LED VS High-Pressure Sodium(HPS) – Which Outdoor Lights Are Better?

All About High-Pressure Sodium Lights

The popularity of High-Pressure Sodium Vapor (HPS) Lights spiked when the concept of grow lights came into being. They have been used in horticulture as HPS lamps emit light rich in the red spectrum that promotes plant growth and flowering. Since then, technology has evolved, and there are many more efficient options. But what are they, and can you use them in your project? Let’s find out.

What are High-Pressure Sodium Lights?

HPS and LPS (Low-Pressure Sodium) Lamps belong to the family of Gas Discharge Lamps. They create light by passing an electric current through ionized gases like argon, neon or krypton. The electric charge energizes gas atoms inside the bulb. This creates moving ions that collide with other particles to produce light. The bulb’s gas type sets the color of the light we see.

The main difference between HPS and LPS is, just as the name implies, the operating pressure inside the tubes is different. HPS uses vaporized sodium metal and other elements, such as mercury, to balance the output color temperature. A high-pressure sodium arc is contained in an aluminum oxide arc tube because the sodium arc is highly reactive. On the other hand, LPS consists of a borosilicate glass arc tube.

Output Color Properties of HPS

Before heading to the pros and cons, let’s look at what color temperature range HPS light falls into. The standard HPS output lies between 1900 to 2000 degrees Kelvin. This corresponds to a distinctive yellow color. HPS lights have a color rendering index (CRI) ranging from 20-22. They show the right primary colors but are unsuitable for greens, blues, and violet.

Nowadays, color-corrected HPS lights are in use because they offer higher CRI of up to 80 and a color temperature range of 2600-2700K compared to standard HPS lights. The output of such HPS lights is similar to that of incandescent bulbs.

Advantages Of HPS Lights

Coming to the part you’ve most certainly been waiting for; the benefits of HPS lamps. HPS lamps have a lot to offer, which is why they are widely used in specific industries.

• Energy Efficiency: HPS Lamps are better than incandescent and mercury lamps. These lamps are approximately seven times as efficient as a regular incandescent lamp and about three times as efficient as a metal halide or a mercury vapor lamp.
• Plant Growth Efficacy: If we talk about efficacy (the efficiency of a lamp to convert electricity into light that is useful for photosynthesis), HPS is not very far in competition with LEDs. However, HPS emits a broad spectral output light, most of which is rendered useless for plants. LEDs, on the contrary, are much more efficient in this sense, as their output can be optimized to emit only valuable wavelengths.
• Warm-Up Time: With most HPS lamps, the average warmup time spans about 4-6 minutes. Compared to mercury halides and incandescent lamps, HPS requires much less time to reach its peak output state.
• Service Lifespan: HPS lamps have a good and long life of 24,000 hours.
• Lumen Retention: These lights have excellent lumen maintenance. They can easily maintain their luminance for 90% of their life and still emit 80% at the end of their life.

Disadvantages Of HPS Lights

HPS lights are now slowly being replaced with the newest technologies, and LED lights are currently on the top. Here are some significant disadvantages of HPS lights that make them less preferable.

• Poor Color Rendering: HPS lights are surpassed by many other technologies. So it is best to use such lamps where color rendering is not a significant concern.
• Long Warm-Up Cycle: After the ignition of the arc, the metal salts are vaporized. The output light doesn’t reach its peak intensity until all the salt is evaporated. The light gradually transitions from red to a distinctive yellow color.
• Mercury Content & Environmental Risk: The world is now eradicating the use of toxic and hazardous materials and striving towards a green future. HPS contains small amounts of mercury which is harmful to the environment if released from the tubes. You can not dispose of HPS lights for this reason.
• Light Wastage: HPS lights throw light in a 360° direction, which means that approximately 15% of the light goes to waste, rendering this solution inefficient.
• Flickering & Damage: One another disadvantage is that HPS lamps are susceptible to flickering and damage. This increases the maintenance cost and the overall cost.
• Extra Ballast Requirement: HPS lights require ‘ballast’ for a stable operation that supplies a constant current to the fixture. This ballast can be damaged by a continuous process and need immediate replacement.

Applications of HPS lights

Since these lights have the upper hand in efficiency compared to incandescent bulbs and fluorescent and mercury lamps, they are used in energy-efficient applications.

