Lumen is a unit of measure for illumination. What are lumens and how to convert them to watts? What is lumen in car lighting

There are many myths around the concept of "lumen", therefore, in order to dispel some of them, consider the most frequently asked questions, such as: how many lumens are in an incandescent lamp, in an LED lamp, how many lumens does a 1W LED lamp contain, how to determine its luminous flux , and which LED lamps are similar to incandescent lamps.

To begin with, let's figure out what the concept of "lumen" means. A lumen is a unit of measure for the amount of light emitted from a light source, which can be an incandescent lamp, LED lamp, LED, or other lighting fixture.

To make it easier to conduct a comparative analysis, you can refer to the table, which shows the ratio of SP (lumens) to the power of the lighting device (W) for incandescent, fluorescent and LED lamps. Based on these data, it can be seen that LED lamps are 10 times more efficient than incandescent lamps, and 2 times more efficient than fluorescent lamps. In addition, unlike fluorescent lamps and incandescent lamps, the LED lamp, and therefore the LED, emits directional light, from which it can be concluded that the illumination from the LED lamp will be much higher. Therefore, using an LED street lamp as lighting, you can achieve much better illumination than when using other lamps.

As for the number of lumens in a 1W LED lamp.

For LEDs, the luminous flux ranges from 80 to 150 lm out of 1 watt. This is due to some differences in the current-voltage characteristics of LEDs and cooling systems. The luminous flux of experimental LEDs reaches 220 lm / W, but such LEDs are not found in mass production.

How can you determine the number of lumens in a lamp or light bulb.

Usually this information is indicated on the packaging or in the instructions for the product, but tabular data can also be used.
To independently determine lumens, you need a luxmeter that determines the level of illumination in each area of ​​\u200b\u200bthe room. Lux in this case is the quantitative ratio of lumens to the area of ​​illumination (1lux-1lumen per m2). With the intensity of light coming from an isotropic source equal to 1 candela, the total luminous flux is 4

You will learn about this by reading the article below.

Lumen (lm, lm) - a unit of measurement of luminous flux in the system of calculations (SI).

One lumen is equal to the luminous flux emitted by a point isotropic source, with a luminous intensity equal to one candela, into a solid angle of one steradian (1 lm = 1 cd sr). The total luminous flux created by an isotropic source, with a luminous intensity of one candela, is equal to 4 lumens.

A typical 100 W incandescent lamp produces a luminous flux of approximately 1300 lm. The 26 W compact fluorescent lamp produces a luminous flux of approx. 1600 lm.

Lumen - Total luminous flux from a source. However, this measurement usually does not take into account the focusing efficiency of a reflector or lens and is therefore not a direct measure of the brightness or useful beam output of a flashlight. A wide beam of light can have the same lumens as a narrow beam. Lumens cannot be used to determine the intensity of a beam, because the lumen rating includes all of the scattered, useless light.

Lux (symbol: lux, lx) is a unit of measurement of illumination in the SI system.

Lux is equal to the illumination of a surface with an area of ​​1 m² with a luminous flux of radiation falling on it, equal to 1 lumen.

100 lumens were collected and projected onto a 1 meter square area.

Illumination of the area will be 100 lux.

The same 100 lumens directed at 10 square meters will give an illumination of 10 lux.

Candela (symbol: cd, cd) - one of the seven basic units of measurement of the SI system, is equal to the intensity of light emitted in a given direction by a source of monochromatic radiation with a frequency of 540 1012 hertz, the energy intensity of which in this direction is (1/683) W / cf.

The selected frequency is green. The human eye is most sensitive in this region of the spectrum. If the radiation has a different frequency, then a greater energy intensity is required to achieve the same light intensity.

Previously, the candela was defined as the intensity of light emitted by a black body perpendicular to a surface of 1/60 cm? at the melting point of platinum (2042.5 K). In the modern definition, the factor 1/683 is chosen so that the new definition matches the old one.

The strength of light emitted by a candle is approximately equal to one candela (Latin candela - candle), so this unit of measurement used to be called a “candle”, now this name is obsolete and is not used.

