New Jersey home inspectors should understand the importance of the stack effect in winter months in homes that they are inspecting in NJ. As warm air rises in a house it exists or leaks out of the upper floors and especially the attic. New air must enter to replace the upper air loses. In the average house roughly one half of the air in the home exists or escapes each hour out of the upper floor or attic of the home. This escaping air creates a suction effect that draws air in at the lower levels. Air has to enter to replace the air lost at the upper floors. In older homes this air leakage can cause the air in the home to be a complete air exchange each hour. This air leakage crates a condition called the stack effect. The stack effect is a chimney like effect that creates air flow from the lowest portion of the house to the highest. Air from the lowest level crawlspace or basement is then drawn to the upper floor and then to the highest floor in the home. This air as it rises up gets mixed with the other existing air in the home. It is known that up to half of the air that occupants breathe in the first floor of the home originates from the basement or lower level of the house.
As a result, is very important that the air quality in the basement is good because you are essentially breathing about half of it in your living space. If there is high humidity or mold in the basement or crawlspace, then mold and humidity will be higher than expected in the main living areas of the home as well. If there are damp odors in the lower level, there is likely to be damp odors in the living areas too.
Air flows upward in a home due to a natural forces. warn air rises and exits openings in the upper levels. While this is occurring, cool air enters the lower level through cracks and opening in the home’s foundation and structure. Warm air is less dense than cool air, so it rises. The effect is like that of a chimney. One of the issues with the stack effect is that as the warm air rises it brings with it humidity from the basement or crawlspace. NJ home inspectors should be able to explain the many issues that a damp lower level can have in a home. The effect of high humidity can be dampness or odors in the home, condensation forming in the attic, mold forming in the attic, condensation on interior windows, increased heating and cooling costs, lower expected life expectancy of the roof covering, increased vulnerability to allergens especially dust mites.
Dust mites are the number one indoor allergen and are the concentration of mites can be greatly raised in homes that have damp lower levels or basements. The element that effects health in a negative way are the dust mite droppings. Dust mites absorb moisture from the air they don’t actually drink water. When humidity levels are over 50% dust mites can thrive. The best way to combat the dust mite is to make sure that the basement of the home remains dry and has humidity levels below 50%.
There is also a reverse stack effect that occurs in the summer months where cold air is forced down to the lower levels of the home. for this discussion we are focusing on the winter stack effect.
New Jersey home inspectors should understand the importance of the winter stack effect in a home. The stack effect plays a major role in the comfortability, health safety and heapability of a given home. It is imperative that the home have a dry basement or crawlspace in order to help avoid significant problems with high humidity and mold in the home. NJ home inspectors should inspect for evidence of wet or damp basements and educate their clients accordingly on how to correct for those conditions.