Hi, new to the forum; found through richsoil.com - great realist eco-site!
I just wanted to point out that cooling south-facing exposures is different than east / west facing exposures. An awning is definitely the best way to keep southern exposures cool in summer, and if properly built will still allow the warm (lower) winter sun to provide passive heat. Honestly,
trees are not the best solution for southern exposure protection because the hottest sun in the middle of the day still shines directly into the windows (trust me – I have 2 old trees 20 feet from the southern wall and one is angled very much towards the house (I think because there was an old hedge directly next to it as it grew) with the
canopy coming quite close to the house). Trees cannot be planted close
enough to the house to prevent this because their
roots will destroy the foundation. If you have a 3 ft high window then an awning that sticks out approx. 32 inches from the house and has a 9-12" drop (the lowest part of the awning, furthest from the window)
should provide protection from the hottest, most direct heat and still allow the sun's rays to enter in winter.
On the east / west exposures an awning is not the way to go, but a shutter-system is. The sun shines straight in, rather than from above, so shutters or even a
trellis a few feet in front (if on ground-level) will work. The "shutters" don't have to be solid, but can be slatted to allow ventilation. Shrubs / trees on the east-west exposures do help a lot.
The key is to block the excess heat before it enters the windows – blinds on the inside help, but they too heat up and hold that heat in, so blocking the heat from the outside is key. Insulated curtains are great in the winter – they do the opposite – they keep the heat inside the house.
Definitely get an attic exhaust fan to help cool the attic! Simply doing this means the attic remains at 100 degrees or so and therefore the excess heat in the house can rise into the attic and escape. Without proper attic ventilation the attic becomes saturated with heat (it gets trapped) and cannot absorb the heat from below. Heat naturally rises, so an attic exhaust fan just helps it along that much more. But you need proper passive venting for it to work (large gable intake vents, usually).
If you have ridge vents and soffit vents, they will interfere with the attic fan. They are designed so the soffits intake fresh outside air and exhaust the hot attic air through the ridge vents. New construction requires this; old houses usually lack this. Adding an exhaust fan will actually reverse the flow of air and it will suck the air in from the ridge vents – very bad!
What I did (ok, I am still in the process of this messy job) is I installed an exhaust fan in a gable vent that faces west. I have another gable vent that faces east, and two huge old gable vents facing south and north that are actually a foot lower than the new attic. These 3 gable vents are the intake feeds. (We put on an extension and the new attic floor is 8 ft. above the second story, whereas the old “attic” crawlspace was 7 ft. above the original second story). The new attic has soffit vents at the eaves (bottom of roof) and a ridge vent. What I am doing is “closing off” this airflow from the actual attic space (where you can stand), but still allowing the soffit-ridge airflow to cool the actual roof itself (plywood decking and shingles). I am doing this by furring out the inside of each roof joist bay with 2x2’s and stapling perforated (breathable) radiant barrier to it, thereby leaving a 1.5”-2” airspace between the roof deck and the radiant barrier so the air from the soffit goes straight up and out through the ridge vents. The radiant barrier is basically a replacement for those Styrofoam baffle things you use before insulating roof rafters. The radiant barrier also reflects excess heat away from the attic, whereas that Styrofoam does nothing but create an airspace. The reverse air-flow is stopped, and the roof itself should last longer because the soffit-ridge vents are only cooling it, not the entire attic. Because I have 3 gable intake fans there is plenty of airflow for the exhaust fan. I have an electric hardwired fan with a humidistat control for the winter. I was going to go with solar, but after reading many reviews, I would have needed at least 2-3 solar fans to provide enough ventilation.
We plan on adding a whole-house fan as well. This will be located at the top of the staircase in the second floor ceiling and it will exhaust the warm air in the house into the attic. This is why we had to install a powerful attic exhaust fan – to exhaust all the air that will eventually be entering the attic. Hopefully this will eliminate all need for air-conditioning. The house originally had an old gigantic one, and my mother swears that it worked great back in the day, so eventually we shall see. Whole-house fans are expensive, though, especially a large and quiet one. Right now we have window air-conditioners, but only turn them on when it gets unbearably hot (over 85 degrees over a few days), and because they make me sick I rarely keep them on at night.
Basic passive cooling is obtained by simply opening your windows from the TOP, not the bottom – because hot air rises. Adding a window exhaust FAN to one of the windows at the top helps tremendously! If there are many windows in the room I usually crack one at the bottom and the rest at the top for more cross-ventilation. We also added ceiling fans to most of the rooms – helps a LOT!
Also, if you happen to live in an old house with solid PLASTER walls, DO NOT destroy them and replace them with drywall!!! Seriously, my original house has solid
wood 1x12 shiplap sheathing covered with tarpaper and cedar shakes, and inside is solid plaster on rock lath that is almost a full inch thick – the living room / breakfast room is the warmest room in the winter, coolest in summer – NEVER needs air-conditioning! We even disconnected the radiator that was in the kitchen. The new “modern / high-tech” drywall - insulation – plywood sheathing is a JOKE!!! It is FREEZING in winter, deathly hot in summer! That’s all the proof I need that thermal mass truly works! Even better, it is soundproof – WITHOUT insulation! Seriously, I put R-32 in the new addition ceiling between the first and second floor, but you can hear EVERYTHING! Drywall sucks! But, if you leave the scraps outside in the rain and remove the paper you can crush it up and add it to your clay soil to soften it (gypsum)!
A tip on flooring – the floors above the full basement are warm in winter, but over the crawlspace (1950’s addition) were always freezing. The new addition is also on a crawlspace, and we took up the old oak 1950’s floor (to be re-used in the old kitchen that will eventually become a butler’s pantry / laundry room), and just installed a new wood floor across the new/old addition. Normally wood floors are installed over resin paper or 15 pound tar paper. But, we had our Sassafras custom milled and they told us to use 30 pound felt/tar paper underneath. We did. Wow – what a difference! It has totally eliminated the draft from below! The insulation in the 1950’s crawlspace was installed in the 1980’s (silver-faced), and that wasn’t changed, so the thicker felt/tar paper was definitely what made the difference.
BTW: Sassafras is a
native, very
sustainable tree – it forms colonies! I didn’t like new oak compared to the antique oak in the original house, so when looking for wood floors I found a place in Indiana that mills flooring in all species, including Sassafras. It is a softer wood, just a bit harder than yellow pine, so many people don’t think of it for flooring (or anything, for that matter), but there are pine floors in New England that have lasted over 200 years, so softness didn’t bother me. Also, we had a freak Nor’Easter last spring during which an ancient Sassafras tree of ours finally fell (well, the lower 25 feet stayed in place, but the top 40-60 feet fell straight across my
yard, taking out part of my birch tree cluster along the way. I was sad, and although I have a few babies growing, I decided to honor that great old tree with a Sassafras floor. Ironically, the mother tree came back to life and now is covered in new growth at the top! At the base she is approx. 3 ft. in diameter (I haven’t measured her circumference, though). It is a gorgeous floor! And smells awesome when cut!
Ok, I’m ending now as I’ve gone way off topic!