Saturday, July 7, 2007

Solar Screen

Update and bump:

As promised, the folks at North Solar Screen supplied my replacement parts. They were exactly right, and the installation took just a few minutes. Our screen is now complete!

With a month's experience (including quite a few 100°+ days), I can tell you that the screen makes a large difference in the perceived temperature of the room it shields. I haven't measured it, but my guess would be that the room used to be about 3° warmer than the rest of the house. Now it is about 2° cooler! Even more dramatic is the difference it makes to viewing our television – the screen is now bright, clear, and high-contrast even when the sun is at its brightest.

Original Post (6/17/07):

One window in our home has caused us problems ever since we moved in ten years ago. It's a south-facing window into our living-room, and it's big (8 feet wide, 4 feet high). The sunlight just pours into that room -- which is sometimes nice, as in the winter when you'd really like the extra light and heat. But most of the time, that light is annoying and expensive -- annoying because it's so bright it interferes with the television and gets in your eyes, and expensive because it's like having a 3,500 watt heater in a room you're trying to air condition.

Well, today I installed the cure: an exterior sun shade that blocks 100% of the light coming through that window. Because it's exterior, that means the 3,500 watts never enters our house, so our air conditioning bill should go down substantially. It raises and lowers electrically, using a radio remote control that works great from inside the house. Problem solved!

I bought the unit from North Solar Screen and installed it myself. Because the outside of our home is stucco, which is very rough, I decided to build a wooden frame around our window to protect the shade's fabric (you can see this peeking around the edges of the shade in the first photo above). I got a version that uses a 110 volt "Smart Motor" that fits inside the curtain roller, a remote control, 100% blocking Soltis fabric, and a cable hold-down system to better handle wind. The remote control receiver is built into the motor. The Smart Motor and the radio remote control are both made by Somfy, which is a French company (I knew this beforehand and bought it anyway <smile>). I'm quite happy with the unit, which generally is well crafted. Two little exceptions, both just annoying: First, the aluminum bar across the bottom was cut about 1/8" shorter than the fabric, and this prevented the black plastic end caps from inserting flush with the metal. Five minutes of work with a sharp knife cured that problem very nicely. Second, the fabric is folded over a plastic rod and welded at the bottom before the aluminum bar is slid over it. You can't see it in the photo, but this leaves an untidy-looking unhemmed fabric edge sticking up from the bottom on the inside, visible through the window. I've recommended to the folks at North Solar Screen that they find a way to improve this. The Somfy remote control was missing one piece of special hardware for its hanger, but I'm sure the North Solar Screen folks will replace that for me.

The installation process went smoothly with one notable exception and one ouch. The photo at right is a detail view of the motor end of the roller and the top of cable hold-down system (and my frame!).

The exception came when I tried to follow the instructions for programming the motor and resetting to factory mode. These instructions appear to be the first thing you're supposed to do, so I did as instructed -- applied power to the motor for ten seconds, removed it for two seconds, then re-applied power and waited for the motor to jog up-and-down. It didn't. The instructions tell you to repeat these steps until it does. I repeated, many times; still no jog. Thinking that maybe my counting off of seconds was imprecise, I located a clock (I don't wear a watch) and tried again. And again, and again, and always to no avail. This was very frustrating, as it appeared that my motor was completely non-functional. Just for the heck of it, I turned the sheet of instructions over to page two, and started the instructions for programming. The first step was to press and hold the "up" and "down" buttons simultaneously until the motor jogs. "Right," I thought to myself, "Like this is going to work after a bazillion failed attempts with the motor power." Wouldn't you know it? The damned thing worked on the first try, and all the rest of the programming worked as the instructions said! I'm not sure what happened here, but it sure made for a confusing and frustrating hour or so. But all is well in the end; it all works as it is supposed to work.

The ouch? As I was working, I laid down a socket wrench and didn't use it for perhaps 30 minutes. When I picked it up, it was hot enough to give me a nice red burn mark right across my fingers and palm. I measured the temperature later, as I was curious: 265 F! Yowee! Things get hot in our San Diego sunshine!!

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