In our last installment we looked at a lot of different topics. We recapped our look at electrochromics (windows or glass doors that change in appearance when a measured electrical signal is passed through them), we discussed the electromagnetic spectrum, and we touched on the ever-important emergency exit window. This week we are going to kick it up a notch in our exploration of the wide world of aluminum windows, vinyl windows, patio doors, storm doors, replacement doors, and window manufacturing with the glossary term evacuated glazing.  Evacuated glazing is basically an insulating glazing made up of two layers of glass, which are sealed at the edges, and have a vacuum between the two panes to help eliminate convection as well as conduction. If you were here for last week’s discussion, don’t be confused, we have moved on past looking at emergency exit windows, so when we talk about evacuation, we aren’t talking about leaving a building through a fire escape. Also, we should make it clear that when we refer to a vacuum, we aren’t talking about some vacuum cleaner stuck between two panes of glass. In this instance, when we refer to vacuum, we’re referring to a cavity from which all the air has been removed. This practice is common for insulating purposes, as the medium of conduction and convection (the air molecules within the cavity) have been removed. If you have been reading along all these years, then you probably know what is coming. We have hair trigger sensitivity to talking about energy efficiency. The slightest mention can trigger a dissertation on the importance of energy efficiency, and today is no different. Evacuated glazing is one weapon in an arsenal of tools that can help reduce the impact of heating and cooling costs by reducing the need.