I actually agree with the opinion of your architect. Although Low-E windows, especially Selective Low-E for cooling climates, are a lot more energy efficient than regular uncoated glazing, their energy efficiency is difficult to match that of a well-insulated wall. The savings from daylighting max out at around 20% Window-to-Wall Ratio, and anything beyond there you would be fighting both the conduction as well as unneeded solar radiation through the windows as compared to an opaque wall.
Joe
Joe Huang White Box Technologies, Inc. 346 Rheem Blvd., Suite 205A Moraga CA 94556 yjhuang@xxxxxxxxxxxxxxxxxxxxxxxx http://weather.whiteboxtechnologies.com for simulation-ready weather data (o) (925)388-0265 (c) (510)928-2683 "building energy simulations at your fingertips"
Dear Mr. Ali,There are two factors (at least) in play regarding the glass for your villa. One is energy use and the other is aesthetics - both are important.
I can speak to the energy factor in this way:Energy use in a specific location and for a specific design and purpose is not something which can be fully evaluated with rules of thumb or even research papers; there are too many factors to condense into a simple rule or result. You have posted this question on an energy modeling forum, however - a very good choice.I recommend that you engage a good energy modeler to prepare an energy model which incorporates all of the key factors for your villa design, and see which glazing option works best for you.
p.s., Other general factors which you might consider include visual glare and privacy. Other glazing options include shading devices and thermochromic or electrochromic glass.
On Sun, May 28, 2017 at 4:41 PM, Mohammed AlZain <energizeralzain2000@xxxxxxxxx> wrote:
DearI am in the designing stage of my villa (located in JEDDAH, SA: 21.2854° N, 39.2376° E). I expressed my desire to the architect that 60-70% of the facade of the villa to be LOW-E glass in order to enjoy 100% natural lighting during the day and to conserve on my cooling bill at the same time. I was surprised when he said that the well-insulated concrete or brick wall is much energy efficient than even double-glazed or triple-glazed low-e glass. He added that the amount of savings due to natural lighting is off-set by the deference in energy conservation efficiency between double-glazed or triple-glazed low-e glass and the well-insulated concrete or brick wall. Especially in this location. I was puzzled, because I had a strong belief that LOW-E glass is the best option for energy efficiency enthusiast. If somebody has a professional opinion please share it with me.I also would like to share your opinion on my emails:BRMohammed Ali
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