A new kind of glass could make houses happier and healthier, German scientists have claimed.

Normal glass blocks some light including blue light.  However, blue light governs people's 'biological clocks', which tell us when to sleep and wake up.  So missing out on blue light can have important knock-on effects on mood and health.

Modern heat-insulating, sun-protection glazing for offices and housing isn't optimized to allow the light that governs our hormonal balance to pass through. 

A new glass, called Uniglas Vital has been designed to let blue light pass through.  The effect is like leaving a window open.  The secret is a special, long-lasting and barely perceptible inorganic coating that is only 0.1 micrometers thick.  The glass transmits light most at wavelengths between 450 and 500 nanometers which is exactly where the effects of blue light are at their strongest.

The new glass was announced by Fraunhofer recently although as yet there is no price or release date.