On 09-28-97 Bob Stauffer wrote to All... 
 
 BS> Is any one familiar with the advantages or disadvantages of ground 
 BS> source heating?... 
My home burned last year, but lemmee suggest some points. South 
facing slope, dug into the hillside, bermed with the excavation 
on the north side. I had a 20X36 with a 12X14 greenhouse on the 
south side with the floor contiguous with the cellar, and open 
wall into it.  north arkansas, 36o N.  winter lows 5-10 below. 
 
despite not being heated, the greenhouse got enough air from the 
cellar that plants did not freeze.  But during the winter, the 
day length is so short that growth is trivial until feb.  Greens 
would start well in it, but tenders still needed warmer air to 
do anything, but were small enough to do on the main floor window 
sills till the weather moderated in march for transfer to the  
green house. 
 
Ground temp at this latitude is 58o F.  I had vents in the top 
of the greenhouse that fed into the kitchen; the top of the 
greenhouse glass was just below counter top level, so normal 
kitchen windows could be used in the south wall above it. by 
FEB afternoon air in the mid 80's came into the kitchen from 
the vents at the back of the counters along the south wall. 
 
During the summer, the greenhouse was emptied, and covered with 
foam insulation alum/reflecting panels.  Deciduous trees shaded 
it too, helping a lot. now, the extra floor space in the green 
house added to cellar floor totaled 900 square feet at 58o, and 
the trick was to get that air upstairs.  Since the joint ran on 
PV panels, I only used a computer blower to feed one room, the 
rest of the house... well there was a skylight that opened in the 
roof, and the hot upstairs air exited- to be replaced by the air 
that came up thru the pantry from the cellar stairway... if all 
the other doors and windows were closed... oh yeah. cellar door 
on the north side to let air in. 
 
There is a considerable micro climate effect in forested hilly 
land like this.  Little Rock July 4 pm temp 98o.  Clinton, a 
small town 30 miles east, at 93o.  Post office at country store 
at Tilly, on a ridge between Archie & Bear Creek- 88o.  Back on 
the mountain, away from the cleared pasture land, 86o.  On a  SE 
facing forested slope, the sun no longer penetrates to the floor 
of the forest, so the air next to the ground begins to cool off, 
and slide downhill- 83o by the time it looses 200 foot of elev. 
 
If outta dumb luck or foresight, you put your place in a wash on 
the side of such a slope, you find a 3-4 mile breeze start up as 
this air begins to *funnel* down the hill every afternoon at 4pm. 
By 5 pm the temp is 79o, and it is still 98 in Little Rock.  By 
the next mourning, it is between 57 and 62, while the overnight 
low in the city is 78-82.  Bear in mind, this has some effect in 
the rest of the year. 
 
However, when the leaves fall, the east slope warms up quick in 
the mourning, and as cool air sinks, the frost will be late in 
spring and early in fall, by 3 weeks or so.  From the standpoint 
of heating it is not so bad, as the effect is easily blown away 
by any winter wind; in this case an east or se facing slope will 
be outta the teeth of a NW Yukon clipper. 
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