Our Poor Relative HVAC

By Hal Alles

Most of us have a poor relative. They are good people and try hard, but some how they never get respect, a break or get ahead. Of all the trades in the building industry, HVAC is our poor relative. Next to keeping dry, keeping warm is the most important thing in a shelter. For our ancestors, using fire came shortly after using caves. Why is it that today HVAC has such a lowly status that a $1 million house has an HVAC system that costs less than $10,000, essentially the same system that the most basic house has? This is especially odd considering how on a customer satisfaction survey, a question like "How is the temperature control in your new home?" always gets the lowest score. Why is it that when a home buyer adds $100,000-plus in options to a home, $0 goes to a better HVAC system?

We all accept that people will buy at least some clothing for looks rather than comfort. Women's shoes are a good example. A little discomfort to make a fashion statement at a party is worth it to most people. But when they get home, they can get comfortable. When a home is primarily designed to make a "design" statement while neglecting comfort, where does the homeowner go after the party to get comfortable? Worse yet, the home may not be comfortable during the party. Even in modest homes, the living and dining rooms may only be used when entertaining. However, the HVAC system is never designed to cope with many people in these rooms. It is ironic (sad, frustrating, maddening, etc.) that the only times these rooms are used, they get uncomfortable.

Why does the average America house-hold use about 3.5 times as much energy for conditioning as the average Japanese household? The average Japanese home is about half the size of the average American home, but this can only account for less than half of the difference. The rest is because the Japanese only condition the rooms they are using. Americans condition every room all of the time, even though most of those rooms are unoccupied most of the time. We control conditioning with a single central thermostat that ensures some rooms are over-conditioned while others are under-conditioned.

Most energy codes and rebate programs are obsessed with controlling lights. I suspect that is because as children, we were all yelled at about turning off the lights. But what about HVAC? It typically takes more energy to condition a room than to light it. There are dozens of light controls in a home for every HVAC control. If each room needs a light controller (switch), why doesn't it need an HVAC controller?

This is a typical poor relative story. Despite the logic, despite the advice, despite the head shaking and well wishing, they somehow never get respect, a break or get ahead. The intent of this department is to focus on our poor relative HVAC, to understand the problems they attempt to solve, to understand their predicament, to offer support and to actually offer some solutions. I hope you find this department interesting and useful.

March 2007 Builder Architect Edition Issue

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