When You Build it Tight You Have to Ventilate Right

Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation

If changes are made to an existing home in terms of tightening the building envelope and you see changes other than your utility bills going down, pay attention to the details because they may be a warning sign that you have not properly ventilated the home.

Lack of adequate ventilation in a home can result in serious problems.  The more obvious one that appears in obvious places is elevated humidity. If you are sweating the inside of new insulated glass windows in the winter when you didn’t before then your interior humidity has gone too high.  Another warning sign is dirt stripes appearing on the walls in front of the studs.  Musty odors, sweating or condensation, or unusual patterns on your walls could be indications of a ventilation problem.

However, moisture is not the only concern.  You also need to be concerned about gas concentrations in the air because of the dangers associated with them and the build up of volatile organic compounds (VOCs). VOCs are emitted from many products that exist around the home but if you tighten up a home and don’t provide adequate fresh air, they are now being trapped within the home.  Many volatile organic compounds breakdown with exposure to ultraviolet (UV) light outside the home – formaldehyde for example has a half-life of about 14 days – but inside the home UV light is diminished and so has little affect on the concentration of the VOCs. VOCs could be coming off of products which you would never suspect.  For example, some citric acid cleaners that smell like orange can have amazingly high VOC concentrations. Remember, what has changed in the equation is the amount of fresh air that had been there before that helped evacuate these things from the home. The standard furnace filters we employ do not filter out gasses – they filter particles.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (AHRAE) has very specific guidelines on how much fresh air is needed for a healthy environment.  ASHRAE 62.1 references the calculations for commercial buildings and ASHRAE 62.2 is for residential buildings. It is critical to review these guidelines in order to properly ventilate the building envelope especially if you are making changes. When homes are tightened for energy efficiency you must make sure that adequate fresh air ventilation is taken into consideration.  There are many ways to do this that are compliant with the ASHRAE recommendations. And remember, if you find signs of moisture it’s like the canary keeling over in the coal mine.  Heed the warning!

Take a Peek at the Future of Building Codes – International Green Construction Code

It’s about time! The International Green Construction Code (IGCC), subtitled “Safe and Sustainable: By the Book” has just completed the public comment stage.  The draft code is a joint effort of the International Code Council (ICC), the American Institute of Architects (AIA) and ASTM International. The AIA and ASTM have played a vital role in the development of the IGCC.

The AIA presence guarantees a focus on the AIA’s 2030 Carbon Neutrality Goal. ASTM International, which carries a worldwide reputation as a standards developer, strengthens the scientific basis that will drive the Code. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the U.S. Green Building Council (USGBC) and the Illuminating Engineering Society (IES) joined the ICC/AIA/ASTM team in reviewing and commenting on the Code.

This model Code focuses on new and existing commercial buildings and addresses green building design and performance. It creates a baseline for green building by making our basic practices more sustainable while leaving plenty of room for improvement. With many of the lessons learned from the sustainable construction evolution to date being made code, it gives us an opportunity to push the targets of more advanced programs “further down field.” Can you imagine what we may learn or what innovations may come from that?  You can download a copy of the proposed code for review or you can view the video.

We need a green building code.  Up until now, we have only had green standards to define and support the sustainability movement. A standard is just an agreement but a code can be enforced.  The USGBC and NAHB paved the way toward making a solid commitment to build responsibly but creating a Code on a national and international level really changes the game.

Once we have a Green Construction Code the states will need to adopt or amend it to suite their unique requirements. But at least now we have a model Code to put in front of them as a starting point. It couldn’t get here soon enough. 

What are your thoughts as to the pros and cons to an International Green Construction Code?

 

Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation.

Energy Quotient – Look for the ASHRAE Label

ASHRAE labelWe may finally have found a way to qualify and label the energy efficiency of buildings called the Energy Quotient. ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) proposed this standard for reporting the energy consumption of buildings so that consumers can compare the energy use of one building to another.  This is a concept whose time has come in order to make sound decisions about a building either to rent or own.

The Energy Quotient rates, grades and labels building from A+ to F for their efficiencies based on standards ASHRAE created.  This is similar to how Energy Star rates products and gives them an energy consumption rating.

The benefit to this is that once the building industry reports these ratings publicly it’s going to drive building and home owners  to make our buildings more efficient – not only new buildings going forward but retrofitting existing buildings. Just like remodeling a kitchen prior to selling a home to make it more marketable, owners will be making energy efficiency upgrades to improve marketability of all buildings before putting them on the market. This will propel the need to improve existing buildings, which is fantastic.

Initiatives like this provide another level of comparison that benefits the consumer and encourages us to improve what we do as it relates to energy consumption. It’s measurable, it can be reproduced, and it will accelerate our conservation efforts. 

Economically motivated issues are more successful in our culture than mandated ones. Building owners will no longer need a mandate for energy efficiency if they have an economically motivated reason to do it.  It takes energy efficiency efforts away from the programs and puts control back into the free market. This allows the free market to drive the point which it does with this simple label.

Lucas Hamilton

Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications at CertainTeed Corporation.