Sustainable windows and doors are not only great for the environment, but also provide a pathway to higher levels of energy efficiency, lower utility costs, improved indoor comfort, and overall better building performance. The right combination of energy-efficient glazing, thermally optimized frames, and eco-certified materials can help to control heat flow, reduce energy losses, and create a healthier indoor space for occupants. With climate-centric building codes becoming increasingly rigorous over the coming years, selecting the proper materials will be crucial in achieving sustainable building objectives and designing high-performing, durable structures.
Introduction
Increasingly as society becomes more aware of global warming and the need for energy conservation and environmental responsibility, it is important to recognize that our decisions related to building design will have a major impact on the environment as well as the operating costs of the structures created. Windows and doors, while sometimes treated as secondary concerns when it comes to construction, are actually two very important parts of how a building functions throughout its entire life cycle. They play a key role in determining both the visuals and comfort of a given indoor area, as well as having a considerable effect on the amount of energy consumed, the quality of indoor air, and the overall sustainability of a building.
Why Material Choices Matter
Windows and doors are considered a critical part of a building’s envelope. This is the barrier that separates the inside of the structure from the outside world. When windows and doors do not function properly, this causes high levels of heat gain in summer and heat loss in winter, thus leading to increased demands for energy to heat and cool the building. In fact, the amount of heat gained and lost through windows can account for a significant portion of the total energy load of a structure.
An appropriate combination of building materials and technologies allows for significant improvements to the thermal performance of buildings as well as reduced energy consumption and better management of thermal loads year round. Therefore, there is an increasing emphasis on choosing materials and technologies that provide long term performance benefits, environmental benefits and operational cost savings, given the continuing evolution of building codes and issues regarding Sustainable Building Practices.
Materials That Enhance Energy Efficiency
1. High-Performance Glazing (Double & Triple Glazing)
Multi-pane glazing systems, like double and triple glazed windows, greatly enhance window efficiency by using multiple layers of glass with an air or inert gas space in between to reduce heat loss.
Benefits of Multiple Pane Glazing:
– Keeps heat in when it’s cold outside
– Limits heat gain when it’s hot outside
– Reduces Condensation
– Reduces Noise
All of these benefits equal lower energy bills, greater comfort, and a more consistent climatic environment year-round.
2. Low-Emissivity (Low-E) Coatings
Low-E coatings consist of extremely thin metal layers deposited onto window glass whereby the coating reflects back radiant heat into the structure during the winter months, while blocking out unwanted radio heat from the sun during summer months. In short, the use of low-E applied to glazing allows the temperature within the home to remain stable; thus reducing the need for heating/cooling equipment. Low-E glazing provides an avenue to enhance the thermal performance of windows while maintaining a high level of natural light.
3. Smart and Switchable Glass Technologies
Through advancement in technology, smart glass systems (electrochromic, thermochromic, and switchable) provide control over both solar heat gain and light transmission. Through the use of these glass types, users have the ability to change the tint density (or opaqueness) based on ambient weather conditions for improved energy management and occupant comfort.
Smart glass solutions improve energy efficiency while also reducing the need for blinds or shades and promoting healthier daylighting.
Frame Materials That Make a Difference
uPVC (Unplasticized Polyvinyl Chloride)
Because of the thermal insulating properties of uPVC, its ability to be recycled, and its long-lasting durability, it has become the primary material of choice for constructing windows and doors that are both energy-efficient and eco-friendly. In addition to these qualities:
- uPVC has lower thermal conductivity than most metal frames
- uPVC can withstand weathering and corrosion due to its synthetic nature
- There is very little maintenance necessary to keep a uPVC frame looking good for many years
- Heat and the subsequent need for cooling are both reduced using uPVC frames
The combination of these four factors makes uPVC an environmentally friendly and cost-effective choice for both residential and commercial building projects. The eco-friendliness of framed windows with uPVC components has been accepted as sound economic practice by many, if not all, builders.
Wood & Fiberglass Frames
Wood frames made from sustainably harvested trees have been shown to provide naturally occurring thermal insulating characteristics. Properly treated wood frames will produce good sustained thermal performance, similar to fiberglass composites, which exhibit superior thermal insulation, dimensional stability, and moisture and decay resistance, providing continued performance with little-to-no maintenance.
Both types of frames, when used in conjunction with high-efficiency glazing systems, can also support the overall sustainability of a structure.
Aluminum with Thermal Breaks
By design, traditional aluminum has been shown to conduct heat more quickly than most other materials, making it less than ideal for energy-saving applications. However, modern aluminum frames use a thermal break that separates the interior and exterior parts of the frame and consists of insulating material between them. This thermal break reduces the amount of heat that can be transferred through the frame and results in a more energy-efficient frame. Furthermore, modern aluminum frames still offer the inherent strength and recyclability of aluminum.
Sustainability Support Through Design Features
Air and Water Tightness
The air and water sealing of windows and doors is one of the most important design features to protect buildings from unwanted drafts and infiltration. When air leaks are minimized, there is a direct correlation between increased occupant comfort levels, and decreased requirement for heating/cooling. Higher quality sealing systems will minimize air leakage.
Installation & Orientation
Correctly installing energy efficient materials correctly during construction allows them to perform their intended function at maximum efficiency. Installing windows/doors in a manner that is consistent with the building’s orientation will enable optimal placement of windows/doors in order to achieve maximum passive solar gain and shading effects from the building itself, thereby reducing the overall energy load of the building.
Benefits of Installing Sustainable Windows & Doors
Reduced Energy Costs
Sustainable windows and doors help to increase the effectiveness of heating and cooling, thus decreasing costs associated with HVAC systems. Additionally, the installation of insulated windows saves energy usage and lowers monthly bills.
Increased Comfort and Indoor Air Quality
Sustainable Window and Door products create a more comfortable indoor environment by controlling excessive airflow from outside, keeping consistent indoor temperatures, and reducing unwanted exterior noise. The improved thermal efficiency of sustainable window systems will also improve humidity control and overall livability.
Less Impact on the Environment
The use of sustainable window and door products reduces the amount of energy consumed by HVAC systems, which results in a significantly decreased amount of carbon dioxide (CO2) being created. This will ultimately lead to important contributions towards decreasing climate change and achieving global sustainability goals.
Increased Value of Property
Sustainable windows and doors are more attractive to buyers and have increased desirability as sustainability is gaining momentum globally. Therefore, homes with sustainable windows or doors have an increased perceived value compared to homes without these features.
Meeting Green Building Standards
Compliance with the building specifications in both terms of Energy Star’s and NFRC’s Certification systems allows the customer to better understand the Window and Door options when selecting products based on their U value, Solar Heat Gain Coefficient, and Air Leakage. By selecting products that have a higher Energy ratings, Homeowners will be in compliance with local building regulations.
Closing Thoughts
Choosing smart materials to build Windows and Doors offers the homeowner, Builder and Architect the opportunity to design with Functionality, Beauty and Sustainable Principles to produce better-performing buildings and lower the needs for energy consumption. In virtually every industry the investment in Sustainable Windows and Doors is an investment in a more efficient, resilient and responsible way to build and live.
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