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Passive Solar House gain at the Winter Solstice Also Summer Solstice

JUGHNE Member Posts: 11,021
edited October 2021 in THE MAIN WALL
In the early 90's we started our house. We tried to align it on the north-south axis for max solar gain.
The sun room shows the max penetration of sunlight on Dec 22, solstice this year.
We are in the CST zone about 80 miles from MST. So true noon is 12:35.



  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    Pretty nice, looks spot on.

    If I hold up a stick with a jewel on it, will it show me where the treasure is located?
    Near me at Longwood Gardens, they have a solar calendar, marked on the ground. Always found it interesting.
    And of course what the Mayan's accomplished.
    JUGHNE Member Posts: 11,021
    Thanks Steve......send me that precious jewel and I'll look for it....but the solstice has passed for this year.

    That is 16' of sun into a 20' deep room.
    On summer solstice no sun enters the windows.
    Very simple to figure out on graph paper.
    House looks "normal" inside and out.
  • hot_rod
    hot_rod Member Posts: 21,868
    radiant floor heat? Why the portable electric heater :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    JUGHNE Member Posts: 11,021
    That is a cooling fan I knew I should have removed before shooting.....some relatives get overheated in this room....they live with heat pumps and require the annoyance of moving air.

    Almost 900' of 1/2" tubing on 6" centers. Temp set at 73, wife and I like it barefoot comfy, but overshoots with 15 people and good sun. I am constantly closing windows and doors when they are here. Always a discussion at holidays.

    Come July 4th AC switched off when they all leave. They all work in over cooled buildings. ;)
  • Jim100Flower
    Jim100Flower Member Posts: 102
    Looks like a perfect alignment!
    My house was also designed for passive solar heating and an overhanging balcony/walkway blocks the sun when the summer sun is high in the sky.
    The solstice was cloudy but here is a capture from my smart thermostat app showing a 9F indoor temperature rise due to solar heating on one of the darkest days of the year. I love not running the heat in the winter!

  • retiredguy
    retiredguy Member Posts: 885
    I like the massage table. MY wife has the same table and I really enjoy it when she feels like offering me a full body massage.
  • ethicalpaul
    ethicalpaul Member Posts: 5,615
    Is it better to avoid UV blocking glass when thinking along these lines, or does that not affect the heat gain?
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    JUGHNE Member Posts: 11,021
    The glass is Andersen "High performance" insulating glass of the early 90's.
    Winter U-value of .32
    The claim is that it passes direct sunlight to produce radiant heat in your house but will not redirect radiant to the outside and then will not allow much radiant from the outside summer sun to be bounced into your house.....even if the glass is shaded from the sun the radiant from pavement/sidewalks are directed into your glass. The Hi-per glass was supposed to not allow reflected radiant to go in or out.
    The glass is supposed to reduce UV by 71%.

    The massage table is my wife's, as she was in the business.
    We get a almost weekly house call for both of us from the massage girl. How about that? Some bennies of a small town.
    It is to her advantage as we supply the linens, a bit of an expense she can avoid.
  • nibs
    nibs Member Posts: 503
    Very nicely done and thanks for showing it to us.

  • nibs
    nibs Member Posts: 503
    The morning we left for an Xmas visit with the grandkids, turned down the radiant slab boiler thermostat, from 70 to 50 F, boiler did not light up for six days, with outside temps 20 to 30 F. House is still not completely insulated. Must be getting solar gain.
    JUGHNE Member Posts: 11,021
    Thank you.
    Yes max solar gain in winter but minimal heat gain in the summer.

    Also, the advantage of cross ventilation in the cooling season.
    The north room windows/doors will flow air thru the entire house in either direction.

    This was taken June 21, summer Solstice. All the first floor glass is shaded by the over hang.

    The over hang is 30". The soffit and inside ceiling are at the same elevation height wise.
    What you see different on the outside is about the same 12" of wall above the windows as you see inside.

    The roof trusses were designed and built on site to accommodate the soffit elevation.
    This also would be considered an "energy truss" as it allows for at least 12" of attic insulation right above the outside walls.

    There are only 2 west windows and one east window to cut down on solar gain in the summer.

    It has to be a couple of days of near 90 degrees to have to run the AC.
    Night time breeze cools house for the next day.

    But this is on a 2 acre lot. So we get full south wind in the summertime. And trees on the north block the winter winds.

    You can see it is the drought time of the year. With a good rain the grass greens up nicely.

