For this call we performed a super tune-up. I noted that the unit did not have a return plenum which is now considered a code item and that the homeowner is on a outdated membership. I recommended a membership conversion and also considering adding a return plenum for efficiency purposes with better static pressure and option for filtration upgrade. Homeowner was not present so I presented to their niece who would speak with home owner about the recommendations and give a call back if they had any questions. I left the system off as found on entry. Thank you for choosing Comfort experts, have a great day!