The House As A System, Part II

In 1994, one of my editorials as chief editor of Contracting Business magazine entitled, The House As A System, was also one of the first articles written in an HVAC industry magazine that identified the connection between the entire HVAC system and a home's envelope. At the time, research and the practice of "Building Science" were just in their infancy, but many people began recognizing the importance of interactions between the envelope and the HVAC system.

Educators, like National Comfort Institute's Rob Falke, were pioneering new methods of learning and teaching that revolved around the idea that the HVAC system was much more than just interconnected boxes (like condensing units, air handlers or furnaces, and coils). We began to truly understand that if the complete system wasn’t installed, tested, and balanced properly, we would have major losses in comfort and efficiency — as much as 30 to 40%. It's more about the "system" than the "boxes" (See, Sell a Well-Performing System, and Stop Swapping Boxes). The 1994 article identified the importance of each of these disciplines and the need to bring them both to the homeowner to provide the best of all worlds in terms of comfort and energy efficiency.

At that time the building performance industry and HVAC industry were somewhat at odds (and are still not completely in harmony today). If you asked a building scientist how to make a home and/or HVAC system efficient, he would tell you if you seal everything and get the envelope tight you could heat the house with a candle and cool it with an ice cube.

If you asked a student of HVAC system performance how to make a home efficient he would tell you if you installed properly sized equipment correctly and made sure you had a tight, well insulated, and balanced duct system, you didn’t have to worry about the home being too tight as you would hardly lose anything through the envelope.

Well, all kidding aside, they were both right, and both wrong. The real answer is, "It depends!" The bottom line is you don’t have to choose one over the other, rather you should identify the right combination of building solutions and HVAC solutions based on "that" particular home in that particular geography with its unique flaws, conditions, and needs.

House and HVAC As A System.
This is why, as an expert HVAC practitioner, you must be well-educated and trained in both whole house and whole HVAC system philosophies. Too often, in both disciplines we tend to gloss over things, or use rules of thumb. By understanding how to test both the home and the HVAC system, you’ll know in each instance which remedies will give your customer the most bang for their buck.

Sound confusing? It can be. But the good news is there's plenty of help out there. Just be careful you're not dealing with narrow minds in either case. Don’t forget the old adage, "If you're a hammer, every thing looks like a nail." If you get your training from an entity whose experience is mostly in building performance testing and renovation, you may get a skewed view of the causes of, and solutions to comfort, performance, and efficiency problems. By the same token, if your education is only HVAC-based, you may miss important building issues that might keep the HVAC system from ever being efficient or comfortable enough. Are you starting to get the picture?

It's Like Learning To Riding A Bike!
At first, you may not always choose right. Like learning to ride a bicycle, you will fall down a few times, you may skin your knees, or even break a bone, but you have to get right back on it and practice, practice, practice, until you become a true student of both building and HVAC system performance. Doing it right doesn't happen overnight.

One of my favorite sayings is, "No one ever learned how to ride a bicycle at a seminar." How true this simple statement is, but it still takes disciplined training and ongoing education to get and keep you there. The rubber then hits the road in the field where on job after job, test after test, you and your field people learn more and become truly proficient.

Beware of "quick fix" classes, shortcuts, and rules of thumb. Yes, it's important to take the initial training, but it’s the ongoing support that will keep you on track and, as much as possible, out of trouble.

If you haven't yet invested in learning how to truly provide delivered performance, it's not too late, but don't delay. Things are moving very fast, and those who decide to not change, and want to keep being hammers will eventually run out of nails.

If you’d like to download a copy of the original, "The House As A System" article from the April 1994 issue of Contracting Business, go to

Dominick Guarino is Chairman & CEO of National Comfort Institute (NCI), (, an international training and membership organization with nearly 500 members. NCI specializes in Performance-Based Contracting™. The organization’s primary mission is to help contractors grow and become more profitable. Email him at [email protected] or call 800/633-7058.

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