  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,214
    Nice to see someone taking advantage of simple, solid site planning with solar. What you have there is exactly what we learned at IIT in the Architecture program. Typically the passive solar savings in the winter used to calculated at around 30% in Chicago.....Its probably much higher with well insulated structures. When I built my garage for my last home it was 24ft north/south and 34 feet east/ west, 2x6 insulated wall and ceilings with drywall. I put in 3 large 4ft x 6 ft standand fixed thermopane windows. With no supplementary heating, a milk jug of water in on the floor never even became slushy in the 3 winters we were there. The drywall still needed to be taped on some of the walls and ceiling still. I imagine your home cost nothing more than a typical home...just good design.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Jamie Hall
    Jamie Hall Member Posts: 22,934
    Nice. Very nice. But if I may say so... goes a long way to proving what I've been muttering for the last 40 years or so. Passive solar heated houses work, and work in some pretty miserable climates -- and they don't have to have any fancy tricks or look weird. Just good design.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    JUGHNE Member Posts: 11,021
    We got the ideas from the early work of others done in the 70's.
    Even "The Mother Earth News", but one of the handiest most comprehensive books was "The Passive Solar Energy Book" by Edward Mazria. Published by Rodale Press 1979. 686 pages.

    We also looked at some Canadaian wall designs and methods of preventing air infiltration.
    We ended up with 2 x 6 wall with FG, covered by super poly vapour barrier...(Hey, it was Canadian info and they speak the Queen's English there....or French)
    Then that covered with 1" Styrofoam insulation covered with 5/8" SR.
    The belief is that if your vapor (vapour) barrier is behind only 1/3 of your R value (on the warm wall side) and the other 2/3 is cold wall that no condensing of water vapor will occur.
    The poly starts in the basement lying on the sill plate, around the rim joist, coming into the house, then up the walls, across the ceiling and back down the opposite exterior wall around the rim joist/sill and hanging into the basement. The rim joist is set 2" into/towards the interior and that 2" is insulated with styrofoam also.

    Just about no electrical penetrations in the exterior walls. Where outlets were absolutely necessary then a cable come up thru the floor with surface mounted wiremold. Recessed wall switches where needed on exterior walls are wrapped with the poly and all holes sealed. Wall sconces were used for most of the lighting.
    Any ceiling boxes were polyed/sealed.
    No recessed lights in insulated ceiling. Several track lights with limited ceiling penetrations.

    The entire house was SR'ed with 5/8", all exterior walls and ceiling SR before any interior walls installed.
    SR is an addition vapor barrier. The 5/8" adds mass to the house. Of course backing on 2' centers had to be installed for inside walls before SR. 6" screws were required to secure the inside walls to the buried backers.

    DWV was all in interior walls. Water supplies in inside walls or up thru floor.

    All exhaust fans; 4 baths, range and dryer vented down thru wall into basement and then out thru rim joists. 2 bath exhaust fans are in soffit above WC with adjoining 2 x 6 inside wall to handle 4" round pipe going down. 1/2 bath has wall installed fan with 3": round pipe inside wall going down. Basement bath fan goes straight out the rim joist. Range hood has wall stack going down to 6" round to daylight.

    Exhaust fans are on motion detectors or timers.

    Tub/shower enclosures, if on outside wall had the cold wall side completely SR'ed. So allowances had to be made for that dimension change.

    The basement walls are a "sandwich" of 4" concrete--3" beadboard foam--and 5" concrete inside.
    12" total with brick form inside and smooth outside for stucco.
    Those walls are very labor intensive and difficult to find someone to do that. It involves pouring one side, then pulling the forms, insulating and resetting the forms for the next form. 16" long form ties.
    Rebar every 2' both directions for both wall pours.

    As I type all this I realize how labor intensive this project was. Yes, it looks like a "normal" house, but there is a lot of things buried inside the walls that no one sees.
    We had a very understanding general contractor for the major framing. Then an independent guy for inside work who would roll his eyes occasionally as the plans were laid out for all the oddities.

    Then how could you walk an electrician and plumber thru this??
    How could they bid this if necessary?
    Of course I did all the electrical, plumbing, HVAC, painting, the front pavers and ceramic tile myself with the help of some teenagers (kicking & screaming involved--but they now do all this themselves in their own houses).
    It took about 3-4 years to get it finished enough to move into.

    Just describing the work done tires me out and I feel older than I was 25 years ago.
  • hot_rod
    hot_rod Member Posts: 21,868
    Nice to hear about your home, especially the track record of comfort
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • JakeCK
    JakeCK Member Posts: 1,356
    edited October 2021
    How do you handle air exchange? HRV or ERV I'm guessing? A house that tight would have to have all air exchange mechanically performed.

    One other thought about your exhaust fans. You mentioned motion or timers for control. How about humidistat control for the bathrooms? Of course we use our fans for when we're on the 'throne' but the larger concern is control of humidity, especially in the summer. The time it takes for the humidity to be brought down after one of the wife's 20+ minute steam showers varies greatly and is much longer then one would think to set a timer for.
  • JakeCK
    JakeCK Member Posts: 1,356
    edited October 2021
    And contractors rolling their eyes when getting paid to perform a service to a HO's specs is one thing that really burns my ****.