Thin clients are not without their problems and, as I've said before, are hardly a panacea for every computing problem we face in Ed Tech. However, as I sit baking in my room and temperatures outside come way too close to 100 degrees for my delicate ex-Seattlite sensibilities, one particularly nice feature of thin clients becomes quite clear: they generate very little heat and have minimal cooling requirements.
The room where we have our CAD lab running standalone desktops (relatively efficient desktops with LCD monitors, at that) has the AC cranking as we speak (it's about 8:15 in the morning here in Massachusetts). The three labs with thin clients all contain more computers, but the air conditioning isn't running (one room doesn't even have an air conditioner).
These little guys use a tiny fraction of the power of a standalone desktop and, with no moving parts, remain cool to the touch. The same case could be made for netbooks, especially those based upon Intel's new Atom processors. Many have flash-based hard drives and little or no active cooling. Again, they generate minimal heat and use very little energy and, with an RDP client, could easily access a Windows desktop if you were running Terminal Services.
This isn't just about being green, folks, much as I love hugging trees. It's really about the practicality of running and cooling computers in a variety of settings and conditions. We can't dump all of our standalone machines, but a tech refresh that didn't look at alternatives to desktop computers is doing a disservice, both to the environment and the students trying to stay cool in their classrooms.