You can have glass with or without a low e coating.
Double pane low e windows.
In other words this sheet can effectively turn a double pane into a triple pane and this insulation can be further supplemented with the addition of inert argon gas for even more r value.
As with moderate solar gain low e glass these windows are often referred to as spectrally selective low e glass due to their ability to reduce solar heat gain while retaining high visible transmittance.
The biggest drawback of low e windows is primarily cosmetic.
Triple pane windows cost approximately a third more than a double pane window.
The bigger windows solution can then create additional heat loss issues leading to a downward spiral in performance coupled with an increase in costs.
To keep in the infrared light.
Soft coat windows have much better u value than hard coat surfaces and allow less uv transmittance by almost 75 over clear glass.
However low e coating is not a standalone material.
The term double pane refers to a window that has two pieces of glass while low e is a coating technique.
How does it heat the home.
When first invented in the 80s low e windows only came in one variety for one purpose.
Low e windows are covered in a film like coating that traps warmth prevents drafts and reflects sunlight in the summer to aid in cooling the home.
It requires a sheet of glass as a base material for its application.
Double glazed low solar gain low e glass.
The energy saving cost is minimal over that of a double pane window with low e coating.
While low e glass is generally cheaper than double glazing it will also reduce you winter heat gain leading to a need for either a bigger windows b more mechanical heating.
This figure illustrates the characteristics of a typical double glazed window with a low solar gain low e glass with argon gas fill.
On the other hand soft coat low e windows must be in a double pane unit and are nearly invisible coatings which provide more visible light.