Beyond just their aesthetic impact, windows significantly influence both the indoor and outdoor atmosphere of homes and commercial buildings. Windows are not only integral to the overall appearance of a property’s interior and exterior, but they also play a key role in the living environment within. For decades the central role of windows in any building was letting light in. Unfortunately, all too often, they did a good job of letting the cold in during the winter and out in summer too. 

As homeowners, property owners, and developers have become more concerned with the environment and comfort, the benefits of energy-efficient windows have become more apparent. Today, many homes and buildings are being outfitted with energy-efficient, thermally broken steel windows. Steel, in particular, is extremely durable, long-lasting, provides unmatched security, and is customizable to fit the style of space seamlessly. One of the most important advantages of French Steel™ windows is that thorough insulation of the frame and double-paned glass offers excellent energy efficiency in a handsome package that looks sharp on any property.

What Is Energy Efficiency?

In today’s environmentally-focused world, “energy efficiency” is a common term used in a variety of settings. Using high-quality materials to insulate a building to lower the amount of energy needed to heat or cool it is probably a familiar idea. It should come as no surprise that windows play a major role in how energy efficient a home or commercial building is. Windows are the dividing line between interior and outdoor spaces, and 25-30% of the energy used for heating and cooling is from heat gain or loss through a structure’s windows. The benefits of energy-efficient windows come from reducing this heat gain and loss, resulting in savings on the energy spent to create a comfortable environment in a building.

If you’re constantly surprised by high energy costs, replacing older windows and doors can help. New windows that have been specifically manufactured using energy-saving designs and materials install quickly and can have you enjoying the benefits of energy-efficient windows in your home, office, or business.

Steel Windows & Energy Efficiency

One of the most energy-efficient types of windows is thermally broken steel. While steel has been a standard for window frames since the middle of the twentieth century, these were often single-pane uninsulated windows. Modern steel windows feature double-paned construction, insulation throughout the frame, and sealed joints to prevent air leaks offering all the benefits of energy-efficient windows. Steel windows are also longer lasting than wood, fiberglass, or composite, which can crack or warp under ultraviolet light, and the rigors of rain, cold, and heat of outdoor weather allowing moisture to intrude and a building’s comfort to evaporate.

Steel windows can prevent this. Incredibly durable, steel is highly resistant to cracking from harmful elements and resists mold, vermin, and even damage from severe storms with its strength. Steel windows will not experience the cracking and warping common to other materials over time, which results in lower energy bills. This strength comes alongside reduced maintenance requirements due to using modern finishes and coatings on top of modern materials and seals. One of the things that can affect a window’s thermal breaking is how the glass is divided up, and there are options for how the light coming through a window is divided.


True Divided Lights (TDL) and Simulated Divided Lights (SDL) are two different ways of achieving traditional aesthetics. They refer to how the panes of glass are separated one from the other in a given door or window.

  1. TDL windows reflect the legacy design of early 20th-century architecture when individual panes of glass were “putty-glazed.” It features many individual panes of glass divided by thin strips of steel. It gives a hand-made or cottage appearance to the doors and windows. It does interrupt the thermal break as there is no way to insulate such thin pieces of metal. However, except for extremes of heat and cold, it is not a large interruption.
  2. SDL windows merely mimic the aesthetic. They are made with the appearance of individual panes of glass but are actually one large piece of insulated glass. The panes are divided by grilles added to the glass surface and aluminum “spacers” placed in the glass and behind the grilles. They maintain a consistent thermally broken envelope.

Both types are modern windows offer the benefits of energy-efficient windows. The difference between the two is insignificant for most homes. However, in properties where extremes of heat and cold are an issue or extreme humidity can cause a problem, property owners may prefer SDL. These windows offer a more consistent thermal profile and fewer potential areas for condensation to gather. In either case, they offer advantages over traditional windows or other window frame types.

What Are the Benefits of Energy-Efficient Windows?

While several factors go into determining the exact amount installing energy-efficient windows will save, it has been estimated by the U.S. Department of Energy that replacing single-pane windows with more energy-efficient insulated glass windows can save between $126 to $465 annually for an average 3-bedroom home. Over ten years, that’s up to $4,650 of direct savings. The savings can be substantially more on larger commercial properties with more windows and larger interior volumes.

Understanding R-Values & U-Factors

While searching for energy-efficient windows, you might wonder how to compare the various options available on the market. Energy efficiency is evaluated using R-values and U-factors. An R-factor measures a material’s ability to prevent heat loss, while the U-factor measures the amount of heat lost through a window or door unit. The lower the U-factor of a unit, the lower the amount of heat loss, and the higher the R-value is, the better the material is at stopping heat transfer. Both of these measurements can help determine which energy-efficient windows offer the most benefits.

While the benefits of energy-efficient windows are one of steel windows’ great advantages, there are many other benefits as well. Steel windows offer excellent security as well as great looks. The strength of steel resists severe weather, and intruders cannot easily access the interior of a property through high-strength steel windows. In addition, energy-efficient steel windows are customizable, enabling you to adjust their appearance to fit the style of your space. Whether you own a vintage-style home or are building an ultra-modern office space, steel windows suit almost every property.

Energy-Efficient Steel Windows From The French Steel™ Company

As a leading provider of highly energy-efficient steel windows for homes and commercial buildings, The French Steel™ Company is standing by to help match you with top-quality windows that ultimately help you reduce energy bills while still enhancing the overall appearance of your space.

Contact a French Steel™ consultant today to discuss the benefits of energy-efficient windows, how you could be maximizing the energy in your property, and the options available within your residential or commercial budget. We look forward to working with you.

French Steel’s doors and windows transform both the appearance and livability of a home. Their beauty is more than skin deep, combining the durability and timeless look of steel and glass with modern thermal breaking that improves the efficiency of home heating and cooling.

For more information on the energy-efficiency of steel windows, contact French Steel to start planning your home transformation.

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