Summarize
- When choosing LED luminaires, consider the colour rendering index, CRI over 90 recommended
- Dimming feature important, ensure compatibility with dimmer
- The colour of light affects the mood, check the kelvin value before buying
- The amount of light is measured in lumens, not watts as before
- High-quality frame material, such as aluminium, extends the life of the LED
LED luminaires are energy-efficient and good for lighting homes, offices and other spaces. When comparing efficiency and LED prices, you may make a mistake if you don’t know a few basics. We’ve put together a 10-point list to help you avoid making bad choices when buying LED lighting. In a nutshell, you should focus on the following: colour rendering index, dimming, light colour, luminous flux, lamp body material, power supply, installation method, warranty, point of sale and sales photos.
1. High enough colour rendering index – CRI
Incandescent light bulbs always have a high colour rendering index, which means that the light from an incandescent bulb makes the colours in the environment look as they should. In the case of light produced with LED technology, the colour rendering index must be taken into account, as there are many products in the LED lighting sector that make the ambient colours appear bluish, greyish or greenish. This is because the colour rendering index (CRI) is too low. CRI is different from Ra, as Ra leaves some of the colours in the colour gamut unmeasured. For general lighting and task lighting in areas with high occupancy, we recommend buying luminaires with a CRI greater than 90. The long-standing Ra < 80 recommendations in Finland for high quality LEDs have been passed by years ago. If the CRI is not mentioned at all, it may not be a LED luminaire with very good colour rendering.
2. Dimming feature and compatible dimmer
Dimming LED lamps and bulbs is also a degree more difficult than dimming incandescent or halogen lamps, for example, because of differences in dimming techniques between LEDs. Since a good quality LED luminaire is an efficient luminaire, dimming is often necessary and the dimming feature is useful. A professional LED dealer can also offer you solutions for wired and wireless dimming of your luminaires. So as a buyer of LEDs, you should also require the salesperson to have knowledge of dimmers for the lamps you are buying.
3. Colour of light emitted by the lamp, kelvin
The mood and cosiness created by lighting, or the energising effect it has on the room, is partly influenced by the kind of light it provides. In many cases, LEDEs offer a choice of 3 000 kelvin warm tones of light perceived as cosy and 4 000 kelvin neutral white light perceived as brighter/bluer. In addition, LED luminaires are available that emulate bright daylight of around 5 500 kelvin. If many colours of light are on at the same time in the same room, the difference is noticeable to the eye and the lighting may appear unbalanced. If you want to know what kind of light you are buying, pay attention to the colour temperature, or kelvin, indicated on the bulb.
4. Amount of light indicated, lumens (lm)
The wattage of an LED lamp does not indicate the amount of light the LED produces. In the case of incandescent and halogen lamps, we used to talk about bulbs of a certain wattage (W), so the amount of luminous flux (lumens) was not specifically used to define the “luminous intensity” of the light. With LED technology, the same amount of light is produced with a lower wattage, so the term lumen is the correct one to use when comparing the amount of light. For example, a 7W E27 bulb produces the same amount of light as a 60W incandescent bulb, i.e. just over 700 lumens.
5. Metal frame material
Although LED lamps do not heat up nearly as much as incandescent or halogen lamps, proper cooling will prolong their life. So it’s a good idea to have enough metal in the body of an LED downlight or spotlight, such as aluminium, which has excellent thermal conductivity. An excessively rigid body, which does not conduct the heat generated by the lamp away from the LED circuit, will shorten the life of the LED. A properly cooled, flush-mounted LED downlight and panel will burn at around 30 degrees Celsius. It is also important to mount the LED strip in an aluminium profile, or other metal, to achieve the desired lifetime and therefore ecological performance. The LED strip does not contain any heat-conducting materials, which means that the LED strip will not cool easily if it is installed in a heat-conducting material such as wood. Although there is no fire risk, our experience is that without conducting heat away from the LED, the surface of the LED will heat up to over 60 degrees depending on the power of the LED strip, which will shorten its lifetime considerably.
6. Will a power supply be included, is there an additional cost?
LED downlights, ceiling and wall lights, and LED strip and continuous row luminaires are usually recessed luminaires, i.e. they cannot be plugged directly into a socket. The power supply of a luminaire affects its dimming and installation. The power supply is not always included in the stated price of the luminaire. A good quality power supply or transformer is as important as the luminaire itself and will be an additional cost if not included in the luminaire. On the other hand, the overall price can be influenced by choosing the power and characteristics of the transformer according to the application. Especially in LED strip installations, where the total length of the strip always affects the size of the transformer to be selected, it is important to choose the right transformer.
7. How to install
Especially when installing LED spotlights, it is important whether the luminaires are chainable. Chainable luminaires with their own power supply are ideal, as they save considerable time and therefore money during installation. The advantage of chaining over star connection is a more straightforward installation, and considerably less electrical wiring and connections. LEDs usually do not have a replaceable luminaire module, so when an LED fails or reaches the end of its life, the entire luminaire must be replaced. Fortunately, there are also LED luminaires with replaceable modules.
8. Does the seller give a fair guarantee for the products?
How can you tell the quality of a product? Product importers and sellers are responsible for their products and their quality. In case of errors, a responsible seller will act without hesitation and in the best interest of the customer. The fact that products come with a long warranty is a sign of the quality of the products sold.
9. Does the trader have a place of business where you can go to check that the products are what they say they are?
Selling lighting on the internet is challenging because of the nature of light. Light is a sensory thing, and a successful luminaire may not look very different from its competitors. It is good if the light produced by the products can be experienced in the shop or showroom, especially if it is a large purchase. It is also good if the salesperson can be contacted for detailed design questions through various channels.
10. Does the seller use real photos?
When selling lighting products, it is important to show the customer not only pictures of the products but also pictures of the illuminated spaces and objects. In addition to pictures of real objects lit by the products of the seller, so-called illustrations can be used to create an impression of the final lighting results and the applications of the types of luminaires. In our view, it is good commercial practice that these illustrations/photos should be distinguishable to the customer from the “real” pictures, where the products sold by the company are actually used as lamps in the picture. When buying LEDs, a good result is achieved when you get genuine reference photos from the seller.
Read more about the topic in the following blog articles:
We have written about colour rendering: what is the difference between CRI and Ra values in the colour rendering of LEDs. Read our article on wireless dimming: VaLO – wireless control of lighting Read more about wireless dimming: ABB and Schneider wireless dimmers for LedStore luminaires Read more about colour temperature selection: light colour temperature and its selection in LED lighting. Read about the factors that affect the price of an LED luminaire: the price of LED luminaires – what does an LED luminaire cost?
