Business Energy Check - Progress Energy

Retrofitting With High Efficiency Discharge (HID) Lamps

The most efficient lighting sources available today are High Intensity Discharge (HID), and Low-Pressure Sodium (LPS) lamps. With the exception of one HID lamp (mercury vapor), HID and LPS lamps produce the most light per watt of any light source. They create up to one-third less heat and last as much as 24 times longer than incandescents. Most parking lots, shopping centers and sports arenas now use HID or LPS lamps, since they are especially useful for outdoor security lighting. They can also be considered for indoor use, particularly with ceilings 14 feet or higher.

Despite their advantages, these lamps do have some special considerations. Like fluorescents, they need special ballasts. They have a warm-up time of three to seven minutes, and restrike time (the delay between off and back on again) of three to five minutes, making them inappropriate for certain indoor uses such as retail clothing or interior design sales.

High Intensity Discharge (HID)

HID lamps can be used in a variety of applications, depending on the situation. The three types of HID lamps are Mercury Vapor, Metal Halide and High-Pressure Sodium.

Mercury Vapor (MV) lamps are most frequently used outside for parking and security lighting. These lamps have a white or blue-white light and limited color rendition, but are still suitable for many outdoor uses. They are the least efficient of the HID lamps (slightly less than fluorescents) and should be replaced with more efficient metal halide or high-pressure sodium lamps when possible.

Metal Halide (MH) lamps provide the best color rendering of all HID lamps; color rendition is almost as full spectrum incandescents. They can be used for merchandise display, entry lighting, or in any situation where color rendition is important and are frequently used for outdoor security and sports lighting.

High-Pressure Sodium (HPS) lamps are the most efficient and economical of the commonly used HIDs. Because of their warm golden light and limited color rendering, they are more suitable for outdoor than indoor situations. They are most frequently used as security and outdoor lighting, or in indoor areas, such as warehouses, where color rendering is unimportant.

Low-Pressure Sodium

The low-pressure sodium (LPS) lamps are less commonly used. This lamp has a limited yellow tone that renders colors poorly. In addition, a broken LPS coming in contact with moisture could start a fire. LPS applications are limited to secure fixtures.

Replacement Opportunities

Replacement of Interior Mercury Vapor and Incandescent Due to their low lighting efficiency, mercury vapor lamps should be replaced wherever possible. In areas where identifying colors is important, they should be replaced with metal halide fixtures; if color is not important, they should be replaced with high-pressure sodium fixtures.

Replacement of Exterior Incandescent and Mercury Vapor Incandescent and mercury vapor lamps in exterior locations should be replaced with metal halide, high-pressure sodium and/or low-pressure sodium lamps. If color is important, metal halide lamps are a good option.

High-Pressure Sodium Screw-in Replacements A high-pressure sodium screw-in or direct-wired adapter is available now for incandescent replacements. While the applications may be fairly limited (in storage areas, warehouses, building extensions and other areas where aesthetics are not important), these lamps can provide substantial energy savings. The restrike time is only about 30 seconds, which is not objectionable in most areas

LAMP COMPARISON CHART
If You Are Using	Retrofit With...	Watt Savings per Lamp*	Annual $ Saved** (10 Lamps)
Mercury Vapor
100-Watt	50-Watt LPS	59	$ 129
	35-Watts LPS	65	$ 142
175-Watt	100-Watt HPS	70	$ 153
	100-Watts MH	70	$ 153
	90-Watts MH	80	$ 175
250-Watt	150-Watt HPS	77	$ 169
	175-Watts MH	67	$ 147
	135-Watts LPS	99	$ 217
400-Watt	250-Watt HPS	140	$ 307
	250-Watts HPS	150	$ 329
	135-Watts LPS	272	$ 596
1,000-Watt	400-Watts HPS	610	$1,357
Metal Halide
100-Watt	70-Watts HPS	40	$ 88
	55-Watts LPS	53	$ 116
175-Watt	100-Watts HPS	75	$ 164
	90-Watts LPS	85	$ 186
250-Watt	1505-Watts HPS	100	$ 219
	135-Watts LPS	122	$ 267
400-Watt	250-Watts LPS	150	$ 329
	155-Watts LPS	240	$ 526
Watt savings will not necessarily equal original lamp voltage minus new lamp wattage, due to differences in ballasts. *Using $0.06 per kWh and 3,650 operating hours per year.