22 A SHRAE Jou rna l ash rae.o rg J u n e 2 0 0 9 Climate Change and IEQ By William Fisk, Fellow ASHRAE

or measures are identified within the Advanced Energy Design Guides available from the ASHRAE Web site. Table 1 is not meant to be exhaustive; however, it does identify the broad range of potential changes in HVAC that will affect the practices of the ASHRAE membership. Examples include: • Increased use of mechanical ventilation systems in houses with more airtight envelopes; • Smaller capacity HVAC systems with a larger ratio of latent to sensible capacity for buildings with more ther-mally efficient envelopes and lower internal heat loads; • Increased use of low energy cooling systems such as those with evaporative cooling; • More and new types of demand controlled ventilation, heat recovery, and gas-phase air cleaning to reduce out-door air (OA) ventilation energy requirements