When it comes to choosing energy-efficient windows, there are several technical specifications that you should be familiar with. Understanding these specs will help you to make an informed decision about the best windows for your home or building.
Energy Rating: The Energy Rating (ER) is a measure of the window's overall energy efficiency. The ER takes into account several factors, including the U-factor, solar heat gain coefficient, and air leakage rate.
U-factor: The U-factor measures how well the window prevents heat from escaping. A lower U-factor indicates better insulation and greater energy efficiency. U-factor is expressed in units of Btu/hr•ft2•°F.
R-factor: The R-factor is the inverse of the U-factor and measures how well the window prevents heat from entering the home. A higher R-factor indicates better insulation and greater energy efficiency. R-factor is expressed in units of hr•ft2•°F/Btu.
Argon gas: Argon gas is sometimes used to fill the space between the panes of double or triple glazed windows. Argon gas is a better insulator than air and can help to reduce heat transfer through the window.
Low-E coating: Low-E (low emissivity) coatings are applied to the glass of energy-efficient windows to reflect heat back into the home and prevent it from escaping. Low-E coatings can also reduce the amount of UV radiation that enters the home, protecting furniture and other objects from fading.
Solar heat gain coefficient (SHGC): The SHGC measures how much heat is transmitted through the window from the sun. A lower SHGC indicates less heat transmission and greater energy efficiency.
Transmittance: Transmittance measures how much visible light passes through the window. A higher transmittance indicates greater visibility and more natural light entering the home.
Positive and negative pressure: Windows are subject to both positive and negative pressure due to wind and air pressure differences inside and outside the home. Windows with better seals and stronger frames can better resist these pressures, reducing the chance of air infiltration.
Water penetration resistance: Windows are tested for their ability to resist water penetration during heavy rain and other weather conditions. Higher resistance to water penetration can help to prevent leaks and water damage.
In conclusion, understanding the technical specifications of windows can help you to choose the most energy-efficient and effective windows for your home or building. Pay attention to the U-factor, R-factor, SHGC, and other factors when choosing your windows, and consider opting for energy-efficient features such as low-E coatings and argon gas fill. By choosing energy-efficient windows, you can reduce your energy bills and improve the comfort and value of your home.