Air conditioning

Why is it that in every office building I know in New York, as soon as the outside temperature reaches about 70-75 degrees, the indoor temp begins to hover somewhere around 32? Aren't we supposed to be thinking green these days? I hate having to contemplate one outfit for getting to work every day, and then factoring in a heavy outer layer so that my hands are kept sufficiently warm to use the computer or dial numbers on my phone. As summer goes on, my office begins to look like an outpost of the Salvation Army, strewn with fleeces and hooded sweatshirts, none of which are actually appropriate for the office. Lay off the A/C, Rockefeller Center, I beg of you!