save energy with solar window film

How does Window Film lower my heating bills?

Not only can the solar window film I installed myself help block the sun's heat during the summer and lower my cooling bills, but it can also help lower my heating bills in the winter! All of this while blocking 99% of UV rays…and I did it myself…in a few minutes on a Saturday? You may be thinking this sounds too good to be true, but here's how window film works to save you money on utility bills.

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First let's talk science!

There are three forms of heat transfer: radiation, conduction, and convection. Heat transfer through Radiation comes from a source such as the sun through waves. Glass will absorb some amounts of heat through conduction and will transfer some of that heat directly to the air in contact with the glass, but more importantly through the framing system in contact with the glass. Window Film acts in a similar fashion, and since it is in contact with the glass, is part of the conduction process absorbing heat.

Convection is heat transfer between a solid and a gas (i.e. the air) and plays a big part in why double paned windows are better than single paned windows. As wind blows (convection) the outside of your window is replaced with colder air, and the warmer air inside your house is pulled through the glass (conduction) and there is significant heat loss – AKA: your money being sucked out through your windows.

How window film lowers your winter heating bills

Lowering Heat Loss with Window Film

Great! Now how do we fix this? U-Value, sometimes called U-Factor. If you lower your U-Value, you will increase your R-Value: your insulation rating. R-Value= 1/(U-Value)

Installing window film to your existing glass unit will actually lower the U-Value of your window unit. It adds an added layer to your glass lowering the rate of convection (heat loss)!

R-Value is used to measure insulating ratings. When you want to add insulation to your attic you typically will purchase some R-13 fiberglass insulation from Lowe's or Home Depot. A typical window film has an R value around "R-1" so it's like adding R-1 insulation to your windows! You lower convection (heat loss) and therefore save on heating bills – all with window film you installed yourself in one Saturday.