Understanding Window Energy Efficiency
Window energy efficiency is one of the most important aspects of buying windows. It is crucial for buyer’s to have a keen understanding of the ratings, how they differ, and what they mean for their own project. For example, an energy efficient window in one climate may not be energy efficient at all in another. Those shopping for energy efficient windows also may be subject to strict regional requirements, while others may not.
In this article we will give you a comprehensive overview of window energy efficiency and how your requirements, region, climate, and energy ratings have to work together for window energy efficiency.
Window Energy Efficiency Requirements
When it comes to choosing energy-efficient windows, you should first identify what requirements your local building department is going to enforce for window thermal performance. Window energy efficiency requirements are generally outlined in your building plans, if you have them, or by your local building department. In some situations, the building department may not require the most energy efficient windows, or even any ratings at all – in that case, you would decide which energy package to choose based on your local region’s climate. Window energy ratings are tested and certified by the National Fenestration Rating Council (NFRC), and all rated windows will include an NFRC label.
Region and Climate Sustainable Window Technology
In addition to any requirements set by your building department, the region and climate you live in will set the general guidelines for the optimal window insulation efficiency. With climate having the ability to change quickly based on geography, it is important to understand what is needed in your particular regions climate which can be broken down to two ratings; U-Factor and Solar Heat Gain Coefficient (SHGC). While all climates can benefit from a low U-Factor, SHGC can be a bit more climate specific. Generally speaking a predominantly cold climate will benefit from a SHGC between .32 – .40, whereas a hot climate will benefit from as low of a SHGC as possible. In the next sections we will discuss the U-Factor and SHGC.
U-Factor (Insulated Windows)
U-Factor: The technical definition of U-Factor is “the rate at which a window, door, or skylight conducts non-solar heat flow, generally expressed as Btu/hr-ft2-*F.” In layman’s terms, this means that the U-Factor measures the insulating value of the window. Whether it is hot or cold outside, this measures how much heat transfers through the window, through means other than from the sun’s rays (we will discuss this in SHGC). It is important to know that the lower the U-Factor, the more energy efficient the window will be in terms of insulation, thus a lower U-Factor means a better insulated window, regardless of climate.
Solar Heat Gain Coefficient – SHGC (Heat Blocking Windows)
The technical definition of Solar Heat Gain Coefficient, or simply SHGC for short, is “the fraction of solar radiation passed through a window, door, or skylight.” In other words, the SHGC measures how much heat is blocked directly from the sun’s rays. This means that a lower SHGC will block more of the sun’s rays that would otherwise enter the home resulting in heating the inside of the house. Unlike U-Factor, where a lower rating is universally better, the SHGC, as stated before, is a little more dynamic based on your particular climate. For example, in a hot climate such as Phoenix, Arizona – you will want as low of a SHGC as possible to block out as much heat as possible. However, in a colder climate, such as Colorado, you may want the SHGC in the middle to high range so to allow some passive heating. If your home is specifically designed to take advantage of passive heating, you can even have a very high SHGC above .50, and with today’s technology, it is possible to have both a Low U-Factor and a High SHGC to take advantage of passive heating.
A big factor to take into consideration, if you live in a cold climate, is what do your summers look like? Many places battle the cold for months on end – but still receive many hot days during the summer. So, even if you are mainly concerned with the cold, if you have a very high SHGC, during those handful of hot sunny days, you may end up with too hot of a temperature inside the house if your SHGC is too high.
Now that we have a better understanding of how region, climate, and requirements must work in harmony with the heat blocking and insulating window properties, our next step is to explore the components that get us where we need to be. To learn more about the energy efficient window components Milgard uses, as well as Milgard energy packages visit our Energy Efficient Windows blog.
Replace your Windows with Milgard Energy Efficient Models
At Construction Windows we exclusively offer the Milgard Window brand. We are a Top Milgard seller who provides completely customized window solutions for our customers.
Milgard is renowned for its commitment to producing energy-efficient windows that combine cutting-edge technology with exceptional performance. Their energy-efficient window solutions are designed to provide homeowners with a comfortable indoor environment while reducing energy consumption and lowering utility costs. Here are some key features and benefits of Milgard Energy Efficient Windows:
- High-Quality Materials: Milgard utilizes top-grade materials to manufacture their energy-efficient windows, ensuring durability, longevity, and superior performance. These windows are built to withstand various weather conditions while maintaining their energy-saving capabilities.
- Advanced Insulating Glass: Milgard incorporates advanced insulating glass technologies in their windows to enhance energy efficiency. Their dual-pane glass options feature low-emissivity (low-E) coatings, which help to minimize heat transfer and block harmful UV rays. This improves thermal insulation and prevents heat loss during cold seasons while reducing heat gain in warmer climates.
- Gas-Filled Chambers: Many Milgard Energy Efficient Windows feature argon gas fills between the glass panes. This inert gas provides additional insulation and reduces heat transfer, further enhancing the energy efficiency of the windows.
- Glass Spacer Technology: Milgard integrates spacer technology into their windows, which improves thermal performance and reduces condensation. This innovative design minimizes heat loss around the window edges, contributing to overall energy savings and increased comfort.
- ENERGY STAR® Certification: Milgard Energy Efficient Windows meet or exceed the rigorous energy efficiency criteria set by ENERGY STAR®, a program developed by the U.S. Environmental Protection Agency (EPA). This certification ensures that Milgard windows deliver significant energy savings and meet strict performance standards.
- Customizable Options: Milgard offers a wide range of window styles, sizes, and designs to suit various architectural preferences and individual needs. Homeowners can choose from different frame materials, such as vinyl, fiberglass, or aluminum, to match their aesthetic preferences while maintaining energy efficiency.
- Sound Control: In addition to their energy-saving features, Milgard Energy Efficient Windows also provide excellent sound control. The windows are designed to reduce exterior noise infiltration, creating a quieter and more peaceful indoor environment.
Investing in Milgard Energy Efficient Windows not only enhances the energy efficiency of your home but also contributes to a more sustainable future. By reducing energy consumption, these windows help to mitigate environmental impact while providing homeowners with year-round comfort and potential cost savings.
Start Customizing Your Energy Efficient Windows Today
Window energy efficiency is a crucial consideration when purchasing windows. Understanding the ratings, regional requirements, and the impact of climate is essential for making informed decisions. The U-Factor and Solar Heat Gain Coefficient (SHGC) are important metrics to consider, as they determine the insulation and heat-blocking capabilities of windows. Finding the right balance between these factors ensures optimal energy efficiency for your specific needs and climate conditions.
At Construction Windows, we make the window buying process easy. With our convenient online window builder you can create custom Milgard windows and specify your energy efficiency needs. Not sure where to start? Chat with a window expert today!