Replacement Window Ratings Explained

Replacement Window Ratings Explained
For Your Holland, PA, Home

Your Guide To Choosing The Right Window
Ratings For Your Home

When shopping for new window for your Holland, PA, home, there are many important classifications and ratings to consider. These window ratings are essential to knowing exactly what you’ll get from the products you choose. The problem is they’re not always easy for everyone to understand, making the decision process that much more challenging.

Several important window ratings are used to describe replacement window, including the following:

  • Solar heat gain coefficient
  • Visible transmittance
  • Air leakage
  • U-factor
  • Condensation resistance
  • Design pressure
  • UV percentage
  • Sound transmittance class

We’ll explain what each of these means and how to choose the best option for your home. Read on for everything you need to know about essential window rating information.

Solar Heat Gain Coefficient

The amount of heat that passes through a window is called the solar heat gain coefficient (SHGC). It is a number between 0 and 1, with a lower number indicating less heat is transferring across the window. Essentially, the lower the SHGC, the better for your home.

An easy way to think about this is to consider a hot summer day. The SHGC can be defined as how much of that heat gets absorbed and transferred across the window. Simply put, SHGC can be considered heat.

Visible Transmittance

The measure of how much light gets transmitted through a specific window is its visible transmittance (VT). With this window rating, most Bucks County homeowners want a higher number, as it indicates more light will be transmitted through the window. This allows for maximizing the use of natural lighting throughout the different rooms in your home.

VT scores range between 0 and 1. Double and triple-pane window typically have VT scores between 0.30 and 0.70. Several factors affect a window’s VT, including the following:

  • Coating or tint installed on the glass
  • Window grids or muntins
  • Window frame and sash thickness

Because of these factors, you must compare similar window styles. For example, you cannot compare single-pane window styles that have grids with triple-pane options without grids because you will not obtain an accurate comparison.

Air Leakage

While you expect your window to be draft free, there are some situations in which small amounts of air will pass through. The window’s air leakage or air infiltration is the measurement of this air transmission.

It specifically measures the quantity of air that can pass through the window in a one-minute span when subjected to continuous 25 mph wind.


This type of situation will rarely occur in everyday situations. However, to receive Energy Star certification, window must receive an air leakage rating below 0.30 cfm/sqft. In general, you want to see the lowest number possible, which indicates higher energy efficiency.


The U-factor of a window is determined by the National Fenestration Ratings Council (NFRC) and is a measurement of how well the window is able to insulate a home. The general range you should be looking for is between 0.20 and 1.20 for an ideal U-factor, with a lower number indicating better performance.

The NFRC takes into account all parts of the window, including the frame, glazing, and spacers. Other measurements simply focus on the glass, not providing an accurate picture of the window’s total insulative properties.

The better your window can insulate, the better your total home comfort will be. Your heating and cooling systems won’t have to work as hard to maintain the proper indoor temperature, regardless of the weather outside. Because of this, you can associate the U-factor with insulation.

Condensation Resistance

Condensation can be an unsightly problem on window when the temperature changes outside, cooling the glass. Condensation resistance (CR) measures how well your new window resist the formation of condensation and is another feature to consider when looking for energy-efficient options.

The measurement for CR is taken at 30%, 50%, and 70% relative humidity indoors while the outdoor temperature is 0℉ and the wind is a constant 15 mph. Its range is from 0 to 100, with the higher numbers indicating better CR. In general, a good CR is between 30 and 80.

Design Pressure

The window’s physical strength is measured by its design pressure (DP) – higher ratings mean stronger window. Understanding this number is essential because you can run into problems when

buying window for your Bucks County home. Some sellers will peddle thicker window frames as stronger when they don’t have a good DP rating.

The typical DP range for window is between 15 and 50. However, it is possible to find them with higher ratings. When looking for the strongest window, consider the DP rating.

UV Percentage

UV rays come in three categories: UV-A, UV-B, and UV-C. UV-A is the least harmful of the three and the type of UV rays that window generally allow to pass through. Windows with a lower UV percentage allow much fewer rays to pass through, especially the harmful UV-B and UV-C variety.

You want window with a low UV percentage – UV rays can increase the heat in your home and severely damage your furniture by fading it. A good UV percentage can increase your energy efficiency and protect your belongings.

Sound Transmission Class

If you live in a noisy neighborhood, you’ll want to pay attention to the sound transmission class (STC) rating of the window your buy for your Holland, PA, home. The higher the rating, the better sound-dampening effects your window will provide.

There are window designed for average-level noise and those specifically for noisy areas. Additionally, choosing a triple-pane window doesn’t always mean you’ll get the best noise reduction – it depends on the quality of the glass used in production.

When You Want Replacement Windows With The Best Ratings For Your Holland, PA, Home, Turn To Rosenello’s Windows

Here at Rosenello’s Windows, we’ve done your homework for you and found the best window for your Holland, PA, home. We settle for nothing less than the best for our customers.

We’re the local window installer with values that ensure your replacement window project is completed the right way the first time. We focus on every detail that other companies are prone to skipping over.

Call Rosenello’s Windows today at (215) 244-3993 to schedule a free estimate.

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