Solar passive South wall(Now with PIC!!)

Started by w0ace, May 01, 2005, 09:07:32 AM

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So, we have the little house plans, and are planning on a 14x36 with poured concret slab and South wall of glass for some solar passive heating.   I was thinking a 4"x12" built up header over the first 2 units, with 4"x4" pt posts on the sides of the unit, then just normal framing for the rest of the wall, kinda like this....

Corner of the house, 3' for racking, first 6' unit, single 4"x4" post between, next 6' unit, 12' framed wall for laundry room closet and int. hallway, then last 6' unit in bedroom, and 3' to house corner framed for racking.  Numbers don't add up I know, I'll lose 2" off each corner for the 4"x4" post....

So how does this sound???  We want to do stained concret floors, probably black, saw the floor in On the Border Mexican joint here in town having dinner the other night and we liked it ALOT!!  Looked nice and should hold heat great.  Now, if only I could get my 3D cad to work...... ::)  


Sorry for being off-topic, but I'd love to see the floorplan you've come up with for your 14x36. :)


It works pretty well if you have a lot of thermal mass.  Maybe more than "just" a slab floor?  I've certainly lived in houses that got intolerable with solar heating on summer afternoons.  This was due to a couple of things, lack of insulation, lack of thermal mass as well as too many windows in the west, but still.

I know people with slipformed concrete houses, and the one that's been around for 25 years is working well (haven't talked to the other people in a while), but in addition to the mostly concrete construction, north wall buried in the hill, and an absolutely huge masonry fireplace.

They do get to put up awnings (and vines) in the summer to shade all that aggressive solar gain.  It does work pretty well, they cool with a very small AC unit, which they say is mostly for humidity control.

I've had torn retinas, though, so I have a fair amount of trash in my eyes.  Glare bothers me.  So I'm with the authors Christopher Alexander and Christopher Day when they really really want light coming from two directions in each room.

This book, IIRC, reccomends a startlingly low amount of south-facing windows (twenty per cent maybe?), and he wants you to put a layer of concrete blocks going the wrong way (tubes would work!) under the floor slab to move the warm air to the back of the house.


Structurally that should work pretty well. In some earthquake areas your 3' structural wall panel at the corner will need a hold down and a 4x4 at the end to stiffen the panel.

Thermal mass vs glass you might want to consider the ratio. You don't mention your climate and how far north you are but if you have say 75% of your main floor area in open area that could see the sun that would be 250 sf of thermal mass.

From the Sunkit guidelines: ( you could do 12% to 18% of that floor area in south wall glazing. That would be 30-45 sf of window area. A 6' sliding glass door is about 40sf.

If you had the whole main floor open and had three 6' sliders you would have about 24% of the floor area in glass. This is above the suggested amount.

What that would mean in reality is the place would likely overheat in Spring and Fall when you had it closed up and weren't there to vent excess heat. Assuming this is a cold winter climate with decent sun potential, that glass will be appreciated on sunny days. In cold weather you may want insulated interior drapes or panels for night insulation.

In summer you can ventilate and have shades, shutters or exterior blinds.


Thanks John, sounds like it should work then.  We are looking for land in NorthWest AR right now, hoping to find a place with trees that will shade during summer and let the sun on in during the winter.  Best of both worlds then.  That's one reason we have been working on getting the floor plan like we want, so we can find just the right spot for the house to sit on.  


Well, let's try this....

This is just a quick drawing I did so you could kinda get the idea of it.  Let me see if the link worked ok and I'll write a little about what we want to do...


I'll start from the East, or bedroom outer wall and moved to the West thru out the house....

11'x14' bedroom w/3'x8' closet.
Hall way 3'x13'
South side or outer wall of hallway 3'x13 closet for washer/dryer, water heater, pantry.
North side of hall, 5'x8' bathroom, nothing fancy here, just tub across the far north end, then toilet and sink.
On down the hall to the kitchen, looking North from the hall entry way, 2' cabinet, 24" black electric stove, 24" black/stainless dish washer, corner cabinet unit, small single bay stainless kitchen sink, small 10 cu. ft. stainless/black fridge
Dining/living area all open to flow into each other, about 14'x15' total area
Far West or outer hall will be book cases and ent. center built into the wall, floor to ceiling.  
2 6' french doors will be in the dining/living area, the other in the bedroom, they are the broken lines in the top part of the drawing.

Well, that's about it.  Now to just build it.  I have built it a million times in my head so far!! ;)


Hey w0;

The layout of your place is cool (not sure what you mean at the end of the living room where the bookcases are though...?)

I don't think your design makes sense for solar gain etc. if you put all the rooms  on the N side of the house, unless you live in a very warm climate. The way you have it, the bedroom, bath, kitchen and living room are likely to have windows on the N side, but if you flipped it and put those rooms on the S. side they would gain sun, plus you could reduce the number of openings on the N, cold, side and save on heat that way.


This is not a wise crack.....! picked a floor plan that is often used in manufactured homes....very smart use of the space...thery're good designers and use speace very well...seem to always cluster the bath and kit together....not bad!

I'm not to sure about the window locations....if you could add a south facing sun room.....maybe more windows facing southward....

I just ordered the 20 x 30 1 1/2 plan....can't wait!


I have a funny feeling that South is at the top.

Because wOace seems to be really hipped on solar gain.

Or is sitting looking south over the laptop, so that the top really is pointing to the south.

Of course I could never ever done anything like that--never ever be speaking from the voice of experience.  Not hardly. ::)  I'm not using a laptop now!

For daylighting purposes, I'd put a couple of high windows on the W. side (which I am assuming is where the bookcase is).  Light coming in over the washer and dryer might give you glare.

(you could do washer and small freezer, and hope that there wouldn't be more than a day or two without drying on line capability)


OK, so I didn't make this too clear I guess.  The TOP is looking SOUTH.  If you start in the bedroom, the outer wall is on the EAST side.  As you walk thru the house, you are headed WEST.  The rooms won't have any windows other than the south wall, which will be all French doors.  This is the layout we have now in a 3rd. floor condo and we like it.  The French doors let in alot of light.  Sorry for the confusion.  Anyhow, hope it'll work good.  STILL looking for the PERFECT place to build it!! ::)

The West outer wall in the living room will be book cases built floor to ceiling, with the TV and misc. electronics to go with it in the center.  Basically my girl friends own little library.  
73's w0ace