Modified ducts to upstairs system to eliminate pressure imbalances between rooms and turbulence causing elevated humidity and condensation on supply grilles. Added a return duct to the guest bedroom, moved the return and thermostat for the master suite to achieve uniform air distribution. Straightened out the supply ducts and sealed all duct fittings from above and below. Replaced faulty thermostat which was not bringing the AC system on often enough to properly condition.