In Soviet times, when choosing a light bulb, consumers were guided by the number of watts in it. The more of them - the brighter this device shone. However, today (when many new varieties of lamps have appeared on store shelves), we increasingly come across such a concept as “lumen”. What is it, how does it differ from a watt, and what is the unit called lumen per watt? Let's find the answers to these questions.

What is "lumen"

In the middle of the twentieth century. to avoid confusion in units of measurement between different countries, the universal SI system was introduced. It is thanks to her that we have watts, amperes, meters, kilograms, etc.

According to it, (visible electromagnetic radiation) is. In fact, these units measure the amount of light emanating from its source.

Also, to the question of what “lumen” is, you can answer that this is the name of a famous Russian rock band from Ufa. Having started its activity in 1998, for almost twenty years it continues to be loved by many listeners in the Russian Federation and abroad.

Origin of the word

Having learned what a lumen is, it is worth clarifying where this word came from in the Russian language.

Like most of the names of units of measurement in the SI system, the term in question is Latinism. It is derived from the word for "light" (lūmen).

At the same time, some linguists argue that the noun could also be formed from the Proto-Indo-European word leuk (white) or from lucmen (the meaning is not exactly established).

What is the difference between lumen and lux

Considering the meaning of the word "lumen", it is worth mentioning such a concept close to it as "lux".

Both of these terms refer to light energy units, however, lumens is all the light emitted by the source, and lux is the amount that reached the illuminated surface, and was not stopped by some kind of obstacles with the formation of shadows.

The interdependence of these units can be reflected in the following formula: 1 lux = 1 lumen / 1 square meter.

For example, if a lamp illuminating an area of ​​1 m 2 emits 50 lumens, then the illumination of this place is 50 lux (50lm / 1m 2 \u003d 50 lux).

However, if the same lamp with the same amount of light is used for a room of 10 m 2, then the illumination in it will be less than in the previous case. Only 5 lux (50lm/10m 2 = 5 lux).

In addition, such calculations did not take into account the presence of various obstacles that prevent the light rays from reaching the surface, which significantly reduces the level of illumination.

In connection with this situation in any country in the world there are lighting standards for various buildings. If it is below them, a person's vision does not receive enough light and deteriorates. For this reason, when planning to make repairs or rearrangements in your home, it is always important to take this nuance into account.

There are also a number of design programs in which such calculations are made automatically.

Lumen and watt

Having learned the difference and meaning of lumen and lux, you should pay attention to another unit of the SI system - watt.

Due to their use for light bulbs, some believe that these units can be freely correlated with each other. However, this is not quite true.

The fact is that in watts the power of energy that a light bulb consumes is measured, and in lumens it is the amount of light that it emits.

During the existence of only incandescent lamps, it was easier to calculate the amount of light from such a device. Since a 100 W light bulb gave out about 1600 lm of light. While a similar device at 60 W - 800 lm. It turned out that the more energy consumed, the better the lighting.

But today it's not like that. In recent decades, several new types of lighting sources have been invented (luminescent, etc.). Their advantage is economy. That is, they shine brighter with less energy used.

In this regard, if necessary, to draw up a relationship between watts and lumens, you need to take into account the type of lamp and look for its luminosity in special tables.

It is worth noting that an ordinary person sometimes does not want to rebuild and understand all these subtleties. Therefore, most domestic manufacturers of new-type light bulbs on the labels indicate not only the number of lumens, but how much less watts this device consumes (compared to an incandescent lamp). For example: a 12 watt lamp produces light as at 75 watts.

The unit of measure "lumens per watt": its meaning and scope

For example, a classic 40 W incandescent lamp has a light output of 10.4 lm/W. At the same time, for an induction lamp with the same power, this figure is much higher - 90 lm / W.

For this reason, when choosing a lighting device for your home, you should still not be too lazy, but find out the level of its light output. As a rule, such data is on the labels.

Understanding the technical features and numerous characteristics can be difficult even for an experienced consumer.

