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A White Paper by Stan Walerczyk

His hibay, interior lighting and exterior lighting seminars further discuss how EHID compares with LED and how they compare with other technologies. Complete bio, seminar schedule, testimonials and other information are available at

Executive Summary:
EHID, which this document focuses on 45 – 320W 20,000 – 30,000 hour rated CMH lamps, and LED can often cost effectively replace or be used instead of:

  • HPS
  • Standard or probe start MH
  • Pulse start quartz MH driven by magnetic ballast
  • MV
  • LPS
  • Induction

Although most people are quite familiar with LEDs, EHID is often a secret. The above table shows that EHID and LED will probably both improve more rapidly than most other technologies. EHID and LED can have about the same performance and use about the same wattage, but EHID often costs less, especially when existing fixtures can be retrofitted. Parts and labor to retrofit a well designed fixture that is still in good shape with EHID may cost one fourth compared to replacing that fixture with an LED one. Some fixture manufacturers have high performance reflector kits designed for specific CMH lamps for their fixtures that have been in use.

Two 315 – 320W CMH lamps with two electronic ballasts is often more cost effective than LED to replace 1000W HPS or MH, because so many LEDs would be required, which increases cost. There are some EHID fixtures and kits with two lamps and one 1-lamp electronic ballast with only one lamp on at a time, so some kits and fixtures will not have to be relamped for up to 60,000 hours, which is about the same life as LED fixtures.

EHID and LED can eliminate the yellow light and low color rendering of HPS and LPS. Some CMH lamps are warm color tone 2800 – 3000K, which may be preferred to 6000K or even 4000K LEDs.

Some electronic ballasts for EHID are dimmable, so controls can be used. Some CMH lamps are being developed to have very short dimming time down to 50% and back up to maximum light output, allowing them to be used with high/low occupancy sensors.

In general, we should focus on footcandles per watt or dollars per footcandles where the light is needed instead of LPW. Both well designed EHID and LED fixtures can be cost effective with regards to footcandles per watt and dollars per footcandles.

Some lighting professionals feel more comfortable with time proven technologies, including EHID, compared to LED.

Several applications will be discussed. Long term benefit, which is a type of cost of ownership, is included, because that is much more important than payback.

It will be an LED or another type of solid state lighting world, but right now, don’t automatically go with LED without comparing it with EHID.

Induction is not that good compared to latest generation EHID and LED. EHID and LED will continue to rapidly improve, while mature technology induction will lag further behind EHID and LED down the road. No matter what induction people state, don’t buy it for most applications.

These are all of his free white papers, which are downloadable:

  • EHID & LED For Exterior, Hibays, Etc.
  • High Bay Occupancy Sensors: A Comparison
  • How to Retrofit Parabolic Troffers
  • LED vs. Induction – Full Cut-Off Streetlights, Etc.