This Old House: Heating, Ventilation, and Air Conditioning by Richard Trethewey with Don Best (Little, Brown and Company, 1994; 800/759-0190). Softcover, 71/2x10, 255 pages. $24.45. The television show This Old House is undoubtedly one of the most popular educational TV shows of recent years. Viewers watch many different aspects of home construction and renovation, including the often overlooked heating, ventilation, and air conditioning (hvac) systems. The show is well known among its viewers for presenting the latest innovations in residential building technology, tempered with discussion of practicality and cost. Richard Trethewey is the mechanical systems expert on the show. He is frequently consulted for practical advice on how to properly equip buildings for yearround comfort. His book, with co-author Don Best, is in my opinion one