Conquer Wisconsin Weather with Superior Window Energy Efficiency
At Renewal by Andersen of Milwaukee, we know that true energy efficiency is about more than just the glass. It’s about whole-window performance designed to keep your home comfortable year-round.

The Big Picture: Why Whole-Window Performance Matters
When you are looking for energy-efficient windows, it is easy to get caught up in the details of individual components. Many companies tout specific features of their window components when discussing energy efficiency. However, at Renewal by Andersen, we focus on the big picture – the whole-window performance.
While individual components contribute to energy efficiency, it’s whole-window performance that’s most important. A truly efficient window requires the perfect combination of elements. We believe our outstanding whole-window performance is the result of a simple equation:
Framing Material + Glass + Professional Installation = Energy Efficiency and Long-Lasting Beauty
By paying particular attention to the window frame and glass – critical components for energy efficiency – and placing enormous significance on complete, professional installation, we ensure your new windows perform exactly as they should.

The Story of Fibrex® Material: Engineered for Excellence
Renewal by Andersen® products and patents have revolutionized the window and door industry for more than 100 years. We know windows and window materials. Our exclusive Fibrex® composite material wasn’t created overnight; it is the result of decades of rigorous testing and innovation aimed at solving the inherent flaws of traditional framing materials.
- Learning from the Past: In 1958, Renewal by Andersen’s parent company, Andersen Corporation, tested and rejected aluminum as a framing material. It conducted heat and cold, plus it could pit and corrode. Also in the 1950s, Andersen developed the first hollow vinyl window in the U.S. We liked the low-maintenance feature of vinyl, but concluded that it didn’t have enough structural integrity.
- The Breakthrough: In the 1970s, Andersen began experimenting with reclaimed wood fibers. In 1991, after decades of development and testing, Andersen patented and introduced Fibrex material, a composite of wood fibers and polymer.
- The Best of Both Worlds: Fibrex material combines the strength and stability of wood with the low-maintenance benefit of vinyl.
- Superior Insulation: Fibrex material has excellent insulating properties on par with wood, vinyl or fiberglass. Fibrex composite material insulates about 700 times better than aluminum, which transfers heat out of your home and allows outdoor temperatures to chill window areas inside.
- Unwavering Stability: Fibrex material is durable and reliable and much like wood, fiberglass and aluminum, it expands and contracts very little. However, vinyl can expand and contract significantly. Vinyl may cause cracks, bowing and air and water leaks. Windows made of Fibrex material will perform better in winter and summer than windows made of vinyl.
- Eco-Friendly: Renewal by Andersen windows made with Fibrex material also meet the strictest indoor air emission standards in the U.S. and are certified for recycled content. Renewal by Andersen and its parent company, Andersen Corporation, are the only window companies to receive Scientific Certification Systems (SCS) Indoor Advantage Gold™ certification for indoor air quality.
High-Performance Glass to Complete the Package
At first glance, all window glass may look the same, but not all glass performs the same. Each glass option incorporates a special low-emissivity (or “low-E”) coating that defines the performance and aesthetic characteristics of that offering. Essentially, low-E coatings serve as a type of thermal barrier that reflects energy back in the direction it came from meaning that heat stays in your home in winter, and heat is reflected away in summer.
We offer four distinct glass options to suit your home’s specific needs, climate, and architectural design:
- High-Performance Low-E4® glass: High-Performance Low-E4 glass is 45% more energy efficient in winter and 56% more efficient in summer compared to ordinary dual-pane glass. That can cut your energy bills by up to 25%.
- High-Performance Low-E4® SmartSun™ glass: High-Performance Low-E4 SmartSun glass is 49% more energy efficient in winter and 70% more efficient in summer when compared to ordinary dual-pane glass. SmartSun glass blocks 95% of harmful UV rays, which helps reduce fading on your carpet, drapes, artwork and furniture.
- High-Performance Low-E4® SmartSun™ glass with HeatLock® technology: Meets today’s stringent energy codes and requirements with near triple-pane performance in a dual-pane window. HeatLock glass reflects escaping heat back into the room.
- High-Performance Low-E4® Sun glass: Offers our highest rating against solar heat gain coming through your glass, helping keep your home cooler in warm weather.

The Details Matter: Renewal by Andersen optimizes the space between the two glass panes for the best thermal performance. Renewal by Andersen uses a low-conductivity spacer made of stainless steel that resists heat transfer better than aluminum spacers used by other manufacturers. A thinner spacer wall conducts less energy. Also, because stainless steel is so much stronger than aluminum, our stainless steel spacer can use less material and still keep the glass stable.

The Final Variable: Professional Installation
A window must fit well in the opening to provide long-term performance and energy efficiency. Renewal by Andersen replacement windows are custom made to precisely fit each window opening in your home, and they are installed by professional Renewal by Andersen installers. A good window can only perform well if it’s installed correctly.
Improper installation can easily occur if an installer cuts flashing incorrectly, uses the wrong sealant or does not insulate between the window and rough opening. Any of these things and more can keep your window from performing to the product’s fullest performance level.
We consider installation so important to a window’s performance that we back it in a written limited warranty.
Certified Efficiency and the Nation’s Best Warranty

NFRC Certified
Renewal by Andersen displays the NFRC label on all its certified windows. The NFRC label shows the whole-window U-Factor, Solar Heat Gain Coefficient (SHGC) and Visible Transmittance. This label means that the entire window unit has been rated and certified, not just the center of the glass or individual components. NFRC certified U-Factor values are the only measure of whole-window thermal performance.

ENERGY STAR® Partner
Every ENERGY STAR® qualified window and door must meet or exceed energy efficiency criteria set by the U.S. Department of Energy. Most Renewal by Andersen windows with select glass options are ENERGY STAR® certified in all climate zones of the United States.

Nation’s Best Warranty
Renewal by Andersen has the Nation’s Best Warranty coverage. It is fully transferable and covers Fibrex material, installation, hardware, and glass. It is the only warranty among top selling window companies that meets all of the following requirements: easy to understand terms, unrestricted transferability, installation coverage, labor coverage, geographically unrestricted, coverage for exterior color, insect screens and hardware, and no maintenance requirement.
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Ready to Upgrade Your Home’s Comfort and Efficiency?
When you choose Renewal by Andersen window replacement, you will help improve comfort with low-maintenance, energy-efficient windows. Let us help you find the perfect solution for your Milwaukee home.



