Browse Forums Windows & Doors 1 Jul 09, 2015 9:55 pm Hi guys, I'm building in Sydney south west near Glenfield. Thinking to upgrade the windows or glass doors to double glazing with thermally broken frame. Requirement is : be cool in summer and warm in winter and also saving energy bills. The area is in climate zone 6 or Mild Temperate according to this - http://www.abcb.gov.au/work-program/ene ... -maps.aspx and the suggested window glazing - http://www.wers.net/werscontent/how-to-select-windows Glass type they suggested for Zone 6: Clear Low-E, Clear IGU, Clear IGU Low-E I have been looking at Viridian and Stegbar website for energy efficient glasses and came up with following two options - STEGBAR: http://www.stegbar.com.au/Info-Centre/G ... mance-data VIRIDIAN: http://www.viridianglass.com/products/d ... Energy.pdf Option 1: Glass Type: Viridian ThermoTech double glazing (IGU) with Low E Glass Product : Viridian EnergyTech - EnergyTech Clear Thickness: 4+12(argon)+4 Insulation/Solar: U-Value = 1.5, SHGC = 0.61 Ref : Page 11 of the above Viridian PDF Option 2: Glass Product: STEGBAR/Viridian ComfortPlus Clear 82 Insulation/Solar: U-Value = 3.6, SHGC = 0.68 Thickness: 6.38mm House Plan and orientation: Any suggestions would be appreciated. Thanks in advance. Re: Double glazing or Laminated Low-E glass : Sydney 2Jul 10, 2015 10:11 am You'll want to avoid having Low-E glass to the Northern windows, as this would reduce their heat gain from winter sun. An SHGC of 0.6 means 40% of the heat from the sun is lost. Given these windows are mostly shaded in summer, but not winter, you are better transmitting the radiation. I'd also suggest you get more northern glass into the living, and reduce the western glass onto alfresco. Going back to a 2700 door would give a bit of wall space on the back, and you could open up for more northern window. That outside edge of the 3600 door could get quite a bit of sun in summer mid-afternoon, so the shorter door should work out better thermally. Ideally, the eastern and western windows should be externally shaded from summer sun. You'll want to keep the southern windows comparatively small, which is largely the case. If the pantry is really a pantry through, it shouldn't need much window. There is a niche in Bed 1 that removes the wall insulation. If you are going to the expense of double glazing, I would remove that niche to maintain the insulation in that wall. A window there would perhaps make more sense, as at least you could get winter sun through it. The house is fairly well zoned for summer nighttime cooling, with the bedrooms isolated to the eastern half. To make the best use of this, you could consider putting a door at the end of the passage, so you can condition the bedrooms independently of the living area. If you are using ducted A/C, this may impact the location of return air vents. The choice of glazing is somewhat an economic one, where you trade off the cost of the improved glass units vs the ongoing energy costs. The trade-off point depends on the amount of temperature regulation you are after, and the amount of heating/AC you use. You may be able to base this on your current heating and cooling costs, and estimate how much effect the windows would have. Re: Double glazing or Laminated Low-E glass : Sydney 3Jul 18, 2015 9:24 pm It is clear from the figures that you provide that option 1 glazing is the better option in terms of limiting heat flows. Option 1 provides a window R rating (1/U) of 0.67 compared to an R of 0.28 for option 2. Option 1 has a 2.4 times better thermal performance. The solar heat gain of option 1 is 11% lower. If used on the Northern windows this will decrease passive solar gains in winter. However unlike oneJohn I believe the insulation gains from the low e, which operates 24 hours per day 365 days per year, more than compensates for the lower winter passive gains of the Northern windows. (You could ask for the low e coating to be placed on glass surface 3 for the northern windows - instead of the more normal surface 2 in double glazed units. That will improve the solar heat gain without affecting the thermal resistance.) So Option 1 is preferable to improve the thermal performance though I am sure more expensive. So it is a matter of whether your budget extends to this. Double glazing or Laminated Low-E glass : Sydney 4Aug 08, 2015 9:48 pm Thanks oneJohn & Eccles for your suggestion. I have been thinking a lot about the window configuration and still not sure how should I proceed. Double glazing would give me comfort but it's costly too. I agree with oneJohn about northern windows to be clear glazing for passive heating and using shading during summer time. You asked to increase the window sizes in north. But i have side setback of 900mm and fence will be there. So, I don't get much sunlight by increasing window sizes? The builder said 4-12-4 configuration is not common in residential and only used in commercial building. But I can see from the forum that 12mm argon gap is the best one. Also aluminium sliding window cannot accommodate 4-12-4 size. Builder supplier is stegbar and asked me to look at WERS site - http://werscpd.net.barberry.arvixe.com/table.aspx?Manufacturer=STEGBAR# based on that I have changed window frame from aluminum to composite siteline which is timber inside but aluminium outside. I have come up with following configuration - Building Livingstone23 with Eden Brae Homes This is one of the reasons I decided to go overseas for my double glazed windows. As the builder indicated, he's worked on many upmarket builds, these were the most well… 13 19264 For your reference Performance Labels: Window assemblies in housing, except timber windows, must be labelled so the label can be seen when it is in situ. For timber… 6 7738 4 6201 |