Do you wonder why your house is too cold or too warm despite the climate and weather situation? Do you have to deal with ever-increasing energy expenses on warming and cooling? 

Let me introduce you to a guide to solar heat gain coefficient (SHGC), which allows you to modify energy-efficient windows to let in the proper amount of light and adjust the temperature in your rooms.

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Understanding Solar Heat Gain Coefficient (SHGC)

When the sun’s rays strike an object, such as a window, a remarkable amount of energy is absorbed and allowed to flow through, warming the item. So, it is the process of transforming solar energy on how much heat can be absorbed through a window to adjust according to the room temperature.

Window manufacturers use this term to describe how much solar radiation enters a structure through a door or a window.

How is it measured?

It is measured through how much heat is absorbed and released via the house’s windows. SHGC is a number that ranges from 0 to 1.

The lowest amount of heat entered is “0”. The “1” denotes the maximum quality of heat that can pass through a window.

Solar Heat Gain Coefficient and Climate Conditions

It’s a widespread misconception that the sun’s rays all perform the same thing: the sun provides us with various forms of solar energy. That’s why it’s crucial to know what a decent solar heat gain coefficient (SHGC) value is for windows and how these calculations affect your home.

The heating and cooling requirements of different climates are not the same. In the south, you’ll want a window that can block out as much heat as possible for the majority of the year. However, allowing heat is more important in the north, especially during the bitterly cold winter months.

If your area is warm, then windows with a low Solar Heat Gain Coefficient rating are more convenient.

Why are the ratings of solar heat gain coefficient (SHGC) important?

For homeowners, Solar Heat Gain Coefficient (SHGC) is a number that appears on many of the stickers that come with new windows by the National Federation Rating Council (NFRC). It is primarily governed by energy stars and influenced by several regional characteristics.

By reading the labels and numbers, you can determine how well that particular window will perform in your home. It is a number that indicates how much solar energy transports through a window.

For example, the lower the number, the lower the radiant heat allowed through the window, and the higher the number, the higher the radiant heat is allowed through the window. The number mainly depends upon the weather condition of the geographical location that one lives.

To clarify, imagine it is a sunny day; lower radiant heat would mean staying in the shade than the bright sunshine but sometimes standing in the sun might feel better when it’s cold outside. Similarly, the Solar Heat Gain Coefficient (SHGC) you choose depends on your house preference or geographical climate. When air conditioning is not an issue, a higher SHGC in the range of 0.30 to 0.60 is beneficial since the solar heat gain can assist warm the house during the winter months.

If air conditioning is utilized occasionally and cooling is an issue, use windows and skylights with an SHGC of less than 0.40.

The window’s U-factor, air leakage characteristics, visual transmittance, and condensation resistance are listed on the label. A combination of these factors determines a window’s total energy performance.

The National Federation Rating Council’s (NFRC) designations assist homeowners in selecting windows that best suit various applications and installations.

NFRC Label
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Why does Solar Heat Gain Coefficient (SHGC) matter?

The Solar Heat Gain Coefficient (SHGC) can inform homeowners how a particular vinyl window replacement will perform in various seasons, climates, and locales. As a result, you can anticipate the following advantages.

Safeguard against harmful UV Rays

Even while the sun has health benefits, it protects your skin from sunburn, premature aging, and skin cancer caused by UV radiation if your windows don’t have enough glazing or have low Solar Heat Gain Coefficient (SHGC) ratings. Furthermore, it helps to prevent aging and provides a safety net for your family members against harsh exposure to the sun.

Prevents the deterioration of furniture

When exposed to bright, direct sunlight regularly, your furniture, especially those made of wood and leather, can discolor, seem old, and wear out faster. Usage of SHGC not only protects your furniture but gives it an extra dosage of good looks for your furniture.

Make adjustments based on the weather

Solar Heat Gain Coefficient (SHGC) helps maintain a suitable climate adjustment in your house without extra electricity or equipment, whether your house is facing west or east, in the shadow, or on a sunny side.

Reduced energy and heating costs

The use of Solar Heat Gain Coefficient (SHGC) and climate adjustments aids in the reduction of excess energy, supporting a sustainable environment, as well as the cost of heating bills, providing you an extra amount of money to save. Energy-efficient Low-E storm windows can cut back anywhere from 12% to 33% every year.

Promotes environmental sustainability

As a green energy movement, we must understand conserving our resources, particularly when it comes to electricity. Windows play a role in insulating our homes as they require less energy to maintain a comfortable temperature during the hot summer months.

Wrapping up

Solar Heat gain coefficient (SHGC) is an effective solution to help with the climate conditions and provides an extra facility for homeowners to be more environment-conscious without the hassle. The breakthrough of technological advancement paves a step for developing energy to be more eco-friendly and a new renewable energy source to glide through.

(Last Updated on September 2, 2021 by Sadrish Dabadi)

Thinley Doma Ghale holds a Bachelor’s degree in Social Work from Kathmandu University. She enjoys writing articles on climate change animals and loves to travel and experience new ideas, places, meeting people, and learning from them. As a social science student, research has always been her area of interest.