In the energy efficiency world, air infiltration in buildings is the elephant in the room that no one is talking about.  We all know it exists, we all know that it can kill energy efficiency in a building….but we’re not doing enough about it. So what exactly are we talking about here?  Air that infiltrates into buildings has always been a bit of double edge sword.  Its effects can range from annoying, like that cold draft that we can never seem to pinpoint, to being helpful as a method to supply fresh ventilation air to a space.

So, what’s the big deal? Well, the big deal is that unconditioned air that leaks into a building is extremely costly in terms of energy consumption.  Air in our buildings costs money to either heat or cool.  If we allow excessive amounts unconditioned air to enter our buildings it means that the conditioned air that we’ve already paid to heat or cool is heading outside.  Not a great way to spend money if you ask me.

Recent studies have shown that we could save as much as 20-30% of the energy associated with heating and cooling by reducing the amount of air infiltration in a building. We do have the ability to measure how much air is infiltrating into a building.  This is accomplished by means of a blower door test.

A blower door test consists of a series of fans that can both pressurize and depressurize a building to a prescribed pressure.  Airflow that is coming through the building is then measured with a digital manometer.  This test combined with thermal imaging makes finding deficiencies in the building envelope easy.  However, this type of testing in the construction industry has very much been the exception and not the rule when it comes to common practice.

The construction industry is very fickle when it comes to change.  It’s pretty well frowned upon.  What is considered tried and true is embraced and new ideas and methods are often looked at with suspicion.  Sometimes it’s for good reason, there’s a tremendous amount of liability involved with being in construction. Building and energy codes have not required this level of scrutiny in the past so a test like this was usually considered something nice to do but not a necessity, When budgets got tight extra testing was “value engineered” out of the equation.

However, construction and design professionals haven’t been very good in the past about considering the long term operational costs associated with a building long after they are no longer involved. An interesting thing happened as part of the ARRA government stimulus.  Any state that took money from the stimulus for energy related projects had to agree to update their energy code to the IECC 2009 or an equivalent.

The City of Chicago elected to take a slight delay in updating their energy code and offered to adopt the IECC 2012 in return for their delay.  This new energy code goes into effect for the City of Chicago on January 1st, 2012.

The IECC 2012 is the first energy code to have building shell airtightness requirements associated with showing compliance to the code.  So, as of the first of next year, any new construction or major rehabilitation commercial project in the City of Chicago will be required to show that the building shell meets the tightness requirements prescribed in the code.  One method for doing that is with building shell testing. This will no doubt be a wonderful opportunity for firms like mine to help building owners make greater strides toward long term energy efficiency.