What Is the Solar Heat Gain Coefficient?

What Is Solar Heat Gain Coefficient? (It’s Importance)


In the quest for sustainability, energy efficiency in buildings has grown to be a crucial factor. The solar heat gain coefficient (SHGC) is critical in maximizing energy efficiency.

We shall examine the idea of SHGC, its significance, its connection to climates, and its comparison to similar words in this article. Let’s start!

How much solar heat gain is there?

The solar heat gain coefficient (SHGC) governs how much solar radiation gets through a window or glazing system. It shows how much solar heat gain passes through a window and into the structure. The SHGC takes into account both direct and absorbed solar radiation that’s re-emitted as heat inside the building.

SHGC: Why Is It Important?

The SHGC of a window significantly influences the energy efficiency and comfort levels inside a building. Windows with a lower SHGC value send less solar heat, which can reduce the cooling load placed on air conditioners during the sweltering summer. Windows with an optimized SHGC help to reduce energy consumption, raise occupant comfort, and rely less on mechanical cooling by effectively limiting solar heat gain.

Climates and Solar Heat Gain Coefficient:

Depending on the climate where a building is located, windows should have excellent SHGC value. In warmer climates, windows with lower SHGC values are often preferred to minimise the entry of excess heat and reduce cooling requirements. On the other hand, windows with higher SHGC ratings can be advantageous in colder areas since they permit more solar heat gain, which reduces the need for heating during the winter.

Is the SHGC the same as the shading coefficient?

Despite their connection, the shading coefficient (SC) and SHGC are not the same. The shading coefficient only calculates the direct solar heat gain, whereas the SHGC assesses the entire solar heat gain through a window. SHGC provides a complete picture of a window’s performance by accounting for direct, absorbed/re-emitted solar heat.

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Which solar heat gain coefficient for windows is the best?

The environment, building orientation, and intended energy efficiency objectives all play a role in determining the appropriate SHGC for windows. Local building codes, energy rating programmes, or consultation with energy specialists are all options to determine the appropriate SHGC value for a given project. Generally, an SHGC value of 0.40 or lower is advised for energy-efficient designs in hot areas, whereas a value of around 0.55 may be more appropriate in cooler climes.

What distinguishes U-Value from SHGC?

While the U-value evaluates a window’s thermal conductivity, SHGC concentrates on solar heat gain. The U-value is a measure of the rate of heat transmission through a window, taking into account both conduction and air leakage. A lower U-value indicates more excellent insulation and less heat loss. When choosing energy-efficient windows, it’s crucial to consider both SHGC and U-value because they each address a separate component of a window’s performance.

What is the PF value for the solar heat gain coefficient?

There is little knowledge available concerning this particular coefficient as of 2023. However, to maintain accurate information regarding solar heat gain coefficients, staying current with the most recent research and industry standards is crucial.

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(FAQs)-Frequently Asked Questions

There is only one way to calculate the solar heat gain coefficient.

Strict testing following acknowledged standards, such as the National Fenestration Rating Council (NFRC) in the United States, is used to calculate the solar heat gain coefficient. Under controlled circumstances, testing entails monitoring solar radiation transfer and heat gain.

Is it possible to increase the solar heat gain coefficient?

Yes, there are several ways to increase the solar heat gain coefficient of windows, including the use of low-emissivity (Low-E) coatings, spectrally selective glazing, double or triple glazing, and the addition of shading fixtures like blinds or awnings.

Do SHGC-related building codes or regulations exist?

Numerous building regulations and energy rating systems outline the maximum permissible SHGC values for windows in various climate zones. Buildings must adhere to these guidelines to guarantee that they are energy efficient.

Can SHGC parameters change to suit specific requirements?

Depending on the requirements of a particular project, certain window manufacturers provide alternatives for tailoring SHGC values. With these options, builders, and planners can make structures with the good possible power efficiency.


Understanding the solar heat gain coefficient is essential to develop energy-efficient buildings with high-performing windows. The amount of solar heat that enters a building through windows is determined by the SHGC value, which affects both energy use and occupant comfort.

Selecting windows with an adequate SHGC for the local environment and building orientation will result in the greatest energy efficiency.

This will also lessen the need for mechanical cooling systems. To make informed choices about solar heat gain coefficients and window design, stay current on industry advancements, and speak with professionals.

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