Reinforcing the pressure barrier in low-rise multifamily buildings can increase occupants’ comfort and savings.

Multifamily buildings vary widely. They range from houses divided into three apartments to 500-unit high rises. So a weatherization project must be tailored to fit the personality of the building. The first order of business is to assess whether a particular building should be treated as a system or divided into floors or units.

This assessment should take into account how air moves through the building. If there is a lot of air movement between floors, the building starts to act like a tall house. If each floor is sealed off from the others, the building resembles a lot of houses stacked on top of one another. To determine which type a given building is, gauge the stack effect by looking at the temperature differentials throughout the building. Are the top floors overheated while the bottom ones are too cold? Other helpful measurements include pressure differentials and physical tests such as opening a window on the top floor and checking for a strong steady gust of air moving out of it.

Read more on Home Energy Magazine’s website