Ideal Functional Scenarios for HPS Lamps

High-pressure sodium bulbs are a go-to lighting choice for large outdoor public spaces like parking lots, streetlights, alongside low-demand indoor spaces where accurate color reproduction does not affect daily function.

For example, neighborhood side roads, highway overpass lighting, and open-air supermarket parking garages rely heavily on HPS lamps; these areas only need consistent bright illumination for safety and navigation, so their low CRI does not create any functional drawbacks. Storage basements and unstaffed back corridor indoor lighting also frequently adopt HPS solutions, as workers do not need to judge fine color differences during routine transit.

HPS lamps deliver powerful high-intensity illumination that covers wide vertical and horizontal ranges, which explains their dominant use in large industrial and logistics facilities.

Factories with tall production bays, bulk storage warehouses, freight shipping yards and container terminals all mount HPS fixtures at heights of 15 feet or higher. These high ceilings require strong far-reaching light to fully cover stacked inventory, loading zones and wide work aisles, and HPS’s strong lumen output cuts down on the total number of lamps needed to light these expansive industrial sites.

Application Restrictions Caused by Yellow Light Spectrum

The distinct warm yellow light emitted by HPS hardware creates strict limits on where these lamps can be installed, narrowing most viable use cases down to basic roadway lighting and general functional outdoor projects only.

Any space that relies on clear, natural color visibility cannot rely on standard HPS lamps: retail storefront facades, park decorative landscape lighting and vehicle inspection lots all rule out unmodified HPS due to its heavy yellow tint, which distorts the true color of surfaces, signage and objects.

Even residential backyard lighting often avoids standard HPS, as the monochromatic yellow glow creates an uninviting visual effect compared to neutral-toned alternatives.

Wattage Selection Rules for HPS Installations

A core practical factor to weigh when specifying HPS lamps is wattage rating, since total lumen brightness directly scales with the lamp’s wattage.

The usable wattage range for any given installation is shaped by three key project variables: local mains supply voltage, the matched ballast model paired with the fixture, and the physical structure of the lamp housing itself. Small neighborhood side street lamps might run 70W HPS units, while major highway arterial lighting or warehouse high-bay mounts often require 250W or 400W high-power HPS models to hit required brightness standards.

Even as energy-efficient LED lighting steadily takes over new construction and renovation projects, HPS lamps remain widely deployed across existing public infrastructure and industrial facilities, with thousands of legacy HPS fixtures still operating in parking lots, industrial yards and municipal road networks worldwide.

One another thing to consider is the wattage of HPS lamps, as the output lumen depends on the wattage. The wattage depends on supply voltage, ballast, and fixture design. HPS lights are still widely used, although they are slowly being replaced by LED lighting.

Special Tips: We advise you not to use HPS lights in applications where lighting precision is required, such as facades, task applications, tourism spots, etc. The color rendering is low, which reduces the visibility at night.

To cater to this problem, some designers and manufacturers have created color-corrected HPS lamps that can go up to CRI 80. Moreover, do not use such lights in places where lights must be frequently switched on and off since HPS lights have long warmup and re-strike times.

All About LED Lights

Now, you may know about the strengths and weaknesses of HPS lights if you have read the last part. Here we will look at another famous light source, i.e., LED lights.

LED lights have revolutionized outdoor decorative lighting. Featuring low power consumption and high brightness output, they have fully replaced traditional incandescent lights. As the world shifts toward eco-friendly solutions, LEDs stand out as the greenest and most efficient lighting option available today.

They are widely adopted for both residential and commercial outdoor applications. Though LEDs come with a higher upfront cost, their long service life and stable performance deliver far greater long-term value.

Before exploring why you should buy these fantastic and long-lasting lights, let’s find out what these are in the first place.

What is LED?

To understand the power of LEDs, you need to know what they are made of. This may sound a little boring, but we will simplify it for you.

LED is short for Light Emitting Diode. Similar to HPS, it features two semiconductor electrodes (anode and cathode) made from silicon and selenium, split into two forms with positive holes and negative electrons respectively. When powered, current travels from anode to cathode and triggers contact between the two semiconductors; the collision of positive holes and negative electrons releases energy as visible light.

With a bit of tweaking in semiconductors and introducing different systems of diodes, other colors can be produced. The indium gallium nitride (InGaN) system creates Cyan, blue, and green colors. LED’s come in a wide variety of colors and intensities, and that is a significant plus point. This increases the application manifolds. That is the beauty of LED, and this wide variation is why they dominate the world now.

