Qualm entered English in the 16th century, with meanings like doubt and uneasiness.. Usually a qualm comes from doubt about an action and a feeling that you are doing, or are about to do, something wrong. It isnt a bad feeling about another person's behavior but about your own.
The newest type of grow lights use LED technology. One major advantage to the LED lights is the small size. LED lights are only a few inches in diameter and are easy to mount. In some greenhouses, LED lights may be the only practical light option.
There is some confusion about this because compact fluorescent light bulbs (or CFLs) have typically been referred to as 'low energy light bulbs' by retailers. However, the reality is that there are a number of different kinds of low energy light bulbs available, including CFL and LED light bulbs. Just to make things more confusing, some rather inefficient lighting products, such as traditional incandescent and halogen bulbs, come in 'low energy' versions.