This session explored the relationship between home envelope tightness and energy performance and the policy implications of stronger energy code requirements. Focus was given how to attain tighter envelopes and the impact of envelope tightness on HVAC load calculations, the relationship between envelope tightness and intentional ventilation, and a few lessons learned from the Duct and Envelope Tightness (DET) verifier program. New technologies and approaches enter the marketplace every day. This session was designed to help policy makers, builders, designers and code officials identify current code requirements, best practices and missteps to avoid when creating tighter envelopes and considering new code requirements.