Low Pressure Sodium Lamps

The low-pressure sodium (LPS) lamp is one of the most efficient lamp sources presently available, with some LPS lamps having an efficacy of close to 200 lumens per watt, which still outperforms current LED technologies.

The main disadvantage to LPS lighting is that it produces light in only a very narrow portion of the spectrum, and so has a terrible CRI rating and is not appropriate for use where color discrimination is important. This is why LPS lamps are often used for roadway or street lighting where the quality of the light cast isn’t as important as the quantity.

While low-pressure sodium lamps are gas discharge lamps, they fall into neither the fluorescent lighting category, nor the High Intensity Discharge (HID) lamps, and so are often considered to be in a category all their own. Like other gas lighting technologies, LPS lamps require a ballast to operate.