Sodium lamps—producing up to 180 lumens per watt—have the highest efficacy of all commercially available lighting sources.
Even though they emit a yellow light, a Sodium lamps shouldn't be confused with a standard high-pressure sodium lamp a high-intensity discharge lamp. Low-pressure sodium lamps operate much like a fluorescent lamp and require a ballast. The lamps are also physically large—about 4-feet long for the 180-watt size—so light distribution from fixtures is less controllable. There is a brief warm-up period for the lamp to reach full brightness.
With a CRI of 0, Sodium lamps are used where color rendition is not important but energy efficiency is. They're commonly used for outdoor, roadway, parking lot, and pathway lighting. Sodium lamps are preferred around astronomical observatories because the yellow light can be filtered out of the random light surrounding the telescope.
AET Group Green Design-Build Energy Conservation Consultant, Pre-Acquisition Due Diligence, Consultants For Commercial, Industrial & Retail Energy Solutions For Renovations & Restorations & New Construction
