"Dear Mr. And Mrs. Jenkins, On this past Saturday your son was at my house in order to clean and inspect our furnace. I just wanted to write a note to let you know how impressed I was. Not only was he extremely thorough and professional but he was also very polite and personable. I just wanted to let you know our experience and let you know that I am very happy that we became customers a year ago. I would recommend you to anyone in need of heating service. Thanks for your time and have a nice week."