What’s Solar Heat Gain Coefficient and Why is it Important?

When you invest in replacement windows, you want them to be energy efficient and protect your home from the outside weather. This includes shielding your home from the sun’s harmful rays. Knowing a window’s solar heat gain coefficient is the key.

What on Earth is solar heat gain coefficient, also known as SHGC? If most homeowners have never even heard about it, how important can it really be? You’re about to be shocked because it effects your home’s temperature and can prevent your belongings from being damaged.

solar heat gain coefficient

We’ll go over everything about SHGC from what it is to how it effects your home. When you do need replacement windows, you’ll know exactly what you’re looking for.

What is Solar Heat Gain Coefficient?

The question on everyone’s mind is, “What is solar heat gain coefficient?” It is the industry standard term for the amount of solar radiation admitted through a window. That probably doesn’t answer your question.

In short, it’s the amount of ultra violet rays that are able to pass through your window. Having less UV rays pass through your window doesn’t mean you’re blocking sunlight as well. UV rays make your home warmer and can damage your floors walls and furniture.

How Do You Measure It?

Now that you know what it is, you’re probably wondering how it’s measured. SHGC is found by multiplying the shading coefficient (SC) by 0.87. The lower the number, the better solar heat gain coefficient your window has.

That answer probably gave you more questions than answers. What in the world is shading coefficient? It’s the old metric that the window industry used before moving to SHGC. It determines the thermal performance of a glass unit.

beautiful windows in a living room

How do you find the SC? It’s the ratio of solar gain passing through a glass unit to the solar energy passing through 3mm clear float glass. Much like SHGC, the lower the number, the better shading coefficient.

This all sounds so complicated, but have no fear. Most companies display a replacement window’s SHGC so you don’t have to guess. You know exactly what you’re getting with a window before you buy it.

There Are Many Reasons It’s Important to Know Your SHGC

Solar heat gain coefficient is extremely important when purchasing replacement windows. It can be the difference between being happy and comfortable and being absolutely miserable. It’s especially important when you live in an area with erratic weather patterns such as the Midwest.

We’ll explain the benefits of getting windows with low SHGC below.

Keeps Your Home Cooler

One thing solar heat gain coefficient effects is the temperature of your home. While it doesn’t have the same effect as u-factor, you’ll notice the difference immediately.

SHGC determines the solar radiation that’s admitted through the window. Obviously, the more light that gets through your window, the warmer your home is and your window’s solar heat gain coefficient will be larger.

By simply looking at your replacement window’s SHGC, you’ll be able to determine the amount of solar radiation that enters your home. This will help lower your home’s overall temperature.

Prevents Ultra Violet Rays From Getting Into Your Home

Homeowners often overlook the damages that can be caused by UV rays. Since your walls, floor and furniture aren’t getting direct sunlight, they’re in no real danger, right? Wrong!

walls, floor and furniture can be faded

If your windows have a high SHGC, more UV rays will get into your home. UV rays can fade colors and damage your floors, walls and furniture. It can cost hundreds of dollars in damages if you have to replace everything.

You’ll Save Money

Aside from saving money on damages, windows with low SHGC can save you money another way. You already know that allowing more solar radiation into your home can effect its temperature. It’ll also effect how much power you’ll use.

Your air conditioner runs on electricity. When you have energy efficient windows with a low SHGC, reaching your desired temperature is no problem. However, if more solar radiation is getting into your home, you put extra stress on your air conditioner. It uses more power to keep your home cool and comfortable. It’ll be reflected on your monthly electric bill.

Look for the Energy Star Sticker

Energy Star Certified products are clearly labeled with a square blue sticker. You’ve probably seen it on kitchen appliances, TVs and your washing machine. It’s awarded to products that are the best of the best in energy efficiency.

Windows can also earn an Energy Star sticker. There are a lot of factors that go into an Energy Star window – double or triple pane, a good u-factor and overall insulation. One factor that’s often overlooked is its solar heat gain coefficient. Since it can lower your energy usage, it plays a role in whether or not your windows are Energy Star Certified.

Knowing Solar Heat Gain Coefficient Can Help You Get the Perfect Replacement Windows

No one wants windows that aren’t energy efficient and allow tons of solar radiation into your home. It’ll make you uncomfortable and can even damage your floors, walls and furniture.

Knowing what SHGC is will help you get the perfect windows for your home. Since many companies post all of the numbers of their replacement windows, knowing what they mean is most of the battle. After reading this article, you have the upper hand when starting your window replacement project.

Feldco offers windows with a low solar heat gain coefficient. We make it our goal to have the best windows for Midwest homeowners. Having a low solar heat gain coefficient is just one of the many features that make our windows the best.

Get a free quote now and see why over 400,000 homeowners have trusted Feldco. With 40 years of experience, you won’t find anyone better in the Midwest.

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