Heat travels in three modes, and vacuum effectively eliminates two of them: conduction and convection. Researchers at Guardian Industries have recently unveiled a new breed of vacuum-glazed super glass with an incredible RI 2-RI 3 insulation rating. That means this new vacuum glass is as isolative as a thick insulated wall. Guardian Industries has under development a revolutionary vacuum-glazing panel that provides a center-of-glass insulating value of R-12 to R-13. The glass has a very thin (250-micron or 0.25-mm) vacuum space. Using the same principle as a vacuum thermos bottle, these glass panels essentially negate two principal modes of heat transfer, paving the way towards windows that actually supply thermal energy instead of leaking it.