Perform fall service on 80% downflow Lenix furnace clean the flame sensor checked amps on motors performed a safety inspection checked all electrical components the system is operating correctly at this time also inspected the insulation in the attic and found it to be in adequate and informed customer about ogne rebate for bringing insulation up to par. Did a ductwork calculation and found system lacking in return air the system is a four ton which needs 1600cfm and is only being supplied with 1275 CFM system is lacking 325 CFM of air which is almost a whole ton of air customer says master bedroom is too hot/cold increasing return air will also increase the supply air because you can only push the amount of air that is brought back through your return. (If you have a four ton system but aren’t bringing back four tons of air you don’t really have a four ton system. )recommend increasing 14 metal pipe to an 18 inch. Also asked customer about the dryer taking to long and she said ye