These are some excerpts from a recent discussion in the Home EnergySolutions Yahoo discussion group. http://tech.groups.yahoo.com/group/homeenergysolution
The idea is to provide shading for the windows or walls behind the trellis and prevent direct gain from the sun. This will make a significant difference in heat gain, particularly in the case of windows. Painting the wall white or a very light color can also be helpful.
If anyone has pictures of these schemes (or others), please send them in.
Many more cooling ideas here ...
Using Sunflowers as a screen:
"Just a little side idea you might be able to use - the last 2 summers I've
planted a double row (off set spacing) of Sunflowers along the south wall
of my house, and by this time of year they're 15 feet tall and really seem
to have an impact on keeping the wall cooler ... (plus it's fun to watch
the gold finches playing in them) Yes it's not a perfect or long term
solution, but might be worth a try for a little digging in spring and few
bucks worth of seeds. With the off set spacing - they take up less than a
3 foot wide strip along the side of the house - so even good on a small lot."
"Just a couple more notes on vines and sunflowers ...
Perennial deciduous vines, on as open a weave of lattice as possible (maybe
something like chain link fencing) and set back at least a foot or two from
the house might be a good option (although slower and more expensive than
sunflowers) if you'd like a more permanent solution and still be able to
keep some of the heat gain in winter. The space between the house and
vines not only protects wood/gutters etc, but also allows air to circulate
through the shaded area. If it's dry heat - and water's available - hosing
down the vines can add an element of evaporative cooling too.
Maybe the first year or two you could plant vigorous annual vines to fill
in while the perennials are establishing themselves. Morning Glories and
Moon vines are a nice mix (moon flowers open up a night and smell WONDERFUL
if you have a long enough season to get them to bloom) Maybe some squash,
pole or runner beans for edible side effects? All of course depending on
One quick down side of Sunflowers is that they don't make good neighbors"
Trellis That Hangs From Eaves:
Hang the trellis from the house eaves -- possibly using a header board that is screwed to the eave rafter ends.
"We actually suspended the lattice from the eaves of our house and grew the vines up to it. This avoided contact with the ground and when it came time to paint, we unhooked it and just laid the lattice forward on the ground. We used trumpet vine, which worked great, dense vegetation which really soaked up the heat.
Trellis Set Off From House On Posts With Walkway Behind:
"Depending on your layout, you could sink some posts 3-4 feet from the
house so you could walk behind it. Put the screen on the posts, plant
in front, and then cover or shade with slats or lattice on the part
between the house and the posts, creating a pergola or covered walkway.
The effect should be pleasing and the shading would work just as well at
reducing the load (assuming your posts are tall enough). Lay a bed of
sand in the walkway to raise it a bit, lay a few slates for stepping
stones, and then seed with white dutch clover, which won't grow tall,
doesn't need mowing, and will keep the area from becoming a bog."
Thanks to the folks at HomeEnergySolutions for the good ideas!!