So you’ve decided to start downsizing your home, and you want to live in Vermont, so now you’re searching for a builder who specializes in high-performance/zero energy home construction. You look online, you search everywhere … and you finally connect with someone who is “certified” in the field, and who promises to do the work for less. You visit the fellow’s office. Displayed on the wall are a few certificates, all of them bearing a gold embossed stamp.
“How did you get certified?” you ask. “Well,” the fellow replies, “I have taken a variety of intensive online courses, most of them followed up with a week in the classroom.” Certified by Internet, you reflect briefly as he keeps talking. I’ve heard of clergy getting ordained via the Internet. Maybe that’s enough to marry and bury, but I can’t afford to bury the $300,000 we have set aside to make this happen.
In this relatively new field of high performance / zero energy home construction, here’s one key phrase to keep in mind: CAVEAT EMPTOR - “Let the buyer beware.”
A certificate doesn’t make an expert. Take, for example, the former airline pilot who was sitting in a classroom with me a number of years back. We were both there to learn how to become energy auditors (energy auditing is a way to identify areas of energy loss in older homes ready for a redo, and also part of checking the performance of new construction).
During the recent economic downturn, the government was paying the way for many people who were looking to reinvent themselves in an attempt to find a new career path in a field where more jobs could be found. Scenarios like this were not uncommon. People with no background in construction (i.e. don’t know the difference between a gable and a gazebo) took a weeklong course and were released into the wilds as “experts in the energy auditing world.” So, just because you see a certification on the side of someone’s truck doesn’t mean they are experts, it means they passed a test. Make sure there is experience behind that certification.
To help you avoid getting scammed by novices, whom my dad calls “New Millennium Builders,” we have created a list of about twenty-five questions to ask any builder claiming to be knowledgeable about high-performance construction techniques. Since the list is long, we’ll run it over several blogs, including this one. You can make this a little more challenging and educational by trying to answer the questions BEFORE consulting the answers and any links that are provided with them. Trust me, this exercise could save you a LOT of money and heartache.
1 How do air barriers differ from vapor barriers?
Air barriers stop air movement; vapor barriers stop vapor movement.
2 In what direction does warm air move?
Warm air rises. Heat always moves to cold – which could be any direction.
3 In what direction does moisture move?
Toward dry areas. https://www.nachi.org/moisture-problems-6.htm
4 What causes mold?
Moisture and a lack of ventilation. http://www.cdc.gov/mold/dampness_facts.htmExplain how and when you “Air Seal” the outside and inside of a house.Special air sealing tapes are applied to exterior joints on the wall sheathing, which is also an air barrier if the correct sheathing is used.
Windows are also taped to the air barrier.
On the interior, air barriers are applied to the surface of the studs that allow moisture (vapor) to move toward dry areas, yet keep a solid air barrier.
5 What is a Thermal Boundary used for?
It identifies where the insulation is located. Ideally, this boundary is as close to the heated space as possible, but sometimes it makes sense to include unfinished areas within the thermal boundary to allow for heating equipment.
6 What is Thermal Bridging?
A thermal bridge is an area of higher heat transfer than the areas around it. For example, in a traditional 2x6 wall, the stud acts as a thermal bridge in the wall construction. The stud is in direct contact with the exterior and interior, while the space between studs (wall bays) are not, thanks to the insulation in the cavity.
7 What is a Thermal Break?
Insulation. In the example above, if a layer of rigid foam were applied to the stud, it would break the high rate of heat transfer compared to the areas around it.