I've never been one for extreme sports of any kind; but here's an "extreme" type challenge I did participate in last winter - not heating my office.. at all. It's extreme to me as I despise being cold and much of my life is spent in this room :).

Granted, temperatures in this part of Australia rarely get down lower than a few degrees above freezing overnight and winter daytime temps get up to around 12-15 degrees celcius (53 - 59 degrees Fahrenheit); but it still feels mighty chilly when you're sitting on your butt and tied to a desk for 12 hours a day.

My reasons for this exercise were many - curiosity to see how much I had softened up since my laboring days, some of it training for a project in the time ahead and for energy saving purposes.

I didn't weaken and during the full 3 months of winter, I managed to save around 540kw in electricity that would have usually been used in heating to a "warmish" level. If I were sourcing my electricity via coal-fired generation; that equates to around 810 pounds of carbon dioxide emissions saved.

I'll probably do it again next year, but be better prepared clothing-wise. It's easy for me to say that now, it's summer here in Australia and currently we're sweltering in 39°C (102°F) temperatures :)

While this mightn't be a challenge you'd like to try for various (and often very good) reasons - lowering thermostat levels even just a few degrees can save you big on energy - which reduces impact on the environment and puts dollars back into your wallet.

According to the US Department of Energy, You can easily save energy in the winter by setting the thermostat to 68°F (20°C) while you're awake and setting it lower while you sleep or are away from home. Just by winding back your thermostat 10°–15° for a period of 8 hours overnight, you can save about 5%–15% a year on your heating bill - that also translates to a whole stack of resource and carbon dioxide savings depending upon your source of heating.