Cracking the Mystery: What Makes the Best Energy Efficient Windows Work?

Cracking the Mystery: What Makes the Best Energy Efficient Windows Work?

December 5, 2018
Martin Whitmore, President of US Window & Door
Best Energy Efficient Windows

Did you know that homeowners can save $126 to $465 a year when they upgrade their single-pane windows?

Energy efficient windows are an important addition to your home. They can help you save on your energy bills while keeping your home insulated.

Keep reading to learn what makes the best energy efficient windows.

Window Technology

Let’s face it, if you don’t have energy efficient windows, you could be losing a lot of money in AC and heating costs.

The way smart windows work is by using the latest technology to ensure they are as energy efficient as possible. Energy efficient windows have key components such as glass, spacers, and coating to insulate the windows.

When homeowners invest in energy efficient windows, they receive cutting-edge technology that will help them cut down on electricity bills and keep their houses warm or cool.

Energy efficient window technology uses different techniques such as using multiple panes of glass, gas, and glass that block UV rays.

Spacer System

As we briefly mentioned before, a great smart window needs a spacer. The spacers act like sealers between the glass panes and the window. These are small brackets that go on each side of the glass panels and hold them still against the sash and frame.

Spacers are extremely important for energy efficient windows. On the outside, windows are exposed to UV rays and extreme weather conditions. If the windows don’t have the proper spacer, they can let some of the cold or hot air through.

The outside of the window is not the only side that faces changes in temperature. For example, there are temperature changes on the inside of the windows too.

With both changes in temperature, the edges of where the glass and the frame meets can be subjected to a lot of condensation. The condensation will damage the frame and lose any kind of insulated coating.

Energy efficient windows use a spacer to do the following:

  • Block water, vapor, and moisture
  • Prevent damage caused by expansion and thermal contraction
  • Creates a tight seal
  • Increases the temperature on the edges of the window to stop condensation

The spacer is an essential component of energy efficient windows.

Glass Coating

Not all energy efficient windows are created equal. Some energy efficient windows have different types of glass panes or combined the panes to create a better window.

Low-E Glass

Low-emissivity or Low-E glass is a type of glass created to stop the ultraviolet and infrared light that comes through your window. Low-E windows stop the UV rays without impacting the light that comes through.

Low-E glass has a thin coat, thinner than a hair, that traps the rays that affect the temperature inside your home.

Low-E glass also comes in two types of coatings passive (hard-coat) and solar control (soft-coat).

Passive coats have a pyrolytic coating. The glass ribbon and the pyrolytic coat then fuse to create a strong bond.

Solar control Low-E coating, on the other hand, are created using a different method. This coat is applied to the pre-cut glass using a vacuum method at room temperature.

Sof-coats are the highest performing windows since they use lower emissivity.

The Low-E coatings have to have the following factors to measure their effectiveness:

Solar Heat Gain Coefficient (SHGC): This is the solar radiation that comes through the window. The radiation can come through directly or absorbed by the window.

Light to Solar Gain: Light to solar gain measures the ratio of visible light transmitted and the solar coefficient rating.

U-Value: It rates the window based on the heat loss.

Visible Light Transmittance (VLT): VLT will measure how much light passes through.

Double and Triple Pane Glass

If you purchased an older home or rented from an outdated building, then you might have noticed the windows only have one pane of glass. Having a single pane doesn’t offer a barrier to prevent energy loss.

Single glass panes also let the cold weather in the winter and cause condensation and let in the humidity.

Energy efficient windows, on the other hand, have either two or three panes of glass. The multi-layer panes prevent the harsh weather conditions to come through the windows.

Gas Filled

Some energy efficient windows use non-toxic gasses in between the glass panes. The gas serves as an extra insulator and increases energy efficiency.

The type of gas they use depends on the glass pane and installation but some people use Krypton and Argon as a filler.

Types of Frames

When it comes to energy efficient windows, the frame is also important. There are different types of frames to choose from depending on the budget.


Vinyl window frames are a budget-friendly option. Vinyl has a reputation for being cheap, but that doesn’t mean it’s not a quality material.

This material, when properly installed, can prevent air from leaking in.

However, vinyl doesn’t offer many choices as far as color and variety.


Aluminum is best suited for climates that are humid and rainy. You will see more aluminum frames in places that are near the coast or prone to tropical storms and hurricanes.

What Makes the Best Energy Efficient Windows: The Bottom Line

The best energy efficient windows have a few components such as multiple glass panes, spacer, and an insulated coating.

Having the right energy efficient windows can help you save money on your energy bills and keep home heated or cool.

Are you ready for energy efficient windows? Contact us at US Window & Door for a free estimate and save on your energy bills.