This calculator will help you work out the required Eave depth for ideal Passive Solar benefit for a North facing (Southern hemisphere) or South facing (Northern hemisphere) window.
Remember, the values calculated here should be taken as a rough guide, it does not take into account other effects (like trees, other buildings etc).
Reset & do another calculation.
energy efficiency, sustainable development, passive solar, insulation, buildings
Does altitude affect this calculation? For example I'm in Denver with an altitude of 5280 ft. My latitude is about 39.66. My current home has lots of south facing glass and no roof returns, eaves or other shading devices over its windows. It can overheat in early March all the way through Thanksgiving in late November. On the home I'm going to build should I reduce the "winter shade" value to less than the 21% recommended for 39 degrees latitude. If so how much?
ON Mon, 16 Apr 12, 12:07am probably from United States Reply to this comment
Altitude won't effect it, the angle is relative to the Sun...
ON Tue, 17 Apr 12, 5:04am probably from Australia Reply to this comment
Very suprised by the result. The normal recommended eaves in Victoria are approx 400mm, but we wanted to tweet ours a little to be sure to get optimal passive heating, but shade from November through to end March. Thought we might extend the eaves to 600mm, but calcul;ator tells us over a metre. Seems way to long!
ON Thu, 20 Sep 12, 1:52am probably from Australia Reply to this comment
As stated above: "the eave depth will be deeper than other calculators which only provide part shade during Summer"
ON Thu, 28 Nov 13, 1:49am probably from Australia Reply to this comment
Hi Marg from Victoria Australia, we are building also in Victoria -Wimmera and using eave calculator. What eaves did u finally build to? Our calculator suggested over a metre. Like you, looking to shade for hottest months, Nov to Mar. Our windows face north and are 300 mm off the floor. Ceiling height 2700. Thanking you Ann.
ON Mon, 25 Feb 19, 7:36am probably from Australia Reply to this comment
Obviously the southern facing windows would have greater impact of solar radiation.
ON Wed, 7 Nov 12, 11:31am probably from India Reply to this comment
When you refer to 'summer' in the eave calculator do you mean the astronomically defined summer, i.e. midpoint at the summer solstice? or summer in the sense of the way we think of seasons i.e. June - September in the NH. thank you
ON Mon, 21 Jan 13, 9:14pm probably from France Reply to this comment
Does the pitch of the eave change the calculation?
ON Wed, 26 Jun 13, 7:11am probably from Australia Reply to this comment
Im a little confused with this calculator, the height from the ground seems minimal, my wall heights is going to be 2.9. When i put in the height from bottom of window to eaves, surely there needs to be a box for total wall height?
ON Sun, 25 Jan 15, 4:15am probably from Australia Reply to this comment
Hi, i am designing an alucobond fascia/eave set up. The house is north facing and has full height window below. Will reducing the eave by 100mm make a big difference to the overall energy rating. I am in south Australia.
ON Sun, 3 Jul 16, 1:17am probably from Australia Reply to this comment
Gosh, after looking at tons of passive solar home design books (and writing one--I was wanting to give an easy online tool to people for their use) and searching online forever, I finally found your EASY tool here. THANKS! So glad to see something so simple to use compared to other sites.
ON Sun, 7 Jan 18, 11:19pm probably from Canada Reply to this comment
Many thanks for this. Saved me a bit of time designing my new home. I particularly like the automatic look-ups
ON Mon, 29 Apr 19, 10:24am probably from Australia Reply to this comment
Um, what Peta said! I want to calculate overhang for my dormer windows, where the bottom of the glazing is approx 3m from the ground. Rather disappointed that you have not fixed this issue in 5 years...
ON Sat, 22 Aug 20, 10:55am probably from United Kingdom Reply to this comment
I used the eave depth calculator but never seem to be able ro see where the answer is and the calc form returns to Afghanistan. What am I doing wrong?
ON Mon, 14 Dec 20, 7:53pm probably from United States Reply to this comment
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