Energy Saving

Energy-saving Lighting 

As we sell luminaires/lighting fixtures and they consume high-quality electrical energy, we feel responsible for ensuring that customers/end-users are informed about the efficient use of luminaires and lighting fixtures, and we want to contribute to raising awareness.

Our practical tips for energy savings in lighting/luminaires include the most important information/facts about the current state of technology and provide information on important technical terms.

Definition of Lamp and Luminaire:

First, the difference between a lamp and a luminaire* should be clarified. "Lamp" refers to the technical design of an artificial light source. The lamp converts electrical energy into light. The lamp is inserted into the luminaire, which distributes, directs, and protects the light from the lamp against glare.

*We frequently use the word "lamp" in our product descriptions because it is more logical or more commonly used and searched for in certain contexts, making it easier to find.

Lamps come in many different types. They differ in terms of the method of light generation, their geometric shape, and their photometric properties. In residential areas, for example, halogen lamps, compact fluorescent lamps, and fluorescent lamps are used. The lamp is the light source. And without a lamp, there is no light.

Types of Lamps:

Today, there are energy-efficient and long-lasting lamps available for every lighting task. They differ in terms of:

  • the method of light generation
  • their photometric properties
  • their power consumption in watts
  • their geometric design

While the Edison incandescent lamp is the prototype of all electric light sources, it has two significant disadvantages: it produces much more heat than light, and it has a short lifespan of a maximum of 1.000 operating hours. However, there are now new light sources that operate much more energy-efficiently and have a longer lifespan.

Energy Saving with Lighting - What's the Real Story?

Compared to a traditional incandescent bulb, an energy-saving lamp consumes 75% - 80% less energy. This means that a 75-watt incandescent bulb can be replaced by a 15-watt energy-saving lamp. The additional costs for the environmentally friendly lamp pay off through its longer lifespan and the saved electricity costs: while an incandescent bulb lasts only a maximum of 1,000 hours, an energy-saving lamp can last for 6,000 - 15,000 operating hours. However, this does not mean that the environmental balance of an energy-saving lamp must necessarily be better than that of an Edison incandescent bulb, as the production effort and disposal need to be considered. However, this can vary significantly from manufacturer to manufacturer and from product to product.

According to the latest survey by the Energy Agency NRW, the energy consumption of lighting in private household’s accounts for 9.7% of the total electricity consumption, ranking it 5th (based on the evaluation of 380,370 households in Germany in 2011). However, calculations of energy consumption should not be based on a fixed 10% of the total electricity consumption but should be compared to the existing light sources, their operating hours, and their consumption in order to obtain meaningful results. Energy-saving light sources include compact fluorescent lamps, light-emitting diodes (LEDs), or coated halogen lamps. All types of energy-saving light sources have in common that their technical development is not yet complete - unlike conventional incandescent bulbs - and therefore significant improvements can still be expected. The models currently available on the market differ significantly in terms of efficiency, color rendering, and durability. Regarding these quality characteristics, it can be assumed that products from reputable manufacturers such as Philips, Osram, General Electric, Sylvania, Megaman, etc., are the most advanced.

Types of Light Sources:

The most controversial type of efficient light sources (ESL: Energy-Saving Lamps) is the compact fluorescent lamp, which belongs to the group of fluorescent lamps and represents a low-pressure mercury vapor lamp. The development of this type of lamp is largely completed.

Advantages: Today, the efficiency of compact fluorescent lamps is about 50 to 70 lumens per watt, which means about 80% savings compared to normal incandescent bulbs. The lifespan is usually between 6,000 and 15,000 hours, although many types respond to frequent switching cycles with significantly reduced durability. ESLs always contain a ballast. The danger associated with the magnetic waves of the ESL's ballast, and the resulting health risks, have not been proven. The radiation emitted by the ballast (also known as transformer or driver) does not differ from the radiation emitted by chargers, power supplies, etc., of other devices. Disadvantages: Compact fluorescent lamps contain toxic mercury and therefore require complex disposal procedures. Breaking the lamp should be avoided at all costs. As a precaution, lamps with an amalgam coating instead of mercury or lamps with double envelopes should be chosen. There are differences in terms of breakage safety between manufacturers. ESLs are very sensitive to short switching cycles. A clear glass envelope is technically not possible. Another disadvantage (the health effects are controversial) is the one-sided color rendering. Depending on the light color, the color rendering can be one-sided and unnatural. Cheap products, due to their low color rendering index when used incorrectly or frequently, are said to cause sleep problems, dullness, and concentration problems.

Halogen lamps are usually 25% more energy-efficient than regular incandescent bulbs, but very good models can save up to 50%. The lifespan is usually between 2.000-3.000 hours, which is shorter than other energy-efficient light sources but longer than that of traditional incandescent bulbs. Advantages: In general, these light sources are dimmable and have low sensitivity to dimming processes. They have good color rendering, and the light appears very natural and similar to natural sunlight. Halogen lamps, with a few exceptions, do not need to be disposed of separately and can be thrown in the regular waste. A disadvantage is the relatively high heat generation and the limited energy savings.

