Researchers with a selection of energy-efficient light bulbs. The increase in efficiency of lighting is one of the major areas of domestic energy conservation. Most of the bulbs seen here are modified fluorescent lamps. These have a high efficiency compared to normal filament bulbs. The two spherical bulbs are coated with an infra-red reflecting layer. This allows visible light to pass through, but reflects heat back toward the filament. This means that less energy is used to heat the filament to produce a given light output. Although not as efficient as fluorescent lamps, this bulb shows an energy saving of around 50%.