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Posted by john sullivan on November 27, 2004, 8:21 pm
Hi, I've just started reading the group to research a project I was
considering, and was hoping someone here would be able to offer me
some advice.  I certainly haven't seen much solar activity here in San
Francisco.  I spoke to some solar providers at the Green Festival last
month and none seem to have had more than a dozen jobs here,
apparently due to the fog and/or the roof shapes/orientation?

Anyway, I've noticed many days where solar heating would work great
(warm south-facing front, cold back) and wanted to try and store the
sun's heat to warm the rest of the house.

The house was built in 1890 and is a stick victorian, three stories
tall, about 3500 sq ft, lots of 8 ft tall windows, hardwood floors,
currently with two furnaces.  The roof is flat and gets full sun (25
ft by 75 ft).  The floors are connected via stairs, and the bottom has
the garage and more living space (about 600 sq ft).

The project I'm considering involves replacing the existing foundation
anyway, along with most of the poured cement due to it's age and
condition.  I'd like to put a radiant floor in the bottom floor (even
in the garage) and at the same time, with the bottom ceiling being
redone anyway, run the water tubes underneath the floor of the first
level.  I have plenty of space for a big storage tank in the back yard
or garage.  I'm thinking the top level probably wouldn't need much
heating and can use the existing furnace if it was needed.  I wanted
to use solar as primary with a high-efficiency gas water heater as the
backup for the radiant flooring.

The bottom floor would then be a radiant cement slab of about 1500 sq
ft, along with the radiant tubing running under about another 1500 sq
ft of wood flooring on the first floor.

Any pointers, even hypothetical ones, on such a project would be

Posted by nicksanspam on November 30, 2004, 2:37 pm

How would you collect the heat?

Sounds like it has lots of air leaks and little insulation. And it's
probably "cute," so you won't want to modify the facade. You might
gut the inside, insulate, airseal, and make an internal sunspace...

...75' EW? January's the worst-case month for solar house heating in SF,
when 1050 Btu/ft^2 falls on a south wall on an average 48.7 F day with
a 55.6 average daily max.

Solar heating can work fine in SF, but this sounds like trying to bail
a bottomless boat. You might sell the house and start from scratch, or
build a solar penthouse from scratch and live up there.


Posted by john sullivan on December 1, 2004, 5:30 am
 nicksanspam@ece.villanova.edu wrote in message

Thanks for responding.

I was thinking of using solar panels, either the flat panel or
evacuated tubes, but this is the least of my issues at this point!
Finding an architect and engineer that knows something of the area
seems primary.

The ceiling is insulated and the leaks have been addressed.  The
windows are just really big, and I was hoping to get some info on the
percentage difference between the single-pane windows and good
double-pane to see whether I should replace them all.  The walls butt
against the houses against me.  I already have plenty of sun in the
front of the house and a sky light.

NS.  The front faces south.   In SF, the stick victorians are built
narrow and long.  The coldest month "seems" to be June, when the fog
comes in over most of the city.  January is cold but sunny.

Hope not.  Thanks for the input, maybe I'll try over at
alt.architecture to see if anyone has actually seen such a project

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