– depends with a mechanical procedure to move air out and in. Historically, properties have already been manufactured to foster pure air flow, leaving more mature homes with gaps, cracks and opening doors and windows for air to pass through. Vents/Registers: Vents and registers are opening in partitions, flooring, https://hvac52838.59bloggers.com/31813209/the-smart-trick-of-hvac-that-no-one-is-discussing