Building Science 101

Hometrust takes a whole-house approach to home remodeling and improvements.  Our visit to your home includes several steps of investigation and testing to properly diagnose and uncover potential issues in order to recommend energy efficient improvements that will work. 

One of the most important building science principles that should guide home improvement decisions is the stack effect. 

As seen in this figure, warm air rises in a home.  This concept is not new.  What is important to know is that the warm air that rises, if left unchecked, leaves the house through the gaps in the ceiling.  What gaps you ask?  That is what home performance is all about!  Uncontrolled air leakage occurs when air moves through gaps or openings in walls, floors, ceilings, duct work, doors or windows and is often a major source of energy loss in homes.

As the warm air leaves the building, outside air is pulled in to replace the air that escapes.  This is a physics phenomenon.  The term stack effect comes from this dynamic that happens in the residential building, much like the characteristics of a  chimney that while in use billows smoke at the top while the fire pulls oxygen in down at the base.  

This pressure dynamic is what wreaks winter time havoc on energy bills and comfort and it also hampers summer indoor conditions as well.

The typical leakage points in a ceiling are fans, vents, light fixtures, plumbing holes, floors, walls, ceiling & the foundation.  These are all things that are hiding in plain sight!

1. Plumbing vent bypass
2. Chimney bypass
3. Attic access hatch
4. Interior wall top plate
5. Electrical box bypass
6. Panned return duct
7. Exterior wall top plate