Not surprisingly, wood clad and fiberglass window frames rated the highest. (These replacement windows also carry the highest price tags.) These window frame materials are better at keeping out the rain, wind and elements. Each window was put through a week of extreme temperatures to see how the window expanded, contracted and flexed with temperature and condition changes. Each window was then tested for water and air leakage. Windows that exhibited little or no change in performance from the start to finish were ranked highest.
Vinyl is less expensive and convenient
Vinyl replacement windows account for nearly 50% of the market because they are reasonably priced and maintenance-free. However, vinyl windows will let some air seep through, especially in colder climates. In addition, vinyl is less attractive than wood clad and is not able to be stained or painted to match or compliment a home's exterior color.
Replacement Window Ratings
When comparing the same type and style of window from different manufactures or even different lines from the same manufacturer, you have probably noticed one thing: no two windows are exactly the same. Don't panic! There's no need to resort to anything as drastic as defenestration - or jumping out of a window. In order to ensure that your replacement windows will provide you with great home comfort and energy cost savings, the National Fenestration Rating Council or NFRC and Energy Star provide a useful rating system for evaluating window quality and energy efficiency.
It can be difficult to compare claims made by different window manufacturers, mainly because they often use different window measures and rating terms to sell their products. For instance, some may use center-of-glass R-value and shading coefficient, while others use Windows 10 Home
-window U-factor and solar heat gain coefficient. Fortunately there is now one place to look that has standardized ratings for windows - NFRC. The National Fenestration Rating Council (NFRC) is a nonprofit coalition of manufacturers and window experts that has set standards for testing and labeling windows.
The National Fenestration Replacement Council
The NFRC has developed a fairly comprehensive window performance/ energy star rating where they provide uniform and definitive benchmarks by which all window companies must now measure a window's energy performance. You can easily compare windows from different manufactures or different lines from the same producer because the information is handily and precisely presented in an easy to understand summary. However, you should be forewarned that windows are evaluated and rated when they are new and therefore long-term resilience is not taken into account. In addition, the Council does not perform studies on already installed windows or their history.
The NFRC Window Replacement Rating System
The key element to the National Fenestration Replacement Council rating system is a window's U-factor. The NFRC gives each window a U-factor rating. The first number after the words U-factor is the rating that's appropriate for residential purposes. It will be marked AA or Residential. The U-factor marked BB or Non-Residential is for commercial window applications. The U-factor on the NFRC label always refers to the whole window. To make sure you are comparing apples to apples, ask for the NFRC ratings even when there is no label on your window replacement. Also, be sure to use the same size windows for comparison, because the ratio of glass to framing affects the result.