Called in for a service of my humidifier, had very little knowledge of how the furnace works, coming from a apartment with centrally managed and maintained heating and AC system. Rafi came in and was very prompt, punctual, and patient - he answered all my questions and concerns, and filled in all the knowledge gaps I had. Though I called in for furnacing service, he gladly took a quick look at my humidifier without any additional charge to identify any issues with it. Gladly recommend him, specially to any first timers who have questions and our curious to know about these mysterious boxes in their houses (furnaces, central humidifiers, etc).