Glass used in most double glazed units is easily scratched and it is recommended that hand jewellery is removed prior to cleaning.
Glass areas should be cleaned on a monthly basis using either a proprietary glass cleaner or clean water, a dash of vinegar and a soft cloth. For extra shine, buff the glass with newspaper.
Low emissivity glass is an essential component of energy efficient windows and doors and is used to significantly increase the insulation properties of your windows. It uses a metallic surface coating which under some light conditions can create a hazing, or light tint effect.
This has no detrimental effect to the function of the window and is not deemed to be a defect.
The visual quality of a double glazed unit is assessed by looking through it from the room side, at right angles to the glass and standing at a distance of no less than two metres for a float glass unit and three metres for a toughened or laminated glass unit. It should only be viewed in natural daylight and not direct sunlight, with no visible moisture on the surface of the glass. Provided that your vision is not disturbed under these conditions, for example by bubbles or scratches, then the glass is deemed to be of good visual quality.
Lead work detail on double glazed units is typically bonded to the surface and care should be taken as excessive pressure may dislodge the lead from the glass. The use of warm soapy water and a soft cloth moderately applied will prove an adequate cleaning method.