Archive for Green Building

How Not to Publicize Net Zero Homes

I received this photo as part of a press release from Nexus Energyhomes,  which builds net zero homes, and is doing a groundbreaking on a community near Charleston, NC which will combine solar and geothermal to produce zero energy homes.

All well and good, but did they really have to go with a rendering of a home where both the house and a tree will be shading the solar panels on the garage for several hours in the morning?

Perhaps the graphic designers should spend a little more time talking to the architects.

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The ERoEI of Energy Efficiency

In previous articles, I’ve often claimed that the Energy Return on Energy Invested (ERoEI) for energy efficiency measures is much higher than the ERoEI for Renewable or fossil energy generation. This was based on the logic that a high ERoEI is needed to sustain the high financial returns from energy efficiency. Unfortunately, there are few studies of the energy return on energy efficiency, so most of my evidence was anecdotal.

No longer. I was just reading the 2009 Annual report for Green Building company PFB Corporation (PFBOF.PK.) PFB manufactures SIPS (Structural Insulated Panels) and ICFs (Insulated Concrete Forms) and in their sustainability report, they found that the energy saved by their insulation over 50 years would be approximately 130 times the energy used in its manufacture (see chart.)

Since ERoEI is a flawed measure, I also calculated the Energy Internal Rate of Return (EIRR), using both 25 year and 50 year lifespans… they worked out to be 262% and 264%, respectively. For comparison, the highest EIRR I’ve found for a energy generation technology is 205% for wood cofiring. The EIRR for a wind turbine is around 84%, and a combined cycle natural gas plant has an EIRR about 164%.

In otherwords, insulation is a slam-dunk when it comes to energy economics. That’s no surprise, but it’s nice to have some numbers, so we have a better idea of just how good a slam dunk it is.

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Greenwashing at KB Home

Poor attic insulation melts snow
I took this picture on February 7, 2010, in Denver’s Stapleton New Urbanist development in Denver.  Most of the houses in Stapleton are EnergyStar qualified, but this picture tells a story about some that aren’t.  The blue house in the background was built in 2009 by Wonderland Homes.  The tan house in the foreground is a KB Home built in 2008. 

Note how the still-falling snow is melting on the north-facing roof of the tan KB Home, but not on the similarly oriented roof of the blue Wonderland home.  Also note that clear lines of unmelted snow where the roof trusses add an extra layer of insulation between the attic and the roof.  This is a clear sign that the KB Home (NYSE:KBH) lacks sufficient attic insulation, and enough heat is escaping from inside the house to the attic to melt the snow on the roof as quickly as it is falling.  Nor was it just this one house… all the houses I saw that were built by KB showed signs of snow melting on the roof, while all the houses I saw built by other builders (New Town Builders, Wonderland, and McStain) showed no signs of melting.  Many were built in 2007, before either of the homes in the photo.

I was shocked.  The Stapleton website proudly proclaims “Since 2006, every Stapleton builder had been an EnergyStar partner.” I’d taken this to mean that every home built in Stapleton since 2006 was an EnergyStar home… an assumption I’m sure Forest City (NYSE:FCE-A) and KB Home would love us to assume.  Instead, I have to assume it means that KB builds some EnergyStar homes, somewhere.

KB’s web page for their Coach Series homes in Stapleton displays the EnergyStar logo in two locations.  One logo appears with the text “An EnergyStar qualified neighborhood” (emphasis mine) and the other is in a box that says “Save 30-45% on your utility bills with a new KB home compared to a home built as recently as the 1990s.”  The implication is clearly that the Coach series homes are EnergyStar homes, but my photo shows clear evidence that they are not.  (Ironically, the New Town and Wonderland websites display the EnergyStar logo much less prominently.)

From page 19 of KB Home’s2009 Sustainability Report [pdf]: We have a long history of building ENERGY STAR qualified homes. The percentage of our homes that are built to this exacting standard has grown from 1% of our home deliveries in 2001, the year we began working with ENERGY STAR for Homes, to 37% in 2008. One-third of our divisions built every one of their new homes to this standard in 2008, and only one of our divisions did not build at least some ENERGY STAR qualified homes.

I’m underwhelmed.  First, EnergyStar is not an “exacting standard.”  An EnergyStar home must save at least 15% of the energy used by a standard code-built home.  According to a 2008 National Renewable Energy Laboratory study [pdf p.14], “for a 2,000-gsf house built to achieve 30% energy savings relative to standard practice, a homeowner can save $512 a year more on his or her energy bills than the extra cost of the slightly larger mortgage.”  In other words, this “exacting standard” leaves a lot of money on the table, even when the additional cost (and mortgage) is accounted for.

Further, 37% EnergyStar qualified is better than your average homebuilder… but your average homebuilder does not plaster their website with the EnergyStar logo. 

I wonder if the owner of the tan house (or any of the many other KB Homes I saw with melting snow on the roofs) think they are living in EnergyStar homes?

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