You are correct, LEDs are not yet there in terms of both color temperature and in color rendering index (CRI). Also, there has been insufficient research on their UV component. I would imagine that mass production of LEDs for museum use (color temperatures of daylight and CRIs of 92+) are probably 10 years into the future, but who knows.

Fluorescent fixtures tend to be undirected light. That means that the light goes in all directions. T-8 fixtures tend to generally deflect light in the intended direction, but usually this reduces light from 360 degrees to 180 degrees. They are fine for general area lighting, but rather poor for object lighting. Many types of halogen bulbs exist, but all are incandescent. This means that energy consumption for the same type of light dispersion and intensity as fluorescents is 2-4 times greater. However, halogen bulbs can be directed. If this light is focused on objects, rather than general lighting, energy savings can actually be realized over T-8 bulbs. But, this requires a carefully designed lighting plan. Perhaps the most applicable bulb type for museums is the MR-16 bulb. These bulbs will have higher wattages (more energy required) than the T-8 bulbs for the same light output, but if the light is focused through different beam spreads accomplished through reflectors built into the bulbs, the overall wattages can be reduced, often to below T-8 levels, with ensuing energy savings. MR-16 bulbs also can have filters added to spread the light more fully, to filter UV or for other applications. It would seem logical that quality MR-16 LEDs would eventually be available. But not yet.

What type of halogen fixtures/bulbs did you install? Have you measured the actual light levels falling on objects before and after the transition? It is possible that your light levels on objects are much higher and can be reduced either by rheostats or lower wattage bulbs to be equal or even be lower than previous power consumption levels.

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