Output Properties of LEDs

LEDs, unlike HPS lamps, offer a wide range of color temperatures. This increases their applications and broadens the dynamics of possible results that can be achieved. Using the right color temperature, you can create a certain ambiance and mood for your outdoor or facade lighting project. LEDs can give output in the range of 2700K-6500K, from warm light to daylight.

Advantages of LED Lights

Here we are going to discuss the pros of LED lights. This may help you make up your mind about what to buy for your own home or business.

• Premium Light Quality: There are a vast number of shades and different colors available. They are great for decoration as they are pleasing to the eye.
• Low Maintenance Needs: The circuits are durable, and the plastic they are made from is long-lasting, cost-effective, and hassle-free.
• Exceptional Service Lifespan: LEDs outrun every other light source in terms of longevity. Their life span can be up to 50k hours to 100k hours or even more. Every different light can remain functional for up to 20 to 30% of the time.
• Eco-Friendly Performance: LEDs consume less power overall and emit a very trace amount of infrared light.
• Lower Monthly Energy Costs: Consuming less power affects electricity consumption, saving you a lot on your bills.
• Simple, Affordable Repairs: They have cheap components that can be replaced and fixed readily.
• Unmatched Size & Shape Versatility: Various sizes are another feature, as LEDs come in all shapes and sizes. No other light source can be this versatile.
• Instant Quick Startup: LEDs light up to full brightness the moment you switch them on with no warm-up delay. Unlike slow-start HPS lamps, they work instantly for security, road and motion-sensing outdoor lighting.
• Targeted Even Illumination: The lights are directional and illuminate the area equally and adequately.

Disadvantages of LEDs

With so many advantages, you may wonder if there are any cons to LEDs, and you are right; there are not many disadvantages to these.

• High Upfront Price: The primary thing that poses a problem is their initial cost. The LEDs have been expensive since their arrival. Their cost-effectiveness comes after prolonged use.
• Long-Term Value Offsets Cost: The upfront cost would concern the business owner, but the pros outweigh the cons at any time. As technology advances, this issue may resolve sooner than you might think.

Learn more about the Advantages and Disadvantages of LED Lighting.

Uses of LED lights

When we say LED lights are the most versatile light source globally, we mean it. LED technology has completely changed the light industry. The expansion of its use owes to its flexibility.

Let us explore the excellent application of LEDs, making them perfect for residential use and ideal for business.

1. Computers and electrical appliances have been the first to use the excellent functionalities of LEDs light. Initially, they were confined to circuit boards, but slowly their applications widened.

From traffic lights to smartwatches, they are everywhere.

• LEDs are popular for large areas, big halls, and gymnasiums. They have replaced incandescent and fluorescent lights. The output is on par with fluorescent lights, but power consumption is far lower.
• Façade and architecture lighting is another primary use of LEDs. These lights give the mundane wall a very artistic look. LEDs have entirely altered the art of exterior decor these days.

These LEDs give an aesthetic look, and designers have plenty of room to play around.

• Art galleries also showcase an incredible display of LED lights.
• They are instrumental as Grow Lights. LED grow lights are being used right now for nurturing plants indoors.
• LEDs have significantly influenced the automotive industry. From LED work lights to tractor lights, cars are using LEDs everywhere.

This is similar to the aerospace and maritime industry. From signals to electronic devices, their applications are varied.

• Perhaps the most influential application is a LED screen. This technology forever changes the television and the display screens. The size of screens is reduced significantly as well as their cost.
• LEDs are best for landscape lighting. They are much safer than fluorescent and incandescent lights.

Since they produce less heat, they are environmentally friendly, and landscapes are often lit all night, making them a reliable and safe option.

• LEDs can tackle harsh outdoor environments. They are made from a sturdier material that lasts longer in wind and rain. They are resistant to breakage, previously a problem with glass lights.

Comparison Chart

We have summarized all the features (mentioned above in detail) in the chart below.

Frequently Asked Questions

Conclusion

Businesses are all about investing in the right place. LEDs have a higher initial cost than HPS lights, but considering the long-term advantages, we suggest you go for an LED lighting solution. LEDs offer a more comprehensive range of output colors, functionality, and dynamic results. Moreover, they are eco-friendly and require minimum maintenance.

RC Lighting is a LED landscape lighting and LED facade lighting manufacturer in China. We provide a one-stop solution for your projects. Contact us to get a quote for your upcoming projects now!