Energy efficiency for windows and doors
Whether you're renovating or building a new house, it is important to consider the energy efficiency of your future windows and doors. Depending on your location and country, regulations can be an issue. Not only will we provide your home with quality energy-efficient products, Lepage will answer any questions you might have to ensure you choose the right product for your project.
Values you should look for
U Factor: Represents the rate at which a window or a door conducts non-solar heat flow. In other words, this factor measures how well the products keep the heat inside your home. The lower the number, the better the performance.
Solar heat gain coefficient: Represents the fraction of solar radiation entering through a window or a door. Simply put, this coefficient measures how much heat is transmitted through your windows and doors into your home. A lower SHGC means a lower heat transmittance and a greater shading ability. On the other hand, a greater SHGC means that more solar heat is kept inside during winter.
Visible transmittance (VT): Represents the amount of daylight a window or a door will let through. The higher the value of VT, the greater the amount of daylight will enter into your home. Low-E coatings can bring variations to your product’s visible transmittance.
Glass and glazing
Low-E Coatings and Insulated Glass VS Single Clear Glass
Energy efficiency has a lot to do with glass and glazing. In fact, over 80% of energy transmittance through windows and doors is related to the quality of glass you have.
The first way to maximize energy performance is to lower heat transmittance. Insulated glass consists of two or more glass sheets separated by air or harmless gas to minimize thermal transmittance. Argon gas, for example, is used in Lepage’s insulated glass for its thermal properties.
Low-E stands for low emissivity. For windows and doors, glass emissivity represents the level of heat radiation that is transmitted through the glass.
A Low-E coating increases the energy performance of a window or door by reflecting or letting through light and heat. This technology is sprayed on or applied as a metallic film on one surface of the glass. Depending on your region, the Low-E options can vary according to your location’s weather. Lepage offers a variety of the latest Low-E coatings to address your home's unique requirements.
Double Glaze Unit
Double glazing consists of two glass sheets separated by air or argon gas and a spacer bar to seal the unit. More surfaces are thus available to apply the Low-E coatings.
Triple Glaze Unit
Triple glaze units have three glass sheets, each separated by air or argon gas. With an extra sheet of glass, there are more surface options to apply the Low-E coatings and then reach different energy standards. Sound transmittance is also greatly reduced by using a triple glaze.


Energy Star
Energy Star is an internationally recognized brand and a trusted symbol for identifying energy-efficient products. In terms of windows and doors, Energy Star requirements are represented by the U factor and the solar heat coefficient, depending on where your home is located. Each region, considering average weather and heat exposure, will need to meet different requirements to comply with the Energy Star standard and obtain this certification.