Lo-Cost Solar assisted Home heat

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Seasoned Oak

Minister of Fire
Oct 17, 2008
7,215
Eastern Central PA
AS someone always interested in renewables and solar, i tried a little experiment. Having an opportunity to purchase 6 large(3x8)Ft brand new thermopane windows for $60 each at an overstock auction, I closed in my south facing front porch (24Ft x 6Ft). I also installed a ceramic tile floor with cement board under.
TO my amazement this room would go up to 110Deg and more in the dead of winter even with outside temps around 10-20 Degrees.
However if i open my front door to my living room the area would remain in the 80s as warm air cycled into my home and cool air replaced it.
THe end result was on sunny winter days my home heat(oil at the time) would not kick on all day and well into the night until the sun porch cooled down.
After a years time i was able to conserve a full tank of oil (250Gal) over the winter,at a cost savings of about $$600-$700
In summer the sun is overhead and the porch gets very little sun,so overheating is not a problem.
My next home ill probably build a much larger sun room on the south facing side as we have Lemon,orange and banana trees wintering indoors here in central Pa.
 
It is amazing how much heat the sum makes even on the coldest days. South facing windows and large overhangs are a great setup. Warm in the winter with low sun and the overhang keeps it cool in the summer with high sun. If you had a masonry wall inside that porch, the thermal mass could store some of that heat a little longer. Good old passive solar heating.
 
Nice job! Sounds like that sunroom is performing awsome. I dreamed of doing similar with my porch, but it faces west & is partly shaded. Still gonna try to get the sun heating it in winter though.
One though on
adding thermal mass is that you'd end-up getting less heat in daytime & more at night when you might not need it as much. You could try putting in low & high vents through the wall to get thermal circulation going. then again you could just open the door...
 
midwestcoast said:
Nice job! Sounds like that sunroom is performing awsome. I dreamed of doing similar with my porch, but it faces west & is partly shaded. Still gonna try to get the sun heating it in winter though.
One though on
adding thermal mass is that you'd end-up getting less heat in daytime & more at night when you might not need it as much. You could try putting in low & high vents through the wall to get thermal circulation going. then again you could just open the door...

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THats exactly what i do ,i just open the door and the porch heats my whole first floor to high 70s while the sun porch stays in the low 80s with the cooler air from the house moving along the floor, then a t night i close the steel insulated door and the insulated walls keep the heat in the house till about 10-12 at night. No additional heat needed as long as the sun shines and for about 6-7 hours after it goes down.
 
[quote author="Flatbedford" date="1266014715" If you had a masonry wall inside that porch, the thermal mass could store some of that heat a little longer. Good old passive solar heating."[/quote]

Actually, if you want maximum transfer of heat from a sunspace to living area of the house you want low thermal mass in the sunspace. Any heat that goes into storage in the sun space is heat that doesn't go into the house. After the sun goes down, it's unlikely that the sunspace will stay warm enough long enough to be of much use as far as heating. In the morning, when all that mass is cold, it takes much longer to get the sunspace warm enough to heat the house living space while the mass absorbs the heat. If you're going to store the heat you'd do much better to move it into the house and store it in some mass in the living space.

For some great ideas on sunspaces check out the build it solar web site (actually for anything related to solar, check out this site):

http://www.builditsolar.com/Projects/Sunspace/sunspaces.htm#Guides

There are many other ideas here for solar collectors. Check out the many hot air collectors...fairly cheap and easy to build.

http://www.builditsolar.com/Projects/SpaceHeating/Space_Heating.htm
 
builditsolar is pretty much the best site ever. After hearth.com of course
 
sesmith said:
[quote author="Flatbedford" date="1266014715" If you had a masonry wall inside that porch, the thermal mass could store some of that heat a little longer. Good old passive solar heating."

Actually, if you want maximum transfer of heat from a sunspace to living area of the house you want low thermal mass in the sunspace. Any heat that goes into storage in the sun space is heat that doesn't go into the house. After the sun goes down, it's unlikely that the sunspace will stay warm enough long enough to be of much use as far as heating. In the morning, when all that mass is cold, it takes much longer to get the sunspace warm enough to heat the house living space while the mass absorbs the heat. If you're going to store the heat you'd do much better to move it into the house and store it in some mass in the living space.

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Sesmith
I agree ,thats why my setup works so well .my heat storage is actually the first floor of my home,which wicks the heat all day from the porch thereby not allowing it to overheat. Once the temp of the sunporch drops below the inside temp it(the sunporch) is no longer an asset and i close the door trapping the heat collected all day in my 6 room 1st floor. Very simple ,but it works so well. THe temp of my living room will usually slowly drop from 78 -80 down to 74 where it activates the central heat but by this time its midnight already. SO my FREE HEAT time is from about 10AM to 10-12 PM on sunny days,regardless of outside temps.
 
I was assuming that the masonry would be warming the house and not the porch. I am the son of an architect. I have been hearing about this stuff for nearly 40 years now.
 
trump said:
. SO my FREE HEAT time is from about 10AM to 10-12 PM on sunny days,regardless of outside temps."

Sounds great. I'm using an active hot air collector that I built at my place. As simple as this stuff is, I'm still amazed everytime I have free hot air blowing into my house. If only we had more sun around here :)
 
My house was built almost a hundred years ago with many large windows on the South side and the solar gain on a sunny day even even extreme cold keeps the furnace from running. Some days we',ve even had to leave a door open if there was no in and out traffic.
We had some large water bottles and thermometers for a while , too but they were too big and took up too much valuable space.
 
Flatbedford said:
I was assuming that the masonry would be warming the house and not the porch.

Oh you mean an uninsulated masonry wall btwn porch & house, okay, thought you meant a seperate wall just for therm mass.
I still kinda like a low-mass sunspace for my climate though. With coldish, more cloudy winters & short shoulder seasons, I'd want to seperate the house from the porch & just open it up when conditions are right. In dryer climates with greater daily extremes the more mass the better IMO.
 
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