Metal halide lamps have no commonalities with halogen lamps, which are incandescent lamps, except for the similar name. They have a very high color rendering index and are used, for example, for daylight-like lighting of shop windows, etc. Their high price, the complex technology required to operate the lamps, and the long warm-up time (about 1-5 minutes) make the lamps uninteresting for household use. These lamps are still widely used for plant lighting.

LED (Light-Emitting Diodes) are a relatively new and evolving form of lighting and are playing an increasingly important role in residential lighting. LEDs with an efficiency of over 200 lumens per watt are now available on the market. The average lifespan of LED lamps can range from 15.000 to 50.000 operating hours, depending on the type and application. These are their main advantages. Additional advantages include the now excellent color rendering index (CRI>90) for good quality branded products and low heat generation. The disadvantages lie in the still relatively high initial cost, complex technology, complex manufacturing process, and significant variations in quality. Since LED lamps are still in the midst of development, the disadvantages are expected to be mitigated in the near future. When purchasing LED products, it is important to carefully check the technical specifications of the lamps.

OLEDs (Organic Light-Emitting Diodes) are a relatively new form of lighting and are still in an early development phase in the lighting sector. Their most significant advantages so far are high light output and a more cost-effective production compared to LEDs. However, LEDs have not yet reached their limits in this regard. Another advantage is that they can be applied in thin organic layers and can be bent (using different production methods). This can create new possibilities in the production of lamps and luminaires. The biggest drawback so far is their very short lifespan and the rapid reduction in luminosity after a short period of time. Currently, OLEDs are mainly used in displays, but there are already some products available for decorative lighting. In the field of architecture and projects, there are already some examples of large-scale OLED lighting or specialized lighting.

Power Consumption and Lumen of a Light Source:

The following comparison table provides an overview of the light output of various types of light sources at the same power consumption. The power consumption of an LED lamp or ESL can vary; here, average values have been used.

Energy-Saving Lamps:Halogen Lamps:LED Lamps:Watt (Consumption)
125 Lumen120 Lumen1800 Lumen15W
230 Lumen220 Lumen3000 Lumen25W
430 Lumen400 Lumen4800 Lumen40W
740 Lumen700 Lumen7200 Lumen60W
980 Lumen920 Lumen9000 Lumen75W
1400 Lumen1330 Lumen11.000 Lumen100W
2260 Lumen2140 Lumen16.000 Lumen150W
3250 Lumen3000 Lumen20.000 Lumen200W

According to an EU decision, most traditional incandescent bulbs are gradually being phased out, and households will need to meet their replacement needs with energy-saving lamps or LED lamps. The EU aims to save around 15.5 million tons of carbon dioxide per year in its member states by 2020. Whether the strong promotion of ESL has contributed to or will contribute to this goal is a matter of debate due to the high environmental impact.

In general, the following criteria should be considered when using/replacing light sources:

Pay attention to the Energy Efficiency Label (EEL), which ranges from Class A to G.
Compact fluorescent lamps are classified in classes A or B.
Normal incandescent bulbs usually only reach Class E

Which light source is the best - and where?

This paragraph can be relativized. Use ESL lamps only when necessary, otherwise use LED lamps. For the sake of completeness, we will keep this paragraph online: Preferably use compact fluorescent lamps in places where they have a long to very long operating time. The principle here is: the longer the operating time and the fewer switching cycles, the greater the savings and the lifespan of the lamps. These lamps can be dimmed using pulse width modulation. ESL lamps with an integrated ballast (all E14 and E27 models) can only be dimmed if the lamp allows it. With ESL lamps with a separate ballast (e.g., T5 tubes), dimming is controlled by the ballast of the luminaire, which means that the luminaire (specifically its ballast) must be dimmable, and the lamp itself has no influence on it.

High-quality energy-saving lamps have a preheating function that prevents damage from frequent switching on and off.

Note: Based on an average lifespan of 15,000 hours for this type of lamp and assumed electricity costs of 18 cents/kWh, you can save according to the example below:

ESL:       Incandescent Lamp:      Savings:

5W         25W                 54,00€
9W         40W                 83,00€
11W       60W                132,00
15W       75W                162,00
20W      100W               216,00
23W      120W               261,00

Halogen lamps should be used in places where a lot of flicker-free light, good color rendering, and dimmability are desired. However, strong dimming significantly reduces their lifespan.

LED lamps have the greatest potential in terms of energy savings, light output, and versatility. Manufacturers announce increasingly higher light outputs in shorter periods of time, and LED lamps with a high color rendering index are now quite common. Note that LED lamps are subject to thermal limits. For the standard E27 base, there are hardly any lamps available above 17 watts of power consumption that may or should be used in enclosed spaces. Good cooling of the LED lamp contributes to a longer lifespan. LED lamps (and luminaires) can now be used almost anywhere, although specialized solutions can be expensive.

