Hi all. I havent posted much in the forum before, but have come to the start of building my new home and wanted some advice on my eaves specifically. My architect was not terribly knowledgable on passive solar design or much sustainable design, but i am trying to get my house as efficient as possible. I am finding very hard to get the eaves design right and would happily pay someone to look at my plans. I need to get the shading correct and am not confident in my own research as the house rear faces NE/NW. So i have 2 sets of windows that need shading that is not as simple as the normal online tools that i have found. Would be grateful for any help, links, companies etc that can assist me before my builder orders the roof trusses etc. I am considering external blinds also, but want to get the basics right before spending money on the fancy stuff.
Thanks in advance!!
Passive Solar Advice
(6 posts) (5 voices)-
Posted Monday 20 Feb 2017 @ 4:49:21 am from IP #
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Search this forum, there may be some links to good tools. It's just trigonometry, no need to pay anyone. Sun makes angle of 75 degrees ish from horizontal in summer and 30 degrees in winter, 43 at the start of autumn and 60 start of spring. You want to size the eaves to it blocks most of the summer sun and some of the spring/autumn sun.
Would be good to know your ceiling height, window heights and location.
Posted Monday 20 Feb 2017 @ 6:28:01 am from IP # -
Thanks dlvb19. As i understand it though, those angles are for due North. There must be some calcs that will allow for the direction that the window faces. (mine are NW and NE)
Posted Monday 20 Feb 2017 @ 7:00:49 am from IP # -
The size of the eaves aren't the problem with your windows direction.
Standard solar eaves will provide protection against the sun for the hours around midday.The issue is really late afternoon/evening when the sun is low in the sky. that can only be addressed with either some sort of shading on the side of the window or in front of the between the late afternoon sun and the window such as a tree, or shade sail.
Posted Monday 20 Feb 2017 @ 10:02:44 pm from IP # -
As bashworth implies the "standard" method of calculating eave width will not apply in your situation as your windows don't face north. There's no fixed angle of the sun to work with so a fixed eave will not work to shade your windows all day. Early in the morning the sun will be in the E and very low and will shine under any sized eave you have on your NE windows. All you can do is decide between what times you will want shade from the eave (say 9am to 3pm), work out what the sun angle is at those times and hence what eave size you need. Your architect should be aware of software that can model this for you - I think there's even free software as part of windows that can do this including solar shading.
Posted Monday 20 Feb 2017 @ 11:51:16 pm from IP # -
Bought a house about 45 years ago which faced Nth East. In summer the sun came in every window on all four sides, sun even came past the many canvas blinds because of the angle. 7 years later built a house elsewhere which did face Nth ( but did not quite face the street) neighbours thought I was mad. I had the last laugh though with the only ' warm/cool' house in the court.
Posted Tuesday 21 Feb 2017 @ 7:48:17 am from IP #