A CALiPER Application Summary report shows how far LEDs in MR16 format have come -- and how far they have yet to go.
Here is the CALiPER report's capsule description of the state of LED-based MR16 lamps in the spring of 2014:
Market-available products still do not produce the lumen output and center beam intensity of typical 50W halogen MR16 lamps. In fact, most of the 18 lamps in this category had lower lumen output and center beam intensity than a typical 35W halogen MR16 lamp.
For this report, Pacific Northwest National Laboratory selected and purchased (on the open market) LED-based MR16 luminaires that met one or more of four criteria: output above 500 lm, beam angle at or below 15°, CRI above 90, and efficacy greater than 60 lm/W. Twenty-seven lamps were purchased and bench tested. Significantly, the report notes that none met all four of the selection criteria.
When the market develops to the point at which an LED MR16 does meet all four, "this would be an important achievement for LED MR16s -- especially if output could reach approximately 700–800 lm, approximately equivalent to that of a 50 W halogen MR16 lamp."
The illustration shows the lumen outputs and efficacies of the tested lamps against the background of the products in the Energy Star and Lighting Facts databases. Halogen MR16s are also plotted (bottom right). Few of the tested lamps produced output even in the range of the 35W halogen reference lamps, though many of the LEDs claimed to be replacements for 50W halogens, and a few even claimed to replace 65W and 75W halogens.
Only a few of the tested lamps exhibited a center beam intensity comparable to the reference 35W halogen MR16s. None came near the 50W halogens.
In earlier CALiPER testing of MR16 lamps (in 2012 and before), the maximum output of any lamp examined was 327 lm. All but five of the lamps tested in this round exceeded that mark, and their output ranged up to 585 lm. Clearly LED are managing to pack more punch in the demanding MR16 form factor -- two inches (5 cm) across and about the same in depth. However, they are doing it at increasing levels of input power, and the report notes that luminous efficacies have not risen much in this product class in the last few years.
Given how far current products are from L Prize level in the far less demanding PAR38 form factor, how long do you think it will be until LEDs provide real competition to halogen MR16s?
— Keith Dawson , Editor-in-Chief, All LED Lighting