When patients at a surgical hospital in Amman saw protective coatings being installed over the windows, some assumed the glass was being reinforced against potential bomb blasts. Most of the people there had come from war zones in Syria, Iraq, Yemen, and Gaza. They might reasonably see windows in an eight-story building as a shatter hazard.

In fact, the window films were added simply to absorb the strong Jordanian sunlight, making the hospital's rooms cooler and more energy efficient. Energy demands were growing at the rehabilitation facility, a quarter-century-old hospital reopened in the fall of 2015 by the medical aid nonprofit Doctors Without Borders/Médecins Sans Frontières (MSF).

As the world faces record numbers of displaced people, humanitarian groups have more incentive than