Window World’s new replacement windows provide substantial energy efficiency and savings for your home. We have saved money and energy for homeowners throughout the nation.

Help Save Energy and the Environment

Energy Efficient Windows
In most instances your windows come standard with the ENERGYSTAR® Qualified SolarZone™ Insulated Glass Package.

Window World of Connecticut’s Windows are already designed for superior thermal performance. By choosing our SolarZone™ Insulated Glass Package, featuring the Intercept™ Warm Edge Spacer System, you can help reduce your energy costs even more, while helping cut consumption of the fossil fuels that pollute our environment.


What Makes the SolarZone™ Insulated Glass Package So Effective?

Since over 80% of a window is glass, substantial heating and cooling savings come from improved glass performance.

  • Our Intercept™ Warm Edge Spacer System, creates significant energy efficiency. It can cut the damaging effects of the sun, which can lead to the fading of carpets, curtains and furniture by an additional 72% over clear insulated glass units.
  • In winter, a warmer glass temperature is maintained, increasing the R-value by an additional 104%.
  • In summer, a 49% reduction in solar heat gain helps cut air conditioning costs.

The result: your monthly utility bills will reflect savings year round and that should help make you even more comfortable.


Spacer SystemThe Benefits of the Intercept™ Warm-Edge Spacer System

The Intercept spacer system features a unique, one-piece metal alloy, U-channel design that creates an effective thermal barrier to help reduce conducted heat loss through the window. Its sealed, one piece design makes Intercept spacers stronger and better at retaining insulating gas than many conventional designs.


Energy Efficiency, It All Adds Up

Energy Efficient Windows

There are many options available for improving the performance of a window. By adding Low-E glass to a standard insulating glass unit, you can improve the energy performance of your window year round by 24%. Additionally, by adding argon gas filling to the window, you can increase the efficiency by another 6%. And finally, by adding the Intercept™ Warm Edge Spacer System, you can add yet another 5% to the overall efficiency of your window. So, wouldn’t you agree that when you add all of these together, by choosing Window World Windows with the SolarZone™ Insulated Glass Package, you have chosen the most energy efficient window product on the market today?


Comfortable Rooms Start With the Intercept™ Spacers

Intercept spacers are so energy efficient that they keep the edges of the window glass warmer, so your home feels more comfortable in the winter. As you can see below, the temperature difference between the edge of an insulating glass unit with an ordinary spacer, and one with an Intercept spacer system can be dramatic.

Intercept Spacers

Intercept I.G. units feature Warm-Edge technology that reduces condensation problems around the window perimeter. Compare the Intercept insulating glass window above left with a conventional insulating glass window above right. The difference is the Intercept Warm-Edge Spacer.

Energy Saving Performance

This thermograph or heat picture compares room side glass temperature for an Intercept I.G. unit (left, yellow is warmer, blue is cooler), and a conventional I.G. unit (right). Since the Intercept I.G. allows for significantly warmer glass temperature, especially at the edges, your home will feel more comfortable.


  • Cold side temperature = 0 F.
  • Room side temperature = 72 F.
  • Room side relative humidity = 25%


The Intercept™ Spacer Helps Your Windows Last Longer

Under normal weather conditions, I.G. units expand and contract with temperature changes. In conventional insulating glass units, the sealant (the material that holds the unit together) takes the stress of the flexing. This can cause seal failure and insulating gas loss. In an Intercept I.G. unit, the spacer flexes instead of the sealant, so it resists spacer movement and premature sealant failure.

Window Temperatures


Measuring Heat Loss Through U-Values

For all window products, the National Fenestration Rating Council (NFRC) has created the NFRC-100, which is the standard test for heat loss through a fenestration, or window product. Once the testing procedure is completed, a U-Value rating is applied to the window product. The lower the U-Value, the better the product is at resisting heat loss.

Window Glass Options