LED Flood Lights vs. Traditional Discharge Flood Lights (Metal Halide/High-Pressure Sodium)

The lighting industry has seen a significant shift toward LED technology in many applications. This includes metal halide (MH) and high-pressure sodium (HPS) lamps. LED floodlights can now replace metal halide and other discharge lights very effectively leading to superior performance, a longer lasting light and saving on energy costs.

However, to successfully replace these metal halide and sodium type lamps there are several factors to be considered to make sure the correct LED is chosen as your replacement.

Comparison of Key Performance Areas

Feature	Traditional Discharge (MH/HPS)	LED Flood Lights
Energy Efficiency (Lumens per Watt)	Moderate (Typically 70-110 lm/W)	High (Typically 120-170+ lm/W)
Lifespan	10,000 to 20,000 hours, ballast replacement is often required	50,000 to 100,000+ hours, minimal maintenance needed
Light Quality (CRI)	MH: 65-80 CRI; HPS: <40 CRI	Typically 70-90+ CRI
Color Temperature (CCT)	MH: Cool White; HPS: Amber/Warm	2700K to 6500K available
Startup Time	5-15 minutes for full brightness	Instant, gives full brightness almost immediately
Dimmability	Poor or requires specialized ballasts	Excellent (Easy integration with controls)
Maintenance	High (Frequent bulb and occasional ballast replacement)	Very Low (Essentially maintenance-free)
Environmental Impact	Contains potentially hazardous materials (mercury)	Generally mercury-free and recyclable

Key Considerations for Replacement

To find a successful LED replacement you will need to do more than match the wattage; you will need to compare the lumens as LEDs will generally use less wattage to produce the same amount of light and you should also check that the light distribution is the same or better.

1. Lumens and Efficacy

LED fixtures are significantly more energy efficient. A lower-wattage LED fixture can often produce the same amount of usable light as a much higher-wattage MH fixture. For example, a 400W metal halide fixture can be effectively replaced by a 150W to 200W LED flood light. This will have a 50-60% immediate reduction in the amount of energy used for the same amount of light.

2. Light Distribution and Optics

This is the most critical difference. Traditional discharge lamps emit light in all directions and rely on a reflector to direct the light. This often results in wasted light and glare.

LED Advantage: LED fixtures focus the light in one direction. They use advanced optics (lenses and reflectors) to precisely focus the light where it is needed. This means that even if they have a slightly lower lumen output, the usable light delivered to the target area can be higher.
Replacement Requirement: Ensure the replacement LED fixture has the correct beam angle (such as 3H x 3V, 5H x 5V) to match the original coverage pattern. You can make use of a photometric study for larger projects to ensure the replacement lights will have the same area coverage.

3. Thermal Management

LED lights are sensitive to heat. A high-quality LED flood light will have robust heat sinks and materials to dissipate the heat effectively. If you have any concerns about how long the LED light will last you can check the manufacturer’s warranty. A long warranty such as 5 years will confirm that the manufacturer is confident in the light's thermal design and quality.

4. Color Rendering Index (CRI) and Color Temperature (CCT)

CRI: LED lights almost always have a much higher CRI which means colors will appear more vibrant and natural. This is a significant improvement over HPS lights, which cast a strong orange/amber glow.
CCT: LEDs are available in a wide variety of colour temperatures and the more modern LED lights will have the option to choose which colour temperature you would like ranging from 2700k to 6500k.

In summary, LED flood lights require a few considerations before you change your metal halide or sodium bulbs over to them. They are however much more energy efficient, longer lasting and have a better CRI.