| Downlighting Quality
The table below compares three fixtures/lamping options in terms of color quality measures, luminous intensity, beam angle, and average luminance. (See Table 1 for more performance information on these and other recessed downlight sources.)
Table 2: Comparison of Recessed Downlight Lamping Options |
| |
65W BR-30
Flood |
13W 4-pin
Spiral CFL |
LED 2 |
| Luminaire light output, initial (lumens) |
570 |
514 |
730 |
| Luminaire wattage (W) |
65 |
12 |
12 |
| Luminaire efficacy (lm/W) |
9 |
42 |
60 |
| CCT (Kelvin) |
2700 K |
2700 K |
2700 K |
| CRI |
100 |
82 |
95 |
| Center beam candlepower (candela) |
510 cd |
154 cd |
280 cd |
| Beam angle (degrees) |
55° |
120° |
105° |
| Average luminance at 45° (cd/sq meter) |
27267 |
13479 |
16439 |
| Dimmable |
Y |
N |
Y |
Based on photometric reports for three products.
The downlight using an incandescent reflector flood lamp provides more light in the center of the beam (center beam candlepower) and a narrower beam than either the CFL or LED downlights. Depending on the application this may be an important consideration. But on total luminous flux, color temperature, and color rendering, both the CFL and LED products are good options.
Residential downlights are often a glare problem, as indicated by the high average luminance figures for all three of these products. For the products listed above, both the CFL and LED alternatives would be an improvement over the most common lamp type used in residential downlights, the 65-watt reflector flood, but particularly in lower ceilings, glare may be an issue. Using louvers, shielding trim, or deeper recessing of the light source alleviates glare, as does dimming. Alternatively, wall sconces, cove lights, wall washers, or torchieres may be better options for lighting the room because they diffuse light over a large surface (the wall or ceiling), while completely hiding the light source. |
