Assume that I’m someone who is already enlightened about the benefits of LED (Light Emitting Diode) lighting. Very interested, I have made up my mind to upgrade my home lighting to LED soon. I’m prepared to pay for the higher initial costs of LED lighting products LED Display
But before I buy, the first question that comes to mind is what power of lighting to choose for the same brightness I have/use now. Then, I begin to wonder whether I can easily retrofit my new LED lights into the existing electrical fixtures in my house. As I’m not sure, I try to find out from the Internet by searching for (maybe) ‘how to migrate to LED lighting’. While I get some useful answers, I also run into a whole lot of new terms that I know little about like ‘diode’, ‘semiconductor’, ‘photon’, ‘lumen’, ‘CRI’, ‘CCT’ and so on. My lack of knowledge makes me unsure of myself, so I begin to wonder, ‘Can I ignore the new terms and proceed safely?’. ‘If I do, will my LED project be successful?’.
Not to worry – these are typical roadblocks we all run into. But before you decide to hire a consultant, read the solutions presented in this article. For all you know, after reading through, you may find that you don’t really have to!
Problem 1 – DETERMINING EQUIVALENT LED LUMINOSITY BY POWER IN WATTS:
Manufacturers are increasingly providing this info on the cartons of LED bulbs and tubes by phrases such as ’40 Watt equal’, ’60 Watt Replacement’ etc. so this problem could be treated as ‘already solved’, in many instances. If not, to decide on the power rating of the LED light to buy that’s equivalent to any of your present non-LED lights, use one of these methods:
(A) Rule-of-thumb: Calculate proportionately, using 70W incandescent=50W Halogen=18W CFL=15W LED.
CAUTION: This method does not produce accurate enough results to enable you to safely buy/install LED products. It only gives you a fairly correct value; one that should be used in an emergency. It may also help you make an accurate guess, once you get used to it. Here’s an example: You need to replace a 100W incandescent bulb with LED. This rule-of-thumb will point you to a 22W LED bulb (i.e. by the calculation,100/70 * 15, decimals being rounded-up to the next higher whole number). The exact LED power required is 27 W, so that the result is lower by 5W (about -19%). But you can make a good guess at this point because LED power ratings can take only certain standard values like 7W,11W,14W&27W. Since you need to make a guess starting with an approximate value of 22W, its very likely that you will choose 27W rather than 14W, since 22 is closer to 27 than to 14.
(B) Switch to thinking in terms of Lumens(lm): This method is easier and highly recommended. However, you might need to change your way of thinking a bit – think in ‘lumens’ (or brightness) instead of ‘watts’
When we say ‘an equivalent light source’ we mean a source that produces the same amount of brightness (or luminosity) as the one to be replaced. The unit of measure for brightness of light is the ‘Lumen’ (lm) (Note: To get an idea of Lumen power, remember that a single, burning wax candle produces around 13 lm of light). Quantifying brightness in terms of lm is the straight-forward way to do it, while watts is round-about, from the viewpoint of a light designer. Apart from being indirect, wattage is not a standard measure across different light types since the lm produced by each, for the same no. of watts, is not the same. Hence, the strong recommendation for adopting the practice of thinking in terms of lumens instead of watts for lighting applications in future.