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Green Building Blog

Blog Review: Thriving on Low Carbon

Blogging from his new home on Martha’s Vineyard, energy guru Marc Rosenbaum writes about deep energy retrofits, the Passivhaus standard, and reducing his carbon footprint

Image 1 of 2
Work in progress: Energy consultant Marc Rosenbaum has taken up residence in a cohousing community on Martha's Vineyard, Mass., and writes about his experiences in a new blog.
Image Credit: Image #1: Marc Rosenbaum
Work in progress: Energy consultant Marc Rosenbaum has taken up residence in a cohousing community on Martha's Vineyard, Mass., and writes about his experiences in a new blog.
Image Credit: Image #1: Marc Rosenbaum
Marc Rosenbaum in one of his favorite T-shirts. The T-shirt reads, "Talk Nerdy to Me."
Image Credit: Image #2: Martin Holladay

Marc Rosenbaum is a well-known energy consultant who for 25 years lived in a house he called Nerdwood in Meriden, NH. It was heated mostly by wood and the sun. Rosenbaum’s company, Energysmiths, took on a variety of consulting jobs, including some for South Mountain Company on Martha’s Vineyard, which developed a cohousing community there called Island Cohousing.

Then, last June, Rosenbaum left New Hampshire and moved with his companion Jill and their dog to a rented house at Island Cohousing and went to work for South Mountain. They have since purchased the house and settled into the 16-house community, which describes itself as an “ongoing experiment in collaborative living.”

This spring, Rosenbaum also started a blog called Thriving on Low Carbon that talks about his experiences in his new home.

“As most new homeowners know, every direction you look, you can imagine a way to spend money,” Rosenbaum writes in an early blog entry. “Living as we now do in a maritime location, I can tell you that at least a house is not as bad as a boat, which I learned is an acronym for Bust Out Another Thousand$.”

Still, Rosenbaum is finding plenty to do. The houses in his community were more carefully built than the average house (Rosenbaum, in fact, consulted on the specs), but there were a number of improvements that could be made. Rosenbaum hooked up his trusty blower door, got out his theatrical fog machine and went to work finding and fixing air leaks. And he removed the oil-fired boiler that had been providing hot water and heat and replaced it with a ductless minisplit heat pump. No doubt there’s a lot