why are my exterior bulbs burning out so fast?

Hi, I'm hoping some of you lighting experts can help me with this problem. I'm in charge of replacing burnt lightbulbs in an apartment complex. I have found that the light bulbs are burning out within 2-4 weeks. I am putting in regular 60 watt incandescent bulbs in the round soft white style and the clear torchlight style with standard base. I am new to the contract so I don't know if this is a winter thing due to cold weather and temperature change upon lighting a cold bulb or the fixtures and or wiring is bad and it's frying the bulbs prematurely. I ordered about 60 130 volt bulbs from sylvania and hopefully these will be more durable. I have also noticed that my home exterior fixtures burn bulbs out quickIy ( I also have cheap fixtures) live in Maryland so it can get cold at night, usually not below single digits though.

Any advice on a bulb that will last and maybe as to the couse of the premature burn outs?

Thanks, David

I had this problem with the front porch light of my previous house (built in the late 50's), although I didn't have to change it as frequently as you seem to. I had read somewhere that corrosion build up on the contacts of the socket can cause excessive heat, causing the light to burn out more quickly. I used some steel wool to get the corrosion/gunk off (make sure that breaker is turned off!) Although the light still burned out more frequently than I thought it should, removing the gunk made a noticeable improvement.

I think mrg is on the right track. I have definitely had bulbs go much faster in sockets that were corroded inside, or even just loose. I don't know if it's heating, or just often flickering on and off that causes it. And this is absolutely deadly to a CF bulb which will die very quickly in a bad socket. It definitely can get a regular bulb to die too.

that being said, get yourself a meter and test the voltage level at the sockets. Things like a bad or intermittent neutral connection can cause higher voltages to be read and to cause things like this. That problem is less likely than just corroded sockets, but it's also more deadly to the people living there too and so is worth looking into!

Are these only on at night or are they on 24 hours a day? At 24 hours per day all you're going to get out of standard 750 hour incandescent lamps is around 4 to 5 weeks. Given that there is 16 hours of darkness this time of year, even if they're switched on at dusk and off at dawn you'll only get maybe 6 to 7 weeks from them. Cheap brands generally don't even come close to rated life, and I've read recently somewhere that even name brand incandescents aren't giving rated life like they used to due to manufacturing being done overseas.

James S made some good suggestions. Once you eliminate electrical problems you're down to two possibilities-cheap bulbs and vibrations. If airplanes, trains, or heavy trucks frequently pass by this building then the vibrations may be shortening bulb life.

Long term you may want to look into CFLs, metal halide, sodium vapor, or linear fluorescent. You'll save on energy with any of these and get much longer life. Even longer term but not quite yet LED will be a viable solution.

At my in-laws small 4 plex--I got so tired of the Sylvania 60 watt lamps (cheap Home Depot) that were lasting less than six week (on timer/photo cell) that I just replaced all of the fixtures with the little 13 watt exterior U tube fixtures. I have been taking care of the same place about 20 years now--and I would swear about 15 years or so I went from changing bulbs once every six months to changing them almost every month. I just don't think that they make hot wire filament bulbs like they used too...

Now I only have to replace the tubes every couple of years or so. And I replaced a flood with a 50 watt low pressure sodium (the yellow/orange color) over a 4 place carport. Enough light that people feel safe, not too much that people complain.

You might try and replace a few bulbs with twist type CFLs (or whatever shape fits the socket). It does not get cold here--so you may have to look around (and experiment) for some that operate better in cold weather (and/or damp locations). These should work fine if you don't want to, or can't, change the fixtures themselves.

On the screw base fixtures, you can place a little silicone grease on the threads to help prevent corrosion.

-Bill

I think Amigo is on the right track with the 60watt 130volt bulbs. I was having the same problem buying bulbs when on sale at the hardware store. These were constantly blowing. I got some Feit Electric 60watt 130volt heavy duty bulbs from Harbor Freight and not one has blown in over a year of regular use. HARBOR FREIGHT LIGHT BULBS

I once talked to a guy at a wholesale tool company here and he sold american airlines some generic no name bulbs by challenging them to put a few of his bulbs in their fixtures and marking the bulbs with a date stamp before putting them in. What you could do is buy several brands of bulbs and date them with a magic marker when you install them and check them often noting truly how long each brand holds up.

