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Water Cooling...
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Q: Dear Wiz:

I have seen several systems available for spraying water on the roofs of livestock containment buildings to lower interior temperatures. Do you know of any systems available for residential use? Have any studies been done that show if these systems are effective for lowering air conditioning costs?

A: Dear Reader:

I am not aware of any kits for this type of application for homes. I am also unaware of any studies analyzing the effectiveness of this type of cooling method. However, I am aware of a shopowner who has constructed and installed a system used on the roof of the shop. He has told me how happy he is with the results, and quite surprised at how effective the system is in keeping the shop cooler.

The Energy Wiz!
The Energy Wiz!
A system of this type for cooling purposes would make sense. When a pound of water evaporates, the process also eliminates an estimated 1,000 British thermal units (Btus) of heat.

A fairly simple roof water spraying system could be constructed using sprayer nozzles available at farm supply stores. If the system was mounted at the peak of the roof and delivered a few pints of water every 15 minutes, it should be effective. The system would also need a timer. One word of caution: make certain there are no holes in roof that would allow water to seep through.

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