What Does it Take to Replace 400 Watts Metal Halide with LED?

The right way to replace a Metal Halide is one such extensive topic that continues to be researched by a lot of people time and again. Despite our having detailed the issue in many previous blogs, we still receive a lot of questions, and this time we are going to deal with it all at once.

There are a lot of similarities in the process of replacing a 400-watt metal halide light and a higher-wattage 1,000-watt bulb, but a lot of differences that are worth discussing here.

Customers suffer at the hands of misguided information. Those who are not aware of LEDs may only think of picking an LED based on a perceived notion of the amount of wattage needed. However, this is an inaccurate way to go about replacing metal halide or HPS fixtures. Picking LED bulbs based solely on power or watt is not a good approach.

We are going to share with you our hard-gained wisdom about LED lights that comes after years of experience along with some science-approved advice for your facility on the best way to convert a 400-watt Metal Halide to LED. So, if you have a warehouse, parking lot, gym, manufacturing facility, shop, industrial spaces, or a tennis court, we can show you how easy it is to convert from metal halide and high-pressure sodium fixtures to LED for indoor and outdoor lighting.

If you need the easy way out, then just trust our LED lighting expertise and reach out to us. However, you can even try to do it yourself.

Replacing metal halides with LED fixtures isn’t a complicated process at all and all you need is knowledge about the dos and don’ts of it. Equally important is to go to the right place – we’re here to help.

Gym After Converting To Led

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How Many LED Watts Replace a 400 Watt Metal Halide?

We think that it would be a waste of time to give you generic advice. However, we think that you must know the primary fact that LEDs should never be purchased based on watts.

And buying a 400-watt LED to replace a 400-watt Metal Halide is complete overkill. And even buying an LED light based on the watts of another LED fixture is not advised. The reason is LEDs do not have all the same efficacies.

LEDs can produce the same number of visible lumens while consuming fewer watts than other traditional sources of light. We advise you to focus on the lumens of the light you need. The more energy efficient LED lights will use less energy to produce these lumens.

What Does Lumens Refer To?

You may not know about lumens at all if you have been using light sources like metal halide and HPS. This is because these traditional light sources don’t use these measurement metrics. The light strength of these traditional bulbs is measured based on wattage, which is not the case with LEDs. LEDs use the Lumen metric.


A Lumen is the light measurement metric that denotes the amount of light generated by a light fixture or bulb. These light lumens are produced when the fixtures convert electricity to light. This may prompt you to relate wattages with lumens – but that’s not the right thing to do. LED lights do much better than traditional light fixtures at producing light efficiently. This is why we tell you to replace your metal halides with LEDs using lumens and not watts.

Foot Candle

A foot candle refers to one lumen per square foot and measures light intensity. A lighting plan is performed to generate data on the foot candles and quantity of light for any particular area by assessing the input values of light sources through advanced lighting software.

Further, the software calculates the total amount of light at any given spot produced by all the lights that might affect that area.

Lighting Plan

A lighting plan makes planning a conversion to LED simple.

It helps you make calculated decisions according to the expected light results rather than making random guesses about the right wattage.

A lighting plan shows a graphical, visual report of foot candles throughout the space as well as measurements of lighting balance. 

Finally, you want to think about the lumens needed to replace light fixtures. Watts consumed is the wrong measurement basis.

Quality of Light

We have talked in length about deciding the lumen output quantities of various light fixtures. Let us now discuss the quality of light. The scale used to measure the quality of lumens is called Color Rendering Index or CRI.

Usually, a LED bulb has higher lumen CRI ratings than metal halides or other fixtures. Thus, whenever you decide to replace your metal halide light fixtures with LED lights, you will be selecting the LEDs with lesser lumens. It has often been noted that LEDs with lesser lumens, say 20,000, appear brighter than any metal halide light that produces 30,000+ lumens.

The CRI or Color Rendering Index measures the quality of the light emitted by any light source. The concept is quite complex to understand but to put it simply, it measures how close light quality can be to the ultimate light source, the sun.

Higher CRI Means Lesser Lumens Required

Parkinglot 1
Coca Cola Warehouse 150w High Bay2

In a metal halide fixture with 30000 initial lumens, a lumen loss due to reflection can cause the effective lumen output to drop to 21000 lumens.

400 Watt Metal Halide Initial Lumens and L70

As an example, let’s use a Metal Halide that produces 30,000 lumens. This bulb, out of the box, produces high initial light output. But then its lumens start to depreciate rapidly. It loses about 50% lumens at half-life, and it lasts for about 15,000 hours. This means it loses nearly 15,000 lumens by the time it runs for 7500 hours.

Regarding L70, this term denotes the total hours any light fixture remains lit before its lumen output rate is reduced to 70% of initial lumens. The L70 value of metal halides is 5000 hours. This also points out the fact that right after the metal halides are put into use, their light starts to lose quality and brightness very rapidly.

The Reflection of Light Inside the Fixture Reduces Its Lumen Output

One of the many factors that play a determining role in the setting of the right lumen amount for the replacement of any 400-watt metal halide is reflection. LED lights utilize directional lighting which directs their lumens to fall on a pre-set point. They don’t need any support like a reflector to deliver the rays at a fixed point.

The opposite is the case with traditional lights that have omnidirectional lighting and need reflectors to focus and cast their light. However, in this process, loss of lumens happens with every reflected ray of light that bounces more than once off the reflector. Studies have shown that a lumen loss of about 30% can happen in such a reflective process.

Comparing Photopic and Scotopic Lumens

Photopic and scotopic lumens are terms used for the different ways used by a light meter and us respectively to observe any light. Photopic lumens are detected by devices like light meters or cameras while Scotopic lumens are visible to the naked eye as well.

Light rays like IR or UV emitted by light sources remain invisible to us. They are of no use to us but can be detected and read by light meters as output.

LED lights mark a contrast with most other light sources by producing light of the visible spectrum only. This means that LEDs will give a brighter light that is visible too despite having the same lumen value as any metal halide light fixture.


Cones and Photopic Vision

The central part of the eye is the fovea that is rich in a type of cells called “Cones”. Cones are responsible for color vision and are involved in vision during bright light. This is called Photopic vision.

Rods and Scotopic Vision

Rods are sensitive to dim light and are active during low light intensity conditions, such as night. Rods cannot perceive color. Vision that comes from rods is “black and white”.

Measuring Instruments Measure Light Intensity in Lumens

Lighting Instruments is similar to the response of comes. Thus, the lumens measured by a light meter are also called Photopic Lumens.

Genesis Products Warehouse Onsrud 57 Foot Candles Mllg Al Led Hblin5 220 50
Led Hb3 200

Easily Convert from Metal Halide to LED – Create a Lighting Plan

LED Lighting Supply has been providing thousands of free lighting plans for customers looking to convert from Metal Halide to LED.

Whether you need a free lighting plan or have questions about LEDs, our expert lighting team will help you make the right choice – whether that’s for a school gym or a 1,000,000-square-foot facility.

Contact us for a free lighting plan or to discuss your LED lighting goals.

Warehouse Lighting Plan

Dwayne Kula

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About the Author

Dwayne Kula is President of LED Lighting Supply. On any given day, Dwayne is writing content for the site and helps manage the marketing initiatives that are on-going. He has a Software Engineering degree and still dabbles in writing software for the company as needed. When not working, he enjoys spending time with his family, working out, playing the occasional game of golf and exploring New England.

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