Catastrophe Under a Hot Thin Roof

_It's summer and it is hard to ignore the heat out there. In this issue, Home Energy offers three ways that energy professionals are beating the heat. Mobile homes have long been known as air conditioning disaster areas; everything about their design makes them difficult to cool. "What Drives Cooling Savings in Mobile Homes?" on page 21 discusses the retrofits that can cut their cooling costs. We have published a few articles on measured savings from such retrofits, but many of the recommendations are still based on theoretical analyses. (Perhaps the Department of Energy will increase its activity, given that both presidential candidates are from states with hot summers.)

Another article reports that attic radiant barriers improve the performance of cooling distribution systems. The findings remind us that houses are indeed complicated, and that seemingly independent systems can be linked-sometimes a measure produces savings, but not where we expect them.

It has been a year since the Chicago heat catastrophe where hundreds died and countless more were immobilized. There were earlier, smaller heat disasters in Philadelphia and St. Louis-all cities known more for heating than cooling requirements. Cities already have response mechanisms for winter cold snaps when lives are threatened by lack of heat, but they are only beginning to develop comparable programs for heat storms. These heat catastrophes may be partly a consequence of urban heat islands, where city temperatures are higher than the surrounding countryside, due to dark buildings and pavement and the lack of trees. It would seem that the benefits of mitigating the heat island may be more than just reduced cooling bills and cleaner air.

A short article in this issue describes an interesting finding from the Chicago heat catastrophe: most of the Chicago fatalities occurred on the top floors of buildings. Those who died were generally old and weak, but the combination of heat buildup in the roof and walls and other aspects of the buildings and neighborhoods proved to be uniquely dangerous. What conditions turn a person's home into a death trap rather than a refuge from the heat outside? The article suggests that it is possible to identify buildings that may create dangerous thermal conditions. If so, then the summer heat storm response programs need to know which houses are potentially deadly. These homes could be retrofitted (probably with ventilation, insulation, and radiant barriers) to make them less like ovens. These activities should be incorporated into weatherization and community development programs. The winter energy savings could be significant, too.

Most of the fatalities occurred in poor, unsafe neighborhoods, where air conditioning was nonexistent and bad maintenance and fear of intruders (via the fire escapes) often kept the windows closed. In the end, we need to deal with these larger social and economic problems that prevent life-saving technology from being used. Otherwise we will have more catastrophes like Chicago's summer of '95.


 

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