Our guest blogger this week is Wes Harding, President of Harding Construction & Sustainable Solutions. He is a college instructor, general contractor, certified green home rater, and energy auditor. He can be reached at www.hardingconstruction.biz

Some homes just blow and other just suck.

After reading your Home Performance Energy Audit Report you found your home was built too tight. Meaning, there are not enough holes in the home and there is not enough fresh air entering.

The goal of any general contractor should be to build the tightest house possible to stop air infiltration and provide the most durable and sustainable product for his or her client. On existing or traditional homes, built before energy code, it is difficult and costly to tighten a home to the point that it is too tight. (I didn’t say it can’t be done.)

The problem with a home built too tight is that now the materials, plants, showers and other things off-gassing and releasing moisture in the air have nowhere to go. This can greatly affect your health and the durability of a home. There are lawsuits currently in place because of the VOC’s found in tight Katrina FEMA trailers that were making the occupants sick. So congratulations on your new home Mr. and Mrs. Smith! I hope you don’t mind breathing toxic levels of formaldehyde and you don’t have a carbon monoxide leak.

Now you may have thought I was bashing green building materials in my earlier posts. Not the case. Recycled countertops, zero VOC products, and materials that don’t off-gas are important, but only part of the solution. They do play a large role in a healthy home, especially if the home is built tight, but still only part of the solution. A whole-house approach has to be taken to understand how the building is operating like a system and that one change in the structure can greatly affect the next.

If your home is built too tight there is a solution. In fact the new California code recently changed to address this (only for new homes). The solution is to control the amount and source of the air before it enters the building. This way it can as be filtered first. This can be done in a variety of ways, but the most common is a Heat Recovery Ventilator (HRV) or Energy Recovery Ventilator (ERV). They attach to your forced air unit and are climate specific in which type should be used. There are stand alone systems that can be installed if you have an existing home and want to do some preventative measures for IAQ.

It is better to have your home blow than suck. No pun intended. Wouldn’t you rather have your house blowing the air out of the small holes from a source you control then sucking the air from the interstitial cavities in which only the bravest contractor will venture.