Case Study on Air Sealing

We performed an energy audit on a historic home in the Forest Park neighborhood of Birmingham in the summer of 2015.  The clients were having trouble keeping the home cool enough to be comfortable, and there was a front room with lots of windows that never got cool enough to be in.  Their AC system seemed to run constantly and was not able to keep the house at the desired temperature.  However, the basement/crawlspace was very comfortable…because that is where the duct work was located, and it was leaking very badly.  In the attic we found some common culprits of energy inefficiency.

Attic Culprits

There were several large, open chase ways exposing the backs of interior walls with no insulation.  These allow hot (or cold) attic air to radiate through the walls and into the conditioned living space.  We also found plumbing and electrical penetrations that were unsealed and allowing unconditioned air to enter the conditioned space.  Light fixtures, especially can lights, often leak air from the attic into conditioned space causing excess heat (or coldness).

We completed our audit and prepared our report with the prioritized and customized scope to improve the comfort of their home. Our top two priorities were sealing the duct work and AIR SEALING.  Insulation was a close third, but due to budget constraints, the clients decided to have us do the duct sealing and the attic air sealing.  And guess what?!  They could immediately feel a huge difference in the evenness of the cooling throughout the home – even in the front room.

Balloon Framing

This home is not unique in terms of air flow and leaking ducts.  It was built with balloon framing, which means wall cavities run from the unconditioned crawlspace, past the conditioned spaces, all the way up to the unconditioned attic.  This was a popular way of building before the introduction of central heating and cooling because balloon framing causes stack effect and air flow for drafts and natural ventilation.  Since the introduction of central heating and cooling, we work to stop this venting so that the HVAC system works more efficiently and the walls do not radiate hot or cold air from outside.

If you are unsure if your home is properly air sealed and performing at its best and most efficient state, call us to investigate (Birmingham area: 205-314-3500 or Gulf Coast area: 251-615-1330).