How Many Watts,Lumen,Electricity Cost Should Street Light Be

The street light brings us light in the dark. With the improvement of living standards, more and more outdoor road street lights are installed. Street lights can not only reduce safety accidents, but also facilitate us to travel at night. Some street lights combined with modern aesthetic design also create urban beautiful landscapes. Do you want to install new street lights or retrofit old  lights to LED? So,what light is best for street light?

Have you found that the familiar orange-yellow street lights are slowly diminishing and turning into brighter, whiter LED street lights. Nevertheless, due to different budget and consideration, some people may still want to install high-pressure sodium lamps. It’s also okay.

In this article, we will introduce how many watts of street lights (including LED and high-pressure sodium lamps) do I need, how many lumens of street lights do I need, and how to calculate of electricity costs.

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How many watts should a HPS street light be

In general,the watts of HPS street lights is about 150W-400W.

The power depends on the requirement of the road.A 250W street light are used for light pole below 8 meters, A 400W high-pressure sodium light are used for light pole above 8 meters.

For the first-level main road, requires high pressure sodium lamps above 400W to 1000W (main road) and 150W high pressure sodium lamps for branch roads.A 110W sodium lamps are commonly used in parks and gardens, especially suitable for places where the light intensity is not high.

How many watts should a LED street light be

How to determine the wattage of the LED street light? The wattage of the LED street light is related to many factors, such as a main road or a branch road, a courtyard or a public road,and pole height etc.

The power of LED street lights be determined according to the different conditions of the road. In general, 6 meters requires 30W~60W, 8 meters requires 60W~100W, professional LED street light manufacturers will estimate the road conditions, then they give you a good solution.

Why use LED street lights

The theoretical life of the led street is very long, but the overall lifespan of a light fixture system is not the life of the light source,because the light fixture also includes the lifespan of the driver and the lens. Therefore, the shortest element of the light fixture will ultimately determine the life of the entire system.At present, the lifespan of the good driving power supply and the lens made of silicon material is up to 50,000 hours.

Energy saving is one of the biggest advantages of using LED lamps.

For example,if we replace of 250W high pressure sodium  light with 120W LED.

The actual power of the high-pressure sodium light needs to be multiplied by 1.17 due to adding the ballast.While the entire power of the LED light = light source power + power loss, the current driving efficiency of LEDs is about 97%.So,

  1. The actual power of HPS light is 292.5W=250W*1.17(Note:only the lower value in theory)
  2. The actual power of LED light is 123.6W= 120*1.1.03

Taking 100 street light run for 12 hours per day as an example:

  1. The power consumption of high-pressure sodium light = 292.5*100/1000*12=351Kwh
  2. The power consumption of LED streey light =123.6*100/1000*12=148Kwh.

If we add the intelligent dimming of LED street lights, the overall energy saving rate is also improving.

How to choose the wattage of LED street light

The wattage of LED street lights is determined according to the width of the road and the height of the light pole or the road lighting conditions etc :

Height of pole

The wattage of the LED street light is closely related to the height of the light pole. Under the same conditions, the higher the light pole, the higher the wattage of the LED, etc., if you choose a small wattage LED street light, it is likely to bring the risk of insufficient brightness .

Road width

If there is a narrow road, please refer to the appropriate light pole height standard but if the road is wide,it needs to increase the wattage of the LED light appropriately.

Installation Environment

Even under the same height of light pole conditions, different roads require different brightness standards. For example, the main road requires higher brightness than branch roads. Similarly, the brightness of urban roads is higher than that of rural areas because there are fewer vehicles and pedestrians in rural areas. Too bright, not only high cost, but also waste of energy. If the main road of the city is not bright enough, it may cause a safety accident.

According to experience, the commonly used LED street light  wattage like below:

WattagePole heightRoad width
20W5/6m6-8/8-12m(2 lanes)
30W-50W6m-7m8-10m(2 lanes)
60W7m-8m10-15m(3 lanes)
80W8m0-15m(3 lanes)

Note:the above table is only for reference.

How Many Lumens is a Street Light?

Generally speaking, the output of high-pressure sodium light is about 80-140LM/W, and we take the intermediate value of 120LM/W, so a 100W HPS street light is 12,000 lumens, a 250W street light is 30,000 lumens, and a 400W street light is about 48,000 lumens But it is only the theory lumen. In practical applications, we also need to consider the light efficiency of 50%-70%.

According to the above wattage conversion,A 250W high pressure sodium lamps are used on poles below 8 meters, that is 30,000 lumens.A 400W HPS light are used on poles above 8 meters,that is 48,000. lumens. and A 110W HPS light is commonly used in parks and gardens,that is about 13,000lumen.

What is the lumen of a 100W LED street light?

It is difficult to provide a accurate answer for 100W LED street lights, because there are many different factors such as LED  efficiency, power efficiency, lens efficiency, heat dissipation conditions, etc. However, the luminous efficiency of LEDs is 60-120LM/W, so 100W LED lumens are between 6000-12000 lumen.

How much electricity does a street light use per day

The electricity cost of street light depends on different factors, such as the type of light fixture, the power of the light, the number of light, and the working time.

If a 1Km long two-lane road,with a light pole distance of 40m, using 100W LED street light runs for 12 hours a day, and the electricity cost is 0.1USD KW/h:

So,the daily cost is:50*100*0.1*12/1000=6 USD

If you use a traditional metal halide or high pressure sodium lamp, you need a 400W lamp equivalent to 100W LED.

So,the daily cost is:50*400*0.1*12/1000=24USD

Through the above comparison, LED lights can save energy consumption very significantly. Although the initial investment cost is high, the longer the operation time, the lower the electricity consumption.

If you use LED street light that can be automatically dimmed or LED solar street lights, you will further reduce your daily power consumption and electricity costs.

This is an outdoor solar sensor street light(sensor connector from Shine indystry-one of sealed connector manufaturers), which can be controlled by remote control.It has heat resistance and IP65 Waterproof function can fully protect circuit and rechargeable battery, and also withstand bad weather in a long time.

Wrapping up

In this article, we have introduced that the wattage of street lamps is closely related to the type of light, the height of the light poles, the road width and the installation environment,how many lumen of street light should be, and how to calculate the power consumption costs of street light per day. The above is only for reference. If you need street light solution, please free contact us for more help.