Yes, CFL and LED bulbs can be used in Line Voltage Housings and Trims. These types of bulbs are readily available in Par, R, and A-shaped bulbs. It's important to note, that the shape of the bulb should be as close to the bulb specified by the manufacturer as possible. For example, if the housing and trim are recommending a Par/R-shaped bulb, the CFL or LED bulb should be in a Par/R shape. Spiral CFL bulbs can be used as they have the same socket base as a Par/R bulb, however, due to the length and width of some bulbs, the light pattern given off by the bulb and the overall look, may not be what was originally intended.