> Passive Solar Eaves Calculator
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.
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Comments left
- Bill said:
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
- Eco Guy said:
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
- Eco Guy said:
- Marg said:
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
- Rob said:
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
- Ann said:
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
- Rob said:
- David Warner said:
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
- Caveman said:
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
- Shalyn said:
Does the pitch of the eave change the calculation?
ON Wed, 26 Jun 13, 7:11am probably from Australia Reply to this comment
- Peta said:
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
- David Timms said:
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
- Sharon Buydens said:
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
- Jonathan Sturm said:
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
- Sarah Mould said:
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
- lonnydk said:
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
- Ken Furber said:
You might want to check your overhang calculator because I think it may be a bit off. I actually just designed a passive solar earth bermed hillside house to be built here in Southern California and your calculator would have me using an overhang that is a whopping 40% deeper than what I actually ended up using. Los Angeles is at approximately 34 degrees of latitude (pretty close to the southerly latitude of Sydney) and when you subtract the earth’s tilt you find that in summertime the sun is only about ten degrees away from being directly overhead – not much overhang needed there. And with this information alone I could pretty accurately ballpark what the overhang should be in my head. By the way, I ultimately decided on the correct overhang by putting my latitude into the architecture design software and actually seeing on the 3D renderings how much direct sunlight came in through the windows at a given time of the year with a given overhang. Anyway, although I trust my calculations there is nothing like actually seeing the results of those calculations in a simulation with your own two eyes. Modern technology is really amazing. When I was studying architecture back in the 70’s we had to draw everything on paper and then put the finished plans through a blueprint machine. But with today’s CAD programs you can see photo realistic 3-D renderings of your house at the touch of a button. Back to passive solar designs though, calculating the proper percentage of thermal mass to south facing window area is actually more important than getting the overhang exactly perfect.
ON Tue, 14 Nov 23, 2:37am probably from United States Reply to this comment
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