The following questions are common regarding LED lamps:

• What is the analogue of a 100-watt incandescent lamp?
• How is the luminous flux of a lamp determined?
• How many lumens are in a light bulb?
• How to choose an LED analogue to incandescent lamps?
• How many lumens are there in 1 watt of LED light bulb?

Check out the Lumens (Lm) to Watts (W) ratio table for an incandescent lamp in relation to an LED lamp:

How many lumens in 1 watt LED light bulb?

In LEDs, the luminous flux varies depending on the manufacturer, quality and voltage. Average values ​​for 1 W are 80-150 lm. If you increase the voltage of the LED, the luminous flux will also increase, but this also entails an increase in the temperature released. To reduce the temperature, various cooling methods are used using radiators and cooling systems.

What is a lumen?

Lumens measure the luminous flux of a light source.

How to determine the number of lumens in a light bulb?

First, you need to study the product box or product specification for the specified luminous flux. If the information is not listed, you can find a similar product from a well-known manufacturer to compare specifications.

It is also possible to determine how many lumens in your light bulb yourself using a light meter. Lux refers to the ratio of the number of lumens to the illuminated area (1 Lx = 1 Lm / sq.m). You need to know the manufacturer's declared illumination for a particular LED lamp.

In practice, the indicator of illumination on the working surface, measured in lux, is of primary importance. Compliance with the illumination of work surfaces and premises for different areas of activity is determined by state standards prescribed in SNiP 05/23/2010.

How many lumens are LEDs in relation to other light sources?

• LN - incandescent lamp,
• GLN - halogen lamp,
• LL - fluorescent lamp,
• CFL - compact fluorescent lamp,
• MHL - metal halide lamp.
• DRL - arc mercury lamp. High pressure mercury vapor lamps. Used for general lighting of industrial premises and open spaces.

Light output can be reduced by up to 40 percent due to reflection losses, depending on the luminaire body and diffuser shape when using DRL in luminaires.

When choosing an LED lamp, pay attention to the lumens to make sure you get the amount of light you need.

Usually we buy things based on the quantity we need, don't we? When we buy milk, we buy it in liters. Then why should light be different? For decades, we've bought light bulbs based on how much energy they use (watts) and not how much light they give us (lumens).

Lumen measures how much light you get from a light bulb. The more lumens, the brighter the light. Fewer lumens produce less light.

But the brightness and number of lumens can vary greatly, so there is a certain way to calculate the appropriate characteristics.

Practical calculation method:

• to replace a 100-watt incandescent bulb, look for an LED light bulb that will give 1100 lumens;
• 75-watt lamp - about 750 lumens;
• 60-watt lamp - about 550 lumens;
• A 40-watt lamp is about 200 lumens.

If you want something less bright, get LED bulbs with lower lumens.

Lighting Efficiency:

But we must not forget that Lumen is the total luminous flux from the source. However, this measurement does not usually take into account the focusing efficiency of a reflector or lens and is therefore not a direct parameter for evaluating the brightness or useful beam performance of a luminaire. A wide beam of light can have the same lumens as a narrow beam. Lumens cannot be used to determine the intensity of a beam because the lumen rating includes all stray and useless light.

Lux is a unit of measure for illuminance.

For example, 1 Lux is equal to the illumination of a surface with an area of ​​1 m² with a luminous flux of radiation incident on it equal to 1 lumen. If you collect 100 lumens and project them onto an area of ​​1 m², then the illumination of this area will be 100 lux. If the same 100 lumens are directed to 10 m², then the illumination will be 10 lux.

Label for LED lamps:

What should be on the packaging when you buy LED lighting products?

To help consumers better understand the transition from watts to lumens, the Federal Trade Commission has proposed a new label for LED bulbs. Such a label will help people buy light bulbs that are right for them.

Just like food labels, a lighting label helps consumers understand what they are really buying. The label clearly indicates: the luminous flux, the type of bulb, the price, the estimated cost of operation for the year and the color of the glow from warm white (with a yellowish tint) to cold white to cold (with a blue tint).