What Is a Good Solar Heat Gain Coefficient (SHCG) Rating and U-Factor for Windows in Sunny Sacramento?
Sacramento is at its best during the sunny summer with our beautiful weather and even more beautiful countryside showcasing the rolling hills of the wine country. Being one of the sunniest cities in the country has a lot of advantages, especially since Californians all seem to strive toward using alternative and environmentally-friendly energy sources like solar power. Homes can really take advantage of all that sunshine by installing solar panels—and by designing their home windows to utilize as much natural light as possible. But when it comes to windows, Sacramento homeowners also have to consider the amount of heat that gets into our living spaces along with all that daylight.
It’s a common mistake to think that the sun’s rays all do the same thing: We actually get several different types of solar energy from the sun. That’s why it’s important to understand exactly what is a good solar heat gain coefficient (SHGC) or U-factor rating for windows in Northern California—and how do these calculations actually affect your home.
While these two ratings both quantify the heat gain and solar energy that your windows absorb and transmit, meaning both are equally as important to the energy efficiency of your windows, there are some differences. And understanding what makes each unique is what will ultimately help lower your energy bills—and your impact on the planet.
What Do SHGC and U-Factor Ratings Mean for Your Home’s Windows?
Windows remind me of how we used to think about going to the beach and laying in the sun. People believed that getting a suntan was healthy for them, while it was actually damaging their skin. While sunlight does provide us with some Vitamin D, it also has a lot of harmful rays. Just like our skin, our homes have to be protected from Northern California’s extreme sun exposure. What does the protection of SHGC and U-factor ratings mean for your home? Well, let’s look at several ways that too much of the gorgeous Sacramento sunshine can be bad for it:
- It will fade furniture: Over time, solar rays that come in through your window can fade furnishings. UVA and UVB rays from the sun are the main culprit. Windows with low-e film can prevent much of the damage from these types of rays.
- It can warm your home above comfort levels: Windows with minimal insulative protection can gain a large amount of heat. The average summer high temperature in Sacramento is around 90 degrees Fahrenheit, and all that hot air is trying to make its way into your home. One of the main ways that heat is transferred is through window panes and around frames, but well-insulated double pane windows with low U-factors will prevent much of the transfer of heat, and are the best replacement windows for Sacramento homes.
- It can run up electric bills: Heat gain through windows with little insulation can be one of the major factors driving up your electric bills because your air conditioner will have to work overtime to cool this air down. Windows with insulation and protective films can prevent the solar radiation, i.e. heat, from the sun from heating up the air in your home in the first place.
What Is a Good Solar Heat Gain Coefficient (SHGC) and U-Factor?
Your windows can get graded for energy efficiency just like a report card from school. And, just like how a school report card measures your understanding of school subjects, energy efficiency rating systems measure your windows’ ability to help your home conserve its energy.
The National Fenestration Rating Council (NFRC) is the governing body responsible for testing windows based on their energy performance, and then providing them with certifications based on the following ratings:
- What is a good U-factor rating? The U-factor rating measures how much heat is transferred through the window in Btu/h.ft², with the best rating or values between 0.17 and 0.30 in a warm climate like Sacramento’s. The lower the value of the U-factor, the more energy-efficient your window is, so the closer to the 0.17 Btu/h.ft² value the better. To be Energy Star rated, windows in our climate zone must have a good U-factor of 0.30 or less.
- What is a good solar heat gain coefficient (SHGC) rating? The solar heat gain coefficient (SHGC) measures how much solar radiation passes through your window and is released as heat into your home. It has rating values of 0 to 1, and just like the U-factor rating, lower values are better for hot climates like the one in Northern California. To be Energy Star rated, windows must have a good SHGC rating of 0.25 or less.
The Advantages of Energy-Efficient Windows
In a city like Sacramento where both the solar radiation from the sun and the high temperatures have to be considered, it’s important to look at how your windows are rated. The sun and heat can be a double whammy in the summer months when energy bills are typically at their highest. That’s why it’s so important to hit back with well-insulated windows that have both low U-factor and SHGC ratings. Three advantages of energy-efficient windows are:
- Energy savings: Windows work with the envelope of your entire home to insulate it, and the more windows you have, the more the integrity of your home’s seal depends on them to be good insulators. Having well-insulated windows with low U-factors and low SHGC ratings will prevent outdoor heat from infiltrating your home, giving your air conditioning unit a rest. Not only does this keep your AC to run at its optimal performance, but also helps keep your home from using excessive electricity from the grid.
- Lower power bills: Well-insulated windows help your home use less energy to heat and cool itself, which means you pay less each month on your electric power bill. In fact, installing energy-efficient low-e storm windows can save you 12%-33% annually. And, double pane windows will last longer, requiring fewer repairs and replacement over time. They can also extend the lifespan of your air conditioner by keeping it from overworking.
- Increased comfort levels: If you’ve ever sat in a single pane window seat on a hot day, you know how important insulation is to hold off the sun beating down during the day. An insulated window can block radiation rays and prevent heat gain, keeping your indoor space cool while still allowing all that bright sunshine inside. Windows with low-e coatings allow natural light into your home while blocking solar radiation that wants to heat up your home.
As a city on the forefront of the green energy movement, Sacramento residents know how important it is to conserve our resources, especially when it comes to energy. Windows play a big part in insulating our homes so they use less energy to stay temperature controlled during the sunny summer months. We live in the third sunniest city in the United States. Having well-insulated windows that feature good U-factor and SHGC ratings is guaranteed to play a role in how much energy we use—and how comfortable our homes stay.
All that sunshine and the high temperatures of the summer months mean that windows need to have a low U-factor as well as a low SHGC rating to be the most energy-efficient. A good U-factor ensures that all that hot air outside doesn’t make its way through your windows, while a good SHGC rating will block the solar radiation from the sun from heating up the inside of your home. Sacramento prides itself in being energy conscious, so it’s important for you to know how to choose the right energy-efficient windows when buying new ones for your home.
If you’re in the market for new windows for your Sacramento home, ensure they have good U-factor and SHGC ratings. Bell Brothers offers energy-efficient, custom made windows to fit your homes frames—and style.
Image courtesy Unsplash user Freddie Marriage