John W. come to my home to check the operational status of two HVAC units as part of My Plumber's winter check-up. John was very courteous, knowledgeable and professional. He explained what he was testing, why he was testing the particular items and the significance of the test results. He eagerly answered my many questions including those about HVAC systems I am considering purchasing in the future. John represents the kind of customer service that is becoming harder to find in the USA. Great job!