I live in Maryland also and used to have a lot of trouble with short lived outdoor lights, even the super expensive ones made for outdoor use. Mostly it was a winter issue though and I assumed that the heat shock when the light was first turned on was a big factor. I've changed to those little flourescant bulbs that screw into a standard light socket and haven't changed a bulb in many years now. No problem with them starting up on the coldest nights either.

There is one other possibility--if the bulbs that are failing are in easy to access fixtures--you may find that someone (or many) are using the bulbes in their own places.

Make a small mark somewhere and see if the bulbs are going AWOL and being swapped out.

Another reason to use u-tubes that would not normally be found in an appartment.

The NY subway is full of "left hand" bulbs for that very purpose (at least it was many years ago).

-Bill

Blame it of Murphy Amigo. The bulb that is hardest to change is the one which blows the most often./ubbthreads/images/graemlins/banghead.gif

Thanks for all the advice everyone. I was alos thinking theft could be a problem and was planning on marking the bulbs we replace (one bulb that had to be replaced had mysteriously jumped out of the socket and laid itself at the base of the fixture! I brought this up with the management company and they said that possibly a resident had tried to replace it themselves...I doubt that as it's unlikely they would be able to get the old bulb out but not a new one in!). We just put the 130 volt bulbs into service this weekend so it will be awhile to see how they do. I'll put a multimeter on the sockets as they need new bulbs to see how the voltage fluctuation is. The lights are currently turned on and off at dusk so they're primarily on at night.

I'm hesitant to put expensive lights in these fixtures as I'm on a contract where I supply the materials and there's not a lot of money allocated for that. Also, this problem seems to be common with exterior fixtures, as I said they blow at my house also. I did put floresents in my house (squiggly bulb with transformer at the base) and it did seem to help matters a lot but I think the light output is less as the flouresents seem to suffer in the cold.

Thanks for the link to Harbor freight. I need to also find a torch shaped clear 60 watt 130 volt bulb to go in some of the fixtures and was thinking about this one: http://www.bulbs.com/products/product_detail.asp?page=products&inventory=9004
What do you think? Remember price is an issue so wee need a good bang for the buck solution.
Thanks, David

Some of the small u-tube Fluorescents are getting down to a $1.50, IIRC, a bulb at IKEA (huge cheap furniture store)... Perhaps you can arrange with the customer a test or an updated contract based on:

Cost per month for 60 watt bulb:
60w * 10 h/d * 30 d/m * $0.10 /kwh /1000 = $1.80 / month for power.

Cost per month for 10 watt flor. bulb:
10w * 10 h/d * 30 d/m * $0.10 /kwh /1000 = $0.30 / month for power.

I don't know the watts for your specific lamps you would use, but perhaps you can "split" the power cost difference in some agreed fashion (customer pays for 1/2 the power savings or you pay for the lamps and save on overall labor costs, etc.).

In the above example, the power savings is $1.50 per month (based on $0.10/kwh). For bulbs if you pay $1.50 for the u-tube and $0.50 for the standard bulb you would be ahead in 2 months ($0.75 per month per 50 watts saved)... In reality--you may be paying closer to $5-$10 / lamp (or more, especially if they are PAR or cold weather types)... So payback is longer.

Regarding less light output--my twist tubes start out, in cold weather (45F), at probably 1/4 the light output. But after several minutes of warming up--they do seem to hit 100% of normal.

There are, of course, other pluses an minuses--you will be cutting your bulb changes by 10x (saving labor and materials), theft of the more expensive bulbs may increase, and issues of life/output/fixture vs bulb size/weather proof-ness/etc. will affect the bottom line.

In any case, it may be of interest for you to test a few lamps at one of your customer's locations and see what happens (are they happy, do the lamps last longer, do they disappear, do they start in all weather conditions, if you have a lot of old bulbs can you dump them in your area without extra fees because of the mecury content, etc.).

You could even try a few fixture changes (u-tube, LPS, HPS, or other types)--however those may be harder to convince the customer to fund up front.

-Bill

*turn the breaker off
*unscrew the bulb
*pull out the + contact with a pencil(they get pushed down and cause arcing)
*turn the breaker on and test the voltage(you might have too much or too little)
if you can use the long life bulbs then do so, they really do last longer...
if these get switched on/off alot then stay away from CF, it's the statup that kills them.