Someone posted an article where it cost a lady $2,000 to clean up after she broke a CFL. Something to think about.

(We've beens swapping out CFLs for LEDs where we don't need a lot of light, but still use CFLs in most places)

1. If the bulb was base up, this can happen on cheaper styles as they don't use high temp components. This can also happen if the lamp is in a high-vibration area.

2. If it was a non-dimmable CFL on a motion detector or dimmer circuit, this can happen - and it can overheat your dimmer or motion detector as well.

3. CFL's - like ALL fluorescent lamps - including the tube ones in your shop or kitchen - have tiny amounts of mercury. As far as phosphorus, any CRT (tube) monitor for a television or computer has MUCH more phosphorus (as well as lead, cadmium and a bunch of other nasties).

4. 80% of the lamps in my home are CFL's - I hate them, my wife hates them, but we have seen the effects on the electric bill and we use them in almost every room of the house.

5. I now use LED lights in my office, I like these much better than CFL's, but I need 5x more lamps to get to the same lighting levels I had with CFL's, so I have a fairly heavy investment there. They are cool to the touch, they dim (in a slightly odd way) they burn at any angle with no problems and they use so much less electric that it's incredible. My office went from 3 60w incandescents (180 watts) to 3 12 Watt CFL's (36 watts) to 15 3W LED's (45W). I am gradually replacing outdoor lighting with LED's, and my son just likes the cool blue version of LED and that's all he uses in his room.

They do fine in the cold - they just need to warm up for a few minutes. I use them in my unheated garage and my shed.

As an aside - you want to leave a CFL ON once it's up to temp - cycling on and off - like in a closet or bathroom - dramatically shortens the life of the lamp. For my utility areas with CFL's I have a timer switch I found - it's a pushbutton thing - you press once for 10 minutes, again for 20, then 30 then 60 and then "hold" on. That way the lights get at least aa 10 minute on cycle. Had vastly improved the life of these CFL's.

If you think of CFL's as equipment - not some disposable item like duct tape or a paper bag - you'll quickly learn how to benefit from them. For example, in the last power outage from the big storm, my little 3600w generator was basically unaffected by lighting loads in my home, leaving most of the power for motor loads - well pump, septic pump and refrigerator - and my generator fuel consumption was very low as a result.

Inverted: Strike One
basement - high vibration load (from steps upstairs): Strike 2
basement - high number of on/off cycles: strike 3

I'd suggest the Phillips brand going forward and read the box for use in enclosed or inverted fixtures. They will say if it's OK.

I've found these LED replacement E27 bulbs to be good performers so far;

http://www.dealextreme.com/details.dx/sku.13421

They are expensive but give excellent performance. Typically it will use around 7-8 Watts (measured using a power meter) and give around 500 Lumen so give around 70 Lumen per Watt, just slightly higher efficiency performance than an equivalent power CFL. i.e. the same efficiency of the larger 20+ Watt CFL bulbs. 2 or 3 of these will light a medium sized room, but with none of that 3-4 minute warm up delay of CFLs. LED based ligh bulbs also tend to be more robust than CFLs. The colour of the ones I have recieved appear to have a medium warm natural light rather than the more typically blueish tint of some other LEDs. Colour temperature I would estimate would be around 4000-5500K rather than the yellowish colour of standard Halogen.

They are around 7-8 times more expensive than CFLs but they have a design lifetime 7-8 times that of a CLF. They should typically have a domestic lifetime of 20-30 years in normal operation.

Years ago I had a GE Circlite (forerunner of the CFLs, sort of) whose ballast overheated when the bulb finally wore out. Nasty electrical smoke -- the smell is distinctive. No damage to the house, but years later I'm still cautious about putting CFLs in any kind of enclosure that would concentrate heat.

That said, I use them most everywhere, except for a handful of LED bulbs. My CFLs light up at -25C, though as others said, it takes a little time for full output.

Or it could just be a bad bulb...

1. Wrong. According to mfg, this bulb is OK for inverted use. That was the first thing I asked the GE rep to confirm what I thought I had read on the packaging when I purchased the bulbs.

2. Wrong. The ceiling in the part of the basement in question is a reinforced concrete slab with almost no overhead traffic. Unless we get an earthquake, the ceiling isn't moving. The guy who built the house during the height of the Cold War called it "The Shelter" on the blue prints. The room is literally a poured concrete box.

3. Wrong. This light is probably the least used light in the house. The last time I turned the light on in this room was probably a month ago. I turned it on and left it on today for a few hours to move stuff into the room.

Thanks for the suggestion. I will check these out.

The smell and smoke point to ballast failure so no worries about mercury.

Turn it off immediately due to fire hazard. That heat is the 15A circuit trying to short-circuit ... the heat is cause to get excited. A nice thing about incandescent bulbs is that all failures in the bulb lead to an open circuit - it safes itself. That's not so with a CFL.

The smell is probably a fried capacitor in the ballast and nothing to do with what's in the glass.

Once cool remove it carefully so as not to break the glass.

Unfortunately people want CFL's to cost about what incandescent bulbs cost even though there is a lot more to a CFL. The ballast is what gets cost-reduced past the point of reliability.

Panasonic sells some CFLs that are rated for use in enclosures but unless explicitly marked (and priced) for that a CFL must be used in a way that keeps both the base and bulb from overheating (if the glass part gets too hot the bulb gets dimmer earlier in its life). Inverted use should be OK as long as the heat from the bulb can escape past the base.