Going back to the “net-zero” thread and this house in particular.

 

http://www.greenbuildingadvisor.com/homes/energy-comes-sun-wind-and-earth-vermont-leed-platinum-home

 

and the follow up

 

http://www.greenbuildingadvisor.com/blogs/dept/green-building-news/vermont-house-wins-10000-net-zero-energy-prize

 

 

The more I read the more questions I had.

 

Let’s go to the $40,500.00 windmill first. The focus seems to be on the fact that the windmill produced more power than the house used over the year. Apparently no one has bothered to do the math.

 

It’s a 10 KW windmill so it has the potential to produce 10 KW’s per hour. There are 8760 hours per year so potentially the wind mill could produce 87,600 Kwh’s annually. According to the story it produced  6,094 Kwh’s or an efficiency of about 7%.

 

Even though the owners managed a $12,500.00 subsidy and only had to pay $28,000  someone still has to pay the  cost of $40,500.00.  So let’s prorate the cost over a projected 20 year lifespan. Assuming that they rolled the windmill into their mortgage at 4% interest the monthly payment is $245.42

 

$245.42 times 12 months equals $2945.04. Divide  that by the 6,094 Kwh’s it actually produced means that they really paid $.483 a Kwh for their power or about 4X the national average. This  figure leaves out any maintenance at all which is not realistic.

 

So far from being “net-zero” in fact the house, based on the hidden energy costs and its super insulated construction, is no better than a typical home. The fact  that they  moved the carbon emissions  geographically to where the windmill was made and in time by hiding their costs in a 20 year loan changes the physics not a bit.

 

They had a net electric gain of 192 Kwh. We’ll assume they sold that back to the utility at retail at 12 cents a Kwh. That’s $24.00 a year. That’s how much they really saved on their $40,500 investment in green energy. In just 1,647 years it will produce enough energy to pay for itself.  

 

“The wind turbine, 400 feet from the house, is barely audible.”

 

Of course it’s barely audible, at 7% efficiency  it’s only turning 1 hour 45 minutes a day! But imagine this house had been built by an average American rather than a wealthy architect, the windmill would either be right outside the back door or close enough to the neighbors to drive them nuts. How many people have the option of putting the windmill 400’ away?

 

And this.

 

“they hired Andy Shapiro, an energy consultant, to model a best-case scenario, including orientation,”

 

Site orientation is a function of your wealth and ability to buy a large enough piece of land that you can site your house wherever you like and in most cases is anything but energy efficient. Site orientation is more a function of  country living since in urban and suburban settings you buy a platted lot and take whatever orientation you get.

 

I’d guess the smallest parcel anyone would buy that would allow for the house to be oriented in any particular direction would be about 5 acres. Of course  5 acre parcels are not  cheap and  also come with the requirement for large cleared areas and usually a long driveway to get to the house, neither of which are exactly energy efficient.  These  country houses also require much more energy consumption to deliver materials and for the construction crews to get to the jobs every day.

 

 

“Net electrical gain: 192 kWh”  Didn’t they use 175 Kwh of wood?  How did the wood get to their fireplace?  Didn’t someone have to drive a truck to the tree, cut it down, buck it and haul it to the house to be burned? How much energy did that take?

 

 

Seems to me that rather than win “Green” energy awards  they should have been penalized for their silly  excesses.  I think it also speaks volumes to the entire “Green” and “Net-Zero” community and their apparent  total lack of any kind of skepticism or math skills. It’s also telling that so many of these homes are built  and touted by those in the “Green” industry, not ordinary homeowners. How many of these insiders are using these homes as marketing tools and writing off “Green” improvements as business expenses?