# how many sq ft of panel needed?

Posted by greif on November 4, 2007, 12:26 am

hi

how many sq ft of flat panel needed to heat house with hot water?
house is located just south of green bay, wi. house is 3000 sq ft of
main floor and 3000 in basement with has radint heat in the conrete
floor. 2 year old house with spray foam insulation.

are there any calculator programs/ web sites out there?

thanks

Posted by Morris Dovey on November 4, 2007, 8:30 am

greif wrote:

| how many sq ft of flat panel needed to heat house with hot water?
| house is located just south of green bay, wi. house is 3000 sq ft of
| main floor and 3000 in basement with has radint heat in the conrete
| floor. 2 year old house with spray foam insulation.
|
| are there any calculator programs/ web sites out there?

I'm fairly sure that a web search should turn up a few. You still have
a few unspecified variables (orientation of panels, expected
efficiency, etc).

that'll let you play with the parameters for vertical panel(s).

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/

Posted by greif on November 4, 2007, 6:42 pm
in winter.

expected efficiency, don't have a clue

thanks

Posted by Morris Dovey on November 4, 2007, 7:10 pm
greif wrote:

| sun in winter.

This will depend on where you put the panels. If they're aimed
directly at the sun, you get one 'sunpower' - but if the panels are
mounted vertically where they can pick up snow-reflected light, you
can get as much as 1.9 'sunpower'. It's worth a bit of thought...

| expected efficiency, don't have a clue

If you are choosing between panel A and panel B, and panel A is twice
as efficient as panel B, then you will only need half as many of panel
A as you would of panel B to do the same job.

It might be worth investigating. Cluefulness is often rewarded. :-)

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/

Posted by Sundug on November 4, 2007, 1:01 pm

I`ve read to use 20sq' for the first occupant, and 10sq' for each
additional occupant. This assumes proper orientation and solar
exposure. However, I have 40 sq' for the two of us and it works out
well. Doug

DIY Solar Hot Water Articles can be found here:

http://www.solarfacts.net/articles/diy/diy_solar_hot_water_heater_-_doug_kalmer.html

http://www.solarfacts.net/articles/diy/diy_solar_hot_water_heater_two_-_doug_kalmer.html

Gallery of Solar Homes- second one down-
http://www.jc-solarhomes.com/gallery.htm

SDHW and house-
http://community.webshots.com/user/sundug