Arrived at customer's house for system not cooling efficiently. On arrival customer showed me to air handler unit. System was running. Went out to condenser and system was running. Hooked up my gauges and pressures and readings were showing low freon. Pointed out to customer and suggested we add freon. Customer agreed. Added 3 pounds and system now looking fine. Suggested customer sign up with tap plans so we could build a history on both units. Customer agreed. Signed up for plan. Collected payment and signatures and left. Customer happy.