How well do T8 flourescents work at low temperature?

I have a bunch of 75 watt lamps in the garage. I’d like something brighter. I’ve thought of
A) Supplementing them with some used metal halide / sodium low bay lights (would 250 or 400 waters be way too bright for a residential garage?)
B) Replacing them with fluorescents. Standard shop lights are obviously unacceptable since it gets down to -20 degrees or so here, but I heard T8 HO lamps are better. Will they actually work when it’s this cold as they claim to.

I think that the ballast also has something to do with operatiing at ‘low’ temperatures.
I’ll be seeing my electrician buddy later, I’ll ask him. :wink:

Yeah, the ballast will be the limiting factor. The ballast should list a minimum starting temperature on the label; electronic ballasts are often 0°F, whereas a magnetic ballast would be completely unsuited to this application. Fluorescents simply do not like cold. At -20°C (I’m assuming Mdcastle was talking Celsius here), even with electronic ballasts you may have flickery, dim tubes until they warm up.

Have you considered a possible option C? Replace with LEDs. This will be a bit more costly up front, but LEDs are absolutely thrilled with cold (their nemesis, actually, is heat), they’re very energy efficient, and you can get them in directional or omnidirectional flavors depending on where they are and how you’ll use them. In addition to standard Edison screw LED lamps, you can also get T8-sized LED tubes, although for existing T8 fixtures you’ll have to do a bit of rewiring.

I do mean -20 degrees F. It gets cold in Minnesota in winter (well, maybe not that cold, but It does get below 0 F. I have thought of LEDs, but I want 2-3X the light I have now, and it seems that amount of light would be expensive, although a couple of the LED fixtures for parking garages would in fact solve the problem nicely.

Just wanted to say that thanks to this thread and BorgHunter I now know about T8 led replacements and plan to try them out. :slight_smile: Thanks.

You’re welcome! They work quite well; my dad has some in his kitchen. They use less electricity compared to fluorescents (his are 16 W, versus 40 W for standard T8 fluorescents), but they’re kind of pricey up front, and you have to rewire the fixture to bypass the ballast (and some of them have hot/neutral on one side of the tube, with unconnected pins on the other side). You should also check the color temp of the tubes you buy; wouldn’t be any good to go to that effort only to find that you bought 6500 K tubes and everything has a slight blue tint now.

This T8 shop light says it will work down to 0 degrees F.

Would you really want to work in your shop if it was below zero? :confused: You can’t even take your gloves off to work.

Have you considered running a propane shop heater? It shouldn’t take very long to heat enough for the lights to come on. You just have to get it above 0 degrees F.

I’d want it above freezing (32F) before I’d spend time working in my shop. My hands get too stiff to hold tools very well.

Edit time out got me.

I wanted to add that I’d suggest leaving a couple incandescent fixtures. Those work no matter how cold the garage/shop is. Use them for 15 to 20 minutes while the propane shop heater warms things up above 0. Then flip on the fluorescents.

Just for future reference, T8 is just the physical size of the tube. All T8 means is that the bulb is one inch in diameter. It’s like saying “How good are size 9 shoes for hiking?”

With fluorescent tubes, you put the T number over 8 and you have the diameter in inches. So, a T8 is one inch, a T12 is 1.5 inches, a T4 is a half inch.

Why that’s the standard, I don’t know, but there ya go.

I didn’t know that, thanks.

Most people don’t. It’s just one of those interesting ‘factoids’ I picked up years ago from my light bulb guy (I have a guy for everything) that’s actually a real thing and super helpful when you go shopping for a new lightbulb since you’re not at the store going “Wait, was it T8 or T12”? (Even though all the bulbs of the size say the same thing).
It makes for one less thing to remember when you look at the burned out bulb.

If the florescent fixtures are kept on does it matter then how cold the room gets? The ballast should produce a little heat and the florescent tubes get hot. So if the room fell below 0F would the fixtures stay on?

It doesn’t get cold enough here to find out.

They might dim or flicker, but I’d be surprised if they turned off altogether.