosphor. Watch the lamp as it is warming up. If the lights are hung base up the tube will start brightest un the lower portion, and will follow the spiral up to the top. If base is side mounted, the lower portions of the tube lighs up first, and if base down, the ends start brighter and the light slowly works its way through the tube, as the mercury warms and distributes the mercury vapour through the tube. Old lamps with liquid mercury vaporized much faster. I am no expert, but I believe this is why the new ones start so dim.

  • Jason

    Can you redo this test after running the bulbs for a week or two? A lot of people on Amazon have given the TCP instant bright bulbs a one star review. They say they do come on instantly at first, but after about a week turn on as slowly as any other CFL bulb. Currently they only average a one star review. This makes me think testing performance right away isn’t a fair test, and they need to be run for a week before you can get a real accurate understanding of how they perform.

    • Jordan Loa

      Thanks for contacting us, Jason.

      Which TCP bulb are you referring to? Can you send us the link? This would help us greatly in getting to the bottom of this.


  • Trish Zemsch

    I Purchased the covered Ge bright start 20W bulbs to eliminate the dim starts. I use them in Apartments. I loved the quick start but intermittently they dim. Is this normal? I read the reviews and no one mentioned this. I tried 4 bulbs in 4 different lamps, wall fixtures and desk lamp. I expected such good results that I threw away the packaging. They ran $11.99 per 2 pack.

    • http://www.1000bulbs.com Will Parsons

      That depends on what’s causing the dimming. It could be anything from a microwave turning on, to added power drain due to a heating system turning on or off. Look for any large power drain when they dim.