Can a high-pressure sodium bulb be replaced by metal halide?

[Sum Guy]

I've got an outdoor parking-lot fixture with high-pressure sodium bulb that has burned out. The bulb is a 70-watt Sylvania Lumalux:

Can I replace this with something that puts out a more whiter light, like maybe a metal halide bulb, or is the ballast in this fixture specific and can only with with high-pressure sodium bulbs?

[RBM]

The ballast is specific to the type of vapor and wattage

[Art Todesco]

There are some specific MH lamps made to work with HPS ballasts. But, there are usually pretty expensive and are not as efficient at a "real" MH lamp working with a MH ballast. My old church was built with 26 400 watt HPS fixtures. We found 2 manufacturers (maybe even 3) that made a MH lamp to work with that ballast. It was a very pricey mistake made by the archetect/engineer that the church ultimately had to pay for.

[Sum Guy]

Does that mean that I can't (or shouldn't) replace the original 70 watt HPS with, say, a 100 watt bulb (assuming it was the same size and would fit in the fixture) ?

[Evan]

It means that running a light fixture with a mismatched lamp/ballast will do several things:

a. reduce lamp life b. consume more energy for less lighting output c. burn out the ballast d. cause the lamp to catastrophically fail

If you want a brighter lamp in your fixture, you need to have a qualified electrician retrofit your fixture with the proper ballast which will support using that lamp in the fixture... If the new desired lamp will even fit inside your fixture housing...

~~ Evan

[whacko]

I wouldn't feel too bad about it. The church robs the people, and now they got to give some money back. Sounds fair to me....

[Tony]

I took the transformer out of mine and rewired it to take regular bulbs. I have a CFL in it that gives me all the light I need there. No reason to light up the whole mountain. It still uses the dusk to dawn circuit which has a relay so CFLs will work. Those original lamps do put out some really ugly pink light.

[blakeiddings1234]

Just to reiterate no you cannot but the compact fluorescent idea was great it's very easy and extremely cost-effective and you don't have to have a certified electrician to do it incredibly easy