Energy Efficient Windows

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1.  Independent studies conclude that using low-e glass and using a low conductance gas such as argon may improve the energy efficiency of a window 100% over clear glass.
2.  Homes may lose up to 30% of heat or air conditioing through its windows.
3. According to PSE&G, for every 1° F increase on the thermostat, energy use increases 2%.
4.  The ROI on upgrading to Energy Star® rated windows can be as soon as 2 years and at most 10 years, while the expected life span of the window is a minimum of 25 years. As soon as 2 years, these 
      windows can actually make you money!
1.   Conduction: The transfer of heat through a solid material.
       A.  The less conductive a material is, the less heator cold will transfer through.
2.  Convection: Movement of heat from a hot to cold region
       A.  The cold outside pane of glass meets a warmer surface on the heated inside pane.  When this happens,the air against the inside pane of glass cools, becomes dense and drops to the floor.  Often, this is felt as a draft when in fact, it is the interior house air currents rotating. Warm air rises, cool air drops.  The circular movement can be felt as a draft.
 3.  Radiation (Radiant Heat): Movement of long eavelength heat energy from a warmer body to a cooler body.
       A.  In the winter, glass absorbs head and radiates it outdoors.
       B.  Inthe summer,the suns rays (UV and IR)heat your house from the outside. This is called solar Heat Gain or SHGC (solar heat gain co-efficient).
4.  Air leakage: Leakage of air through winows via surface intefaces of the window
       A. Glass to sash 
       B.  Sash to frame
       C. Frame to frame.
1. Upgrade from clear single or insulated glass to a Certified  Energy Star® rated Warm Edge glass package which should contain:
       A.  Low-E Glass
              1..  A slightly tinted transparent metallic oxide coating is applied to the glass.  In the cooling season when the sun is high in the sky with
a high angle of incidence, this coating results in a reflection up to 90% of the sun's long wave heat energy (UV) back outside the house. 
              2.  In the heating season when the sun is lower in the sky with a lower angle of incidence, it reflects long wave radient heat back into
the house where the energy is absorbed by the walls, floors,  furniture,etc.
              3.  Allows visible light to pass through
              4.  Improves insulating value as much as adding another pane of glass (storm window)
      B.  Low Conductive Gas (Argon)
               5.  Pumped under pressure between two or three panes of glass. this gas forms a barrier preventing the conduction of heat or cold through the glass.
               6.  Safe, inert, non-toxic. It's in the air we breathe.
      C.  Use of non-metallic (aluminum or steel) spacers such as Super Spacer® that separate the glass panes from each other prevent conduction through the edges of the glass panes.