Steel Window Energy Efficiency
October 10, 2010
The most-common use of steel windows today is in industrial or commercial buildings. Steel is tough and secure. Some homeowners prefer steel frames for residential use because of their durability and price. And with their slender profile, steel frames can cut down on the required width of the glass in your windows. However, steel windows energy efficiency ratings are consistently lower than fiberglass, vinyl, and wood.
Evaluating Energy Efficiency
Energy efficiency is typically measured by the ability of the window product to insulate, retain interior temperatures, and block outside heat generated by sunlight. When you read the manufacturer's label, you can compare steel windows energy efficiency against the ratings earned by other products. The u-factor measures heat loss. The lower the rating number, the greater the energy efficiency for the window.
Solar Heat Gain Coefficient (SHGC) measures the ability of the window to resist outside heat from the sun. Again, the lower the number, the better. Air leakage ratings are very important when it comes to a steel window's energy efficiency.
How Do Steel Windows Measure Up?
Since windows in your home may account for as much as 15 percent of overall heat loss, steel may not be your best choice for frames. One reason is that steel frames may fit correctly at first, but over time the sashes can crack, allowing energy to escape. The windows can come out of alignment or build rust over time, compromising their insulating properties.
If you have a historical home style that calls for steel frames, be sure to use windows that offer the greatest affordable efficiency ratings.