Lew Harriman

No good deed goes unpunished. Tight houses have low cooling loads—a good thing from an energy
perspective. But with little need for cooling, AC systems don’t do a good job of controlling humidity. It can
be worse in humid climates when ventilation is continuous, because over the course of a year ventilation
humidity loads are 3 to 5 times larger than ventilation cooling loads. In other words, in humid climates
dehumidification needs to be almost constant—but cooling cycles are only intermittent. What to do?.. As
always, when in doubt; look at the data. We’ll look at real-world measurements of dehumidification loads
vs. real-time monitoring of cooling systems in 12 Florida houses, and then discuss some new ways to
monitor and quantify the risk of microbiological growth. Damp houses, geeky HVAC realities and nasty
mold and bacteria... what could possibly be more fun?