In window insulation, krypton is useful as it has a low thermal conductivity and is a relatively dense gas. When used as a filler gas between two or three-ply window planes, it increases heat insulation and creates an energy-saving window by reducing solar radiation. Air Products produces krypton, xenon and rare gas mixtures to increase R-value and reduce U-factors for windows and doors to your requirements.
As a lighting gas, krypton has a blue-green light, and is traditionally used in halogen bulbs, energy saving bulbs and even neon-signs gas discharge tubes. Using krypton instead of nitrogen or argon increases the lifespan of the light bulbs greatly as krypton is highly stable and unreactive.