INDUCTION LIGHTING vs MERCURY VAPOUR / HIGH PRESSURE SODIUM

Mercury Vapour (MV) and High Pressure Sodium (HPS) are common older styles of High Intensity Discharge (HID) lighting which have been around for decades. Both technologies are relatively cheap to purchase and both have relatively long lamp lives (15-25,000hours). But both have some very bad characteristics in areas of light colour and quality as well as health and environmental problems.

   The following is a point by point comparison between Induction lighting and both MV and HPS (MV/HPS).

• The initial cost of both MV and HPS lighting would be in most cases slightly cheaper than Induction lighting. But it is the extremely long lamp life which more than counteracts the initial saving because there would need to be 3 or 4 changes to either type before any maintenance to our Induction light fittings would be required. With high Australian labour costs added in the lifetime cost of Induction lighting is very much lower.
• The instant switching of Induction lighting allows customers to firstly start working immediately instead of waiting for the lighting to heat up and when included with motion sensors, timers or programmed control systems there are even more energy savings to be added to the initial savings afforded from improved light output per watt. A simple but very effective cost saving in Warehouse lighting is to have the forklifts activate the area lighting so that only areas in use are lit and all the rest is left off. This very simple application creates extremely impressive power cost savings on a very low ROI.
• Lumen output in today’s terms is measured in Visually Effective Lumens, calculated using S/P ratios. The old lumens per watt testing method is not a clear indication of a light fitting output as it is biased to the 2800K colour temperature which was the dominant lighting type back in the 1931 and the test has remained largely unchanged ever since. Visually effective lumens for these 3 technologies are shown in Fig.1 below. As can be seen the results are very clearly in favour of Induction lighting for actual light output per watt and this translates into a 40-50% power saving on light output alone.
• Very poor Colour Rendering Index (CRI) is an issue with both MV and HPS technologies.   MV output is dominated by the blue spectrum and HPS is very poor in all but reds and yellows which happen to be favoured by the ancient lumen testing standards still in use today making HPS lighting look like it outputs massive lumens per watt, but in actual fact it does that through a very small portion of the overall lighting colour spectrum making the technology a really poor option for any form of area lighting except in some cases streetlighting but even then it is a personal preference issue rather than a light quality issue. Lightingretrofit Induction lighting has a CRI of not less than 80 which is very high across the whole light spectrum and in combination with the quality photometric spread emanating from our fixtures, make for a truly high quality area lighting solution at a very competitive price.
• Glare is generally not a major issue with MV and HPS lighting, but that said it is not nearly as low glare as Fluorescent technologies, including Induction lighting.
• Both MV and HPS technology operate on a maximum temperature basis, so that when the maximum operating temperature is reached the fixture will turn off to allow the componentry to cool down for a while. Once it has reached its lower temperature threshold it will turn back on again. This process will happen increasingly as the lamp gets older and is particularly irritating in both Warehouse lighting and factory lighting situations. Induction lighting switches on instantly at around 80% and increases to maximum output in approximately 60 seconds.
• Being based in Dandenong South, Victoria allows Lightingretrofit to distribute our Highbay lighting and Factory light fittings quickly and cost effectively across the whole of Australia’s Eastern seaboard.

Annual Power Usage Chart.

Light Source

Lumens per watt

S/P ratio calculation

Visual Effective Lumens

Hours per day

Cost per year @ 20c per kwH

Cost per year @ 30c per kwH

250W  HPS

95

0.66

15,675

12

$217.50

$326.00

250W  Mercury Vapour

65

1.1

17,875

12

$217.50

$326.00

150W  Induction

82

1.96

24,000

12

$130.00

$196.00

400W  HPS

95

0.66

25,080

12

$348.00

$518.4

400W  Mercury Vapour

65

1.1

28,600

12

$348.00

$518.4

250W  Induction

82

1.96

40,000

12

$217.50

$326.00