Let there be light! « Alternative Technology Assn Forums

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Let there be light!

(10 posts) (6 voices)

Started 3 years ago by Dexter
Latest reply from Morbo

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Dexter
Member

Hi all - I have not posted for quite some time and have delayed my build be equal measure! I am finally at the stage of perhaps maybe taking concept plans to council shortly and am after some help with light analysis.
Our house is facing 30 degrees East of North (in Adelaide); our walls will be 3 metres in height and windows 2.4 metres in height; I want as much natural light as possible whilst still blocking out summer heat. I have decided on a wide veranda eve of 1.8 metres. This does block out the majority of summer direct light and allow a decent amount of winter direct light (around 50% shaded by 2pm). I am concerned however once the sun passes over at any time of year with such a wide eve it is going to be dingy looking inside!
I am considering instead having a 0.6 metre eve with a 1.2 metre louvre to take control of light! I think even when there is no direct light on the windows opening up the louvres will allow some diffuse light in to brighten up the room!
Not being made of money though I don't want to go to the expense of louvres if there is not going to be much benefit!
Your expertise and or opinions would be greatly appreciated.

Dexter

Posted Wednesday 1 Nov 2017 @ 1:16:01 pm from IP #
arttt
Member

Why not align the house much closer to north?
How dingy it is depends on lots of things like how much glass there is, how deep the room is, how low the wide eve is, colours used etc etc.
If you post some plans im sure you will get all sorts of great feedback.
If you want to get a feel sunlight penetration throughout the year it is worth doing a quick 3d plan in sketchup.

Posted Wednesday 1 Nov 2017 @ 10:41:11 pm from IP #
Dexter
Member

Hi arttt - I would love to align the house closer to north but the land wont allow it! we are on a slope and have designed a long skinny house to have as much facing towards the north as possible - turning the house any further will look very wrong for our block and would also put one end of the house too close to a large gum! Hopefully I can upload a snippit of the plans tomorrow - the main room is aprox 10 by 7 metres accommodating the kitchen dining and living area - the north facing wall Is mostly glass with 2 large windows and 1 large sliding door so maybe there will be enough light, just worried the depth of the veranda will waste having all the glass!
Have never used sketchup - just watched a couple of tuturials - they make it "look" easy ?! :O)

Posted Thursday 2 Nov 2017 @ 11:42:21 am from IP #
arttt
Member

You can keep the model in sketchup very basic if you are only using it to explore sun angles. Just a box of the right dimensions and orientation with holes for windows and more boxes for any shading structure like eaves, trees, other buildings etc.

Posted Friday 3 Nov 2017 @ 1:12:12 am from IP #
dave lawrence
Member

with a 1.8 m north facing verandah, you will effectively destroy any solar passive gains, UNLESS your verandah beam height is minimum 3.6 m.
This is a generalisation ,BUT is almost certainly accurate.
There are some options available to counteract the loss of these potential heat gains ,BUT without seeing cross sections or elevations impossible for me to comment further .

Posted Friday 3 Nov 2017 @ 2:49:49 am from IP #
dave lawrence
Member

north facing verandahs ARE not generally compatible with solar passive design IF typical roof designs are used. THEY CAN work really well if you use the right roof design HENCE my previous comment about seeing cross sections and elevations .Although floor plan layouts are the starting point for solar passive designs ,they must be designed in tandem with the roof design if they are to function to their maximum potential .

Posted Friday 3 Nov 2017 @ 2:53:43 am from IP #
Francis
Member

Have you considered a light shelf (bounce light up to ceiling) with external horizontal awnings placed between your north facing windows vertically? This would reduce depth required by your eaves for shading.

For example, a clerestory 300mm window, 100mm wall/light shelf, 2100mm window from floor up.

Posted Friday 3 Nov 2017 @ 3:57:38 am from IP #
Johnnojack
Member

For a full height (to floor) window facing North I have found that the 600mm eave is fine in Dec January and most of February. After that the sun comes in which is definitely a problem because the weather is still hot and can be very hot. To address this I have a frame extending out where I can place effectively an extension on the eaves to make them 1400mm. This keeps out the sun for the those later months. It is enlightening however (pun intended) to take down the extension by the end of April approx to let the light back in. So yes I'd recommend louvers or similar. Your 1800mm sounds about right as you will need more width when angled away from North.

Posted Friday 3 Nov 2017 @ 9:24:09 am from IP #
Dexter
Member

Hi all - Our original design (well actually about 15 plans in) had 3.6 metre frontage with clerestory windows. We are building in a hills facing zone and it is very unlikely this would get approved by council - anything over 3 metre wall height (5 metre gable ends) does not pass the guidelines for hills facing. There is also nothing like this in the area so the house would stick out like a sore thumb; another cross as far as the council is concerned. Hence we have changed the plans to have 3 metre walls and a veranda, pitch roof with gable ends. I quite like the look, heading away from the modern!

Did a little hi-tech experiment yesterday morning - some of our bedrooms in our existing house face pretty close to 30 degrees east of north - I stood outside with an umbrella held up at a 3 metre height and aprox 1.8 metres from the house, yes I said hi-tech - the results were not promising - no sun hit the window and the room darkened significantly - this is the pretty obvious result I guess but was good to see it with my own eyes! Looks like if I want light louvres will be the go!!!

ummmm, forum dummy here - how do you attach stuff - have some snippits of the house plans to share!

Posted Sunday 5 Nov 2017 @ 1:35:41 am from IP #
Morbo
Member

http://www.ata.org.au/forums/topic/46654#post-98113

find image hoster such as imgur, copy image link. See post 4 of linked post. Click on quote and you see, how its done

Posted Sunday 5 Nov 2017 @ 6:37:57 am from IP #

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