South or southeast orientation in Southwest U.S.?
I will be building a 20×40 rectangular house on a slab on grade with a painted concrete floor. It will have a gable roof and 2′ overhangs all around and minimal windows on all but the south side. It will be located in Arizona, in the slightly cooler part of Climate Zone 2B, where typical winter days range from 28 at night to 55 in the afternoon and summer days range from 60 at night to 100 in the afternoon Is the ideal orientation for the long side of the house to face due south, or should it face somewhat southeast so that it warms faster in the morning sun and catches less sun in the afternoon? If the latter, how would the ideal southeast angle be determined?
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Jeff,
I vote for due south. It simplifies overhang design.
I doubt whether the purported advantages of wintertime solar heat gain through east-facing windows outweigh the clear disadvantages of summertime heat gain through those same windows. I would minimize the size of east-facing windows if I were you.
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Porch on the west side for west side window shading. Bedroom on the east side wake to sunshine. Bathrooms on the northside, dining room shaded by the west porch. Insulate the ceiling well, use foil backed plywood for the roof sheathing.
Another vote for due south, with the roof lines optimized for photovoltaic solar. Even if it's not cost-effective to install the solar now, it will be well before the shingles are toast (and it might be cost effective now, with or without subsidy incentives and tax credits- it depends upon your utility rates.) By 2025 the lifecycle cost of rooftop solar power will be cheaper than the residential retail rates almost everywhere in the US, and may be below the wholesale grid rate for large parts of the US. With any new construction it's useful to keep this in mind, and not design, shade or site-orient yourself out of being able to take advantage of cheap PV.
马丁正是最小化的东西面向玻璃。事实证明，东面的窗户是我几年前在气候区5A中参与的一个高R房屋项目的唯一舒适问题，在阳光明媚的7月早晨将乘员从东侧卧室里烤出来。（甚至没有那么多的窗户区域！）如果您有任何重要的东西方面或西面向玻璃，您可能需要外部阴影来杀死不必要的季节性收益，因为它需要一个深层的门廊才能用悬垂的悬垂物来减少它。正如AJ所建议的。
Thank you. The house will have just two very small windows on the east and west sides. The difference between facing due south and somewhat southeast will be felt in how much sun the bigger south-facing windows get in the cooler morning versus the hotter afternoon.
根据Susdesign.com非常方便的工具，如果房屋面对南部，我的2'悬垂物在一天中的任何时间在1/22、11/22和12/22的任何时间都不会遮挡更大的窗户。它将在2/22和10/22的25％和10/22，在3/22和9/22上蒙上阴影，4月至8月100％。三月在这里不是热，但是九月是。