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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>A PTAC is typically what you would think of as a window air conditioning unit. A PSZ is also called a split system and would be installed using duct work. I believe the main difference is that the PSZ has duct work and is a split system and the PTAC has everything contained in a single unit. It depends what kind of residential building you’re talking about but for homes the PSZ would certainly be more common. I think PTACs are most common in buildings which did not originally have air conditioning installed because it is easiest to add later since there is no central system.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I found a few topics in the equest help which might be useful. If you search for “PSZ” there is an article called “System Type = PSZ” which gives a description of PSZ. For PTAC there is an article called “PTAC with Air-to-Air Heat Pump:” which gives a description of PTAC. They both also have pretty good diagrams.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hope that helps.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Michael<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> equest-users-bounces@lists.onebuilding.org [mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Vipin Sharma<br><b>Sent:</b> Monday, April 18, 2011 2:26 AM<br><b>To:</b> equest-users@lists.onebuilding.org<br><b>Subject:</b> [Equest-users] difference between PTAC and PSZ<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0><tr><td valign=top style='padding:0in 0in 0in 0in'><p class=MsoNormal>Hi...............<br> what is the difference between PTAC and PSZ.<br> what AC ia used for residential purpose.<br> Thanks in advance<br>Regards<br>vipin sharma<br>student <br>Energy Engg.<o:p></o:p></p></td></tr></table><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div></body></html>