Nearly all reputable luminaire manufacturers now offer luminaires with LED lamps in their product range. In principle, LEDs can be dimmed quite well using pulse width modulation. Whether this is possible with a specific lamp depends on the ballast used.

LED lamps represent the next stage of evolution in the lighting industry and have a range of advantages over conventional or energy-saving lamps. In addition to significantly longer lifespan and much lower heat generation, LEDs can be operated in a more environmentally friendly manner due to their significantly lower energy consumption, contributing to a reduction in CO2 emissions.

Due to their small size and extremely compact light-emitting diodes, much more flexible and architecturally impressive lighting installations can be realized.

Important Keywords Related to Light:

  • Lux, lumen, and candela are units used to describe light intensity.
  • Lux: Lux is the SI unit of the derived quantity illuminance and the corresponding emitter size, specific light emission.
  • Candela: Candela is the photometric SI base unit of luminous intensity
  • Lumen: Lumen is the photometric unit of luminous flux, which is a more meaningful measure of the amount of light emitted by a light source. To calculate the efficiency of a lamp, you simply divide lumens by watts (lm/W), resulting in the ratio of luminous flux to power consumed.
  • 350 lumens is approximately equivalent to a 7-watt energy-saving lamp. 415 lumens is approximately equivalent to a traditional 40-watt incandescent bulb. 710 lumens is approximately equivalent to a traditional 60-watt incandescent bulb.
  • Illuminance, measured in lux, can be converted to luminous flux and luminous intensity.
  • The color of "white" light is indicated in degrees Kelvin*.

Kelvin*: The Kelvin is the SI base unit of thermodynamic temperature. Warm white light, for example, has a color temperature of approximately 3000K. Neutral white light has a color temperature of approximately 4500K. Cool white light has a color temperature of approximately 6500K. In the commercial sector, LEDs with 2700 Kelvin are referred to as warm white, LEDs with 3000 Kelvin as neutral white, and LEDs with 3500-4000 Kelvin as cool white. These three ranges are also the most commonly used color temperatures in white light. Some manufacturers now offer the ability to adjust the color (e.g., from 2500-3750K). This has nothing to do with RGB LEDs.

The color of "colored" light is indicated in nanometers. Wavelength Color Tone:

  • Violet: 380–420 nm
  • Blue: 420–490 nm
  • Green: 490–575 nm
  • Yellow: 575–585 nm
  • Orange: 585–650 nm
  • Red: 650–750 nm

What are RGB LEDs?

LEDs that can change between these colors are called RGB LEDs. RGB stands for red, green, blue. With these three primary colors, virtually any color can be created. However, in terms of light output, RGB LEDs generally fall far behind the lumens/watt performance of white LEDs. To control such RGB LEDs, a compatible ballast and control unit are required to initiate color changes. These control units can be programmed, controlled via remote control, or may include more complex functions. Inexpensive finished products usually have limited functions.

What does color rendering mean?

CRI: Color Rendering Index, is a photometric quantity that describes the quality of color rendering for light sources with the same correlated color temperature. A CRI property above 80 can be considered good, while CRI above 90 is excellent. This index is particularly important for ESL and LED lamps.

Calculation Example for Power Consumption Savings:

Here's an example calculation for replacing light sources:

Important - When replacing ordinary light sources with LED light sources, keep in mind that they will last a very long time. To operate them happily for many years, it is advisable to use high-quality light sources to avoid the need for replacement soon with higher-quality models, which would be an unnecessary additional investment.

For a very simple calculation of consumption and the associated cost savings of a replacement, you need the following variables (filled in with example values):

  • Light source consumption (e.g., 40W incandescent bulb): 40 watts
  • Quantity of light sources: 5
  • Electricity price: 0.20€/kWh (kWh = kilowatt-hour, 1 kilowatt is 1000W)
  • Average daily operating time: 4 hours

Using these values, the calculation is as follows: 40W x 5 x 4h (resulting in a consumption of 800W/day, or 0.8 kilowatts expressed in kilowatt-hours (kWh) would be 0.2 kWh x 4).

By multiplying this value by the electricity price, you obtain the daily cost. In our case, 0.8 x 0.2 equals 0.16. Annually (365 days), this amounts to 58.40€.

Reversing the calculation with LED light sources:

  • Light source consumption: 7W
  • Quantity of light sources: 5
  • Electricity price: 0.2€/kWh
  • Average daily operating time: 4 hours

7x5x4 = 140W which is 0,14KW - resulting in 0,028€ / day - or 10,22€ / year. Saving 48,18€.

The cost of purchasing 4xE27 7W LED light sources (for example) is 36.00€. After just one year, the light sources have already paid for themselves. Note that ordinary light sources need to be replaced annually (1.46 per year with an operating time of 1000 hours and 4 hours/day), resulting in an additional savings of 9.34€ per year with a light source cost of 1.60€. In certain light source configurations, this additional savings can be an important factor.

For a realistic calculation example, the value needs to be calculated separately for each light source with different consumption and operating time.