At a time when energy costs are increasing with each passing year and the effects of climate change are becoming more apparent, there is a need to be more energy efficient. In our homes, this means reducing the amount of energy we consume for heating and cooling. Homeowners are called upon to invest in everything energy efficient, including windows, to achieve overall energy efficiency.
With the above in mind, we will explore the energy efficiency of unplasticized polyvinyl chloride, better known as uPVC windows, with the goal of educating you on the merits of using this type of window if you’re after energy efficiency.
The U Value Of uPVC Windows
The u-value of a window is the measure of thermal transmittance (how easily heat passes through the window material, causing heat gain during summer and heat loss during winter). Generally, the lower the u-value, the better the window. While having a low u-value does not speak to the overall energy efficiency of the window, it’s a good indicator that the window is a high performer when considering energy efficiency.
uPVC windows have some of the lowest u-values of any window materials on the market. Many of the uPVC windows have a u-value of lower than 1.6 W/m²K, with triple-glazed uPVC widows having a u-value ranging between 0.64 to 0.94 W/m²K. Metal and wooden windows do not typically achieve such low uPVC values.
How uPVC Windows Achieve A Low U Value
Here are some of the ways through which uPVC windows achieve low u-values.
#1. Optimal Thermal Efficiency – Modern uPVC windows are designed and manufactured with multiple air chambers, further enhancing their thermal insulation capabilities. The vast majority of uPVC windows feature three chambers. However, some advanced designs incorporate as many as nine chambers, improving the thermal performance of the windows. Ultimately, the improved thermal performance of the chambers decreases the energy used for heating and cooling.
#2. Superb Insulation Qualities – Aside from the thermal insulation provided by the chambers, uPVC windows achieve low u-values owing to their outstanding insulation properties. uPVC windows have low thermal conductivity. They are less prone to transferring heat from the inside to the outside during winter and from the outside to the inside during winter. As such, thanks to its low thermal conductivity, uPVC is inherently more energy efficient than materials such as metals.
#3. Draft Minimization — Draft through the windows is one of the main ways energy losses occur in traditional windows. When air leaks through the windows, as is common with traditional wooden and metallic windows, it carries away condition air from the indoors to the outdoors, occasioning energy loss.
uPVC windows, on the other hand, are mutinously designed and manufactured to have a perfect seal. The highly efficient seals tend to eradicate the occurrence of drafts, thereby preserving the condition of the air indoors. Importantly, avoiding drafts ensures you do not heat or cool air that will ultimately be lost to the outdoors, thereby saving energy.
#4. Double—And Tripple-Glazing — All uPVC windows are double—or triple-glazed. Windowpane glazing is a mechanism whereby two panes (for double-glazed windows) or three panes (for triple-glazed windows) are joined at the frame while creating a small gas—or air-filled space separating the panes. The small gap is hermetically sealed, ensuring no air gets in or leaves through the windows.
The multiple layers of glass reduce reliance on the air conditioner for heating and cooling, as the small gaps create a thermal barrier to heat transfer. During the warm summer months, the thermal insulation offered by double and tipple glazing reduces the intensity of solar radiation permeating indoors and warming your house. As such, this window system reduces energy consumption for cooling purposes.
Conversely, during winter, the double and triple glazing reduces heat loss through the window, thereby reducing your energy use for heating purposes.
#5. Weatherproof Material — UPVC has superior windows energy efficiency performance than other window materials because of its weatherproof capability. Even when constantly exposed to Mother Nature’s elements, uPVC windows can last longer without cracking. As such, uPVC windows can retain their optimal thermal efficiency and insulation properties for longer.
With the above in mind, it is important to note uPVC, like many other window materials, has a finite life. Over time, the degrading nature of the natural elements will cause wear and tear on the window material. If you notice broken and cracked seals and window frames, you should have the windows replaced immediately, as their energy efficiency performances are compromised.
Aside from being a high-performing, energy-efficient material that is strong, sturdy, and lightweight, uPVC is also recyclable. As such, at the end of its life, the material may be upcycled for use in different ways or recycled to make other uPVC windows. This goes a long way in reducing the environmental impact of creating doors and windows.
