Moisture and Energy Conservation

Several articles in this issue deal with the vexing problem of moisture in homes. Excessive moisture is, at best, a nuisance and, at worst, the source of catastrophic building failures. The problem appears in Saskatchewan winters as well as Florida summers. In many cases it also either causes or contributes to a range of health problems--from minor thermal comfort complaints to full-blown allergy attacks. Restoring proper humidification often yields visible or sensible benefits: less condensation, sneezing, or clamminess. These improvements are not always quantifiable but the occupants sure appreciate them ("I can breathe again!").

The physical explanations for high moisture, be it excessive humidity or condensation, are often subtle and complex. It's no surprise that the average contractor is baffled by such problems, and that, if he or she succeeds in solving the complaint, it is more often by luck than by skill. A systematic solution requires knowledge of the building envelope, the appliances, the HVAC system, and the physical principles of heating, ventilation, and air conditioning. Moreover, it requires an understanding of how these systems interact (and what happens when they interact unsuccessfully). People who understand these factors have no trouble finding employment. Indeed, it was hard getting the experts to write these articles because they are so busy consulting!

A theme running through the articles in this issue is the connection between moisture and energy conservation. Air sealing, insulating, duct sealing, and adjusting the heating or cooling system can all affect the movement of moisture in and through a house. Sometimes the efficiency measure solves a problem, as when a correctly sized air conditioner reduces the humidity in a house. At other times, a measure intended to save energy will create a new moisture problem, or worsen an existing one. For instance, air sealing a house with high indoor moisture production can trap water vapor that was previously able to escape through all the leaks. Practitioners should not depend on luck to choose the measures that will have positive results, and they no longer have to. Current tools and practices, including the blower door and duct tester, allow the air sealer to determine a house's pressure dynamics, key information for preventing or solving moisture and indoor air quality problems.

This linkage is important as the energy conservation industry expands into the broader area of providing higher-quality living spaces. There will be cases where the energy-saving benefits alone may not be sufficient to justify a measure, but the comfort improvements may tip the balance. The key, however, is knowing when a conservation measure will solve the problem. This is why you should read all the articles in this issue.