Friday, June 05, 2015

More on the ecology of "tiny houses"

Here is a post from advocates indicating that they're getting about 8-10mpg towing their 10,000 lb home with a Powerstroke F250.  But actually, given that the price of diesel fuel in Oregon is (like here) edging below $3/gallon, they've actually gotten about 8.5mpg or worse.  That's about what my aunt gets towing her 30 foot travel trailer (she works at renaissance fairs, that's how it goes) with a one ton dually with.....big block gas engine.  

But that said, that's not quite fair to the "environmentally sound" tiny home, because a 30 foot travel trailer with slide-outs has over 250 square feet of living space.  The Tumbleweed Cypress 20 has only 144.  Let's choose a better comparison.

My choice?  The Airstream Flying Cloud 19' again, of course, which has almost precisely this floor space, a reputation for 50 year durability, and again about the same price as the Tumbleweed.  It weighs 3852 lbs, about the same weight as the twin axle U-Haul trailer I towed with a ton of wood with my 1997 GMC Sierra K1500.  My mileage from Chicagoland to the Twin Cities?  15, with a gas engine. 

Let's translate this into carbon impact.  The Airstream has about a ton more metal than the Tumbleweed, but towing it with an F250 adds about 1400 lbs to the tow vehicle weight vs. my Sierra or Acadia.  So if 4 lbs of carbon dioxide are emitted for each pound of metal, the "vehicle plus camper" part of the Airstream releases about 2400 lbs more carbon dioxide than does the Tumbleweed.

On the flip side, pulling the Airstream 15000 miles would require only 1000 gallons of fuel for my vehicles, while towing the Tumbleweed appears to have required 2100 gallons of diesel--an increase of about 6000 lbs of carbon or 22,000 lbs.

In other words, these "tiny" houses, if towed, are a serious environmental problem, not a benefit, and we haven't even quantified the environmental impact of the materials used in the home, or the mileage I could have gotten with my SUV or an appropriate diesel.  Cool, yes.  Beautiful, often.  Environmentally sound? Only if you never move it, and then why bother with the trailer?

Once again, it seems that environmentalists are all too often "people who cannot do math", and along those lines, the amateur accountant in me notes that they haven't depreciated their truck or house to calculate the entire cost of the home.  You can get a lot of home for just the figure they forgot to include.  "Oops".

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