With heating and cooling accounting for 40% of the average Australian household's energy bill, many are turning to double glazing as a way to cut down on energy bills. If you're wondering about whether or not to double glaze your windows, learn how glazing can affect energy use in several different ways.
The Basics
Your home gains or loses heat in three ways: convection, conduction, and radiation. Heat can enter or escape the home with air, through unsealed cracks or open doors. This type of heat transfer is called convection. When heat transfers through a surface—like the glass of a window—the transfer is conduction. Lastly, hot objects also give off heat in the form of infrared radiation.
The goal of an energy-efficient window system is to reduce all three types of heat transfer. The flow of heat through a window from all three sources is measured by the window's U-value. The lower the value, the more energy-efficient the window.
U-value and you
A low U-value window, such as a double-glazed window, retains heat better in winter and keeps it out better in summer. You may have heard that north-facing windows should be single-glazed in order to heat the home passively during the winter. In fact, the loss of heat through this type of window cancels out any advantage from more rapid heating.
The ideal combination for this type of window is double-glazing with a low-emissivity or low e-coating. This coating acts as a mirror for heat, preventing it from passing out through the glass. Combined with other types of coating, this can create either a window that blocks out the sun's heat or one that allows it in but reduces the amount that escapes.
Solar heat gain
However, U-value isn't the only factor that influences home energy efficiency. In Melbourne or other areas with cool climates, heat retention in winter really matters. In Darwin or Brisbane, the story is different. In these hotter environments, a window's solar heat gain coefficient, or SHGC, is what matters.
A low SHGC means that a window reflects most of the sun's heat. The amount of sunlight reflected depends on the angle at which the sun's rays strike the window, meaning that most windows let in more solar heat when the sun is lower in the sky.
A low U-value may always be good, but a home's SHGC needs can vary. In hot climates, a low SHGC is desirable; in a cooler climate, different parts of the house may require windows with different coefficients. For a second opinion of what you need for your home, you can contact companies like Enviro Vision UPVC.
Share15 June 2015
The kitchen is the most used room in my home, and in the past, I found it could get messy and chaotic very quickly. Trying to cook dinner when you can't find an essential appliance or see past the clutter on the counter is no fun. I realised I enjoyed my time in the kitchen more and was more productive when my kitchen was organised and laid out in a way that optimised functionality. I changed my kitchen cleaning and organising routine, decluttered, got rid of appliances I don't use and moved things around to ensure frequently used items were easy to reach. I started this blog to share my tips for creating a kitchen that's enjoyable to use, and I post about ways you can optimise the space you have. I hope you find my posts useful.
