I was reading the article "Solving the Uplift Puzzle" in your
July/August 2007 issue, and I could not agree more [with the
new approaches]. We are a residential framing contractor in
Jacksonville, Fla. We frame approximately 1,200 houses a year
in northeastern Florida. Recently, we partnered with a lumber
company, Panel Tek, and a local residential engineer to put
together a very aggressive style of engineering that has
eliminated 90% of the steel connectors in the houses we frame.
We've been incorporating this style of engineering in our
framing for about a year now and have found that the savings to
the builder, and ultimately the consumer, are substantial. The
combined use of uplift and shear in the wall sheathing panels
is the basic ingredient to this new style of engineering.
Vice President of Construction, S.A. Robinson
I think that this magazine is highly worthwhile. In the last
issue (July/August 2007), however, there is a slight yet very
important oversight in the article "Air Leaks: Hidden Moisture
Movers." Depressurization due to improper air movement can, and
often does, cause backdrafting of combustion appliances, which
introduces carbon monoxide (CO) into the building. The lack of
understanding of this issue ranges from improper CO detector
placement (remember CO is lighter than air) to tightening a
house without calculating required air exchanges. We strongly
support building science and looking at what it takes to build
a whole, interconnected unit. It would be nice to see a
follow-up article that includes the testing guidelines from the
Building Performance Institute.
Bonded Building & Engineering
Oyster Bay, N.Y.
Information about the Building Performance Institute's
technical standards can be found online at
No Free Lunch
Aaron Hoover's article on so-called "zero energy" homes
("Extreme Green," Breakline, July/August 2007) was well written
and informative. Advancing the energy efficiency of homes
should be a goal of builders throughout the United States and
particularly in the South and South Central regions, where
household energy consumption leads the nation. But I'm
disappointed that your magazine continues to promote the "zero
energy" fallacy. This term suggests a kind of perpetual motion
machine that's not really possible. While the technology exists
for homes to generate their own power, the net result will
never be zero energy. Even the NAHB Research Center, in its
wildly optimistic assessment of the potential impact of
zero-energy homes, concludes that only a partial reduction of
energy usage is deemed possible:
By 2050, ZEH with a tax incentive for solar technologies can
reduce the energy consumption of all single-family homes by
19%, while over the same time, the stock of single-family homes
increases by 39%.
Homes will always require more energy to operate than they can
feasibly produce. To suggest otherwise sets unrealistic
The often cited definition of a zero-energy home is one
that can return as much energy to the utility as it takes on an
annual basis. However, net savings are tabulated in different
ways. Some argue, as you do, that the net energy provided on
site should equate to 100% savings on total energy used, while
others factor in the total efficiency of the home to arrive at
a net savings compared to the usage of a conventional home.
Still others claim that if the home runs on energy from
renewable sources, regardless of where this energy is produced,
it qualifies as net zero energy.
It's worth noting that the report you cite from the NAHB
Research Center is advancing a claim about the energy usage "of
all single homes" (our emphasis), not of ZEH homes only.
However great the reduction of reputed ZEH homes, even these
cannot account for the energy usage in all none-ZEH
Your point is still well taken. Regardless of how the savings
are accounted for, the more precise term now preferred by the
U.S. DOE's Building America team is "near zero energy" (which
is also used by Mr. Hoover in his article). This would have
been the better term to use throughout.