The classic example of old, energy-wasting buildings in New York is residents opening their windows in winter to let the heat out. Landlords must set the thermostat high enough to keep the coldest apartment warm, which makes the warmest units hot. Some folks call this the “lowest common denominator problem.” Many newer apartment buildings, however, have a different energy-wasting issue that’s not so obvious: Their HVAC systems are running all the time, even when they are not needed. These systems have various features that prevent units from getting too hot or too cold, so nobody’s opening windows. But energy is […]

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