Changes in HVAC system design or operation
which reduce sensible heating or cooling requirements
may increase latent heating or cooling energy which offsets
any energy conservation advantage. This is particularly
true of economizer cycles (ß10.5.5). The use of cool,
but humid outside air in an economizer can actually increase
energy consumption if dehumidification requirements
are increased. For this reason, the only reliable
type of economizer control is enthalpy control which prevents
the economizer from operating when latent cooling
requirements exceed the savings in sensible cooling.