Argon-injected insulated glazing shows a sign to see the light. In May of last year, the Agency for Natural Resources and Energy added the word “Window” to the applicable items for the Top Runner System aiming to attain a higher level within a period of 3 to 10 years based on the existing most excellent energy-saving efficiency of each product.

A total of 28 machines and equipment including air-conditioners and refrigerators have already been nominated as applicable to this system, and it is mandatory for the manufacturers and sellers of these products to indicate their energy-saving efficiency. In October of the same year, a standard was provided to evaluate by energy consumption the energy-saving effect of a whole house including window glass, and it was enacted to be mandatory for a large-scale building to comply with the standard by 2016, a medium-sized building by 2018 and a small-sized structure by 2020. In line with the movement it is an insulated-glazing glass that is expected to be a powerful card of the energy-saving enhancement of window glass.

The insulated-glazing glass which already accounts for 94.2% (2012) as window panes for new free-standing houses has a structure with dry air or argon into between double window panes. The argon-insulated products delivered account for only several percent of the whole insulated-glazing glass. Predominating now is Low-E Glass coated with the metal film (Low-E film) which controls conductivity inside the glass as a method to enhance heat insulation effect. According to the statistics of Flat Glass Manufacturers Association of Japan, the penetration rate of Low-E Glass to new free-standing houses rapidly rose from 19.1% to 54.5% during the period of 2006-2012. One of the Low-E lineups is argon insulated-glazing. In case that the ordinary insulated glass is replaced with Low-E, an insulation effect increases by 30% or 40%. Furthermore, in case that the air space is replaced with an argon layer, the insulation effect additionally increases by 20%. However, as some users regard Low-E only can do well enough, the argon glazing stays as one of the options to be taken in case a Low-E user seeks a higher insulation efficiency.

There are two methods to manufacture a gas-injected insulated glazing glass. One is tight sealing in between two sheets of glass by compressor in the manufacturing process of insulated glazing glass, which is suitable for a mass production line like an automobile assembling process. The other method is to make a hole in the spacer part of the once assembled insulated-glazing glass, from which gas is injected for replacement with air. It is utilized in case of a small portion of gas-insulated product for the whole production. The former method costs higher than the latter, but is superior in productivity. All of the manufacturers regard the former will be the main player as more demand is expected for gas-injected products following the scheduled revision of law.

For reference, the area of window pane in each free-standing house is 20 square meter on the average. In Japan about 400 thousand new free-standing houses are built annually. On the assumption that their insulated glazing is 12mm thick and all the window panes are argon injected, there could be a newly created demand of argon totaling 96 thousand cubic meter annually.