A portable air conditioner (PAC) is similar to a window (room) air conditioner. However, instead of being installed in a window, PACs are floor-standing units usually outfitted with wheels to allow them to be easily moved. PACs use specialized flex ducts to exhaust the hot condenser air through a window. PACs may be either single-duct units, or dual-duct units, where the additional duct brings in some of the condenser air from outside.
THE POTENTIAL STANDARD:
No national efficiency standards exist for portable air conditioners though a DOE rulemaking is currently underway. DOE published a proposed rule in April 2016 and expects to issue a final rule by the end of 2016. DOE published a test procedure final rule on June 1, 2016.
According to DOE, PACs are a fast growing segment of the market with current shipments of about one million units per year. PACs are much less efficient than room air conditioners because much or all of the condenser air flow for PACs is drawn from the conditioned space and exhausted outside. This process creates a negative pressure, which results in infiltration of hot air from outside. DOE's preliminary analysis found that significant energy savings could be achieved by adding a second duct to single-duct units and by increasing the portion of the condenser air that is drawn from outside (rather than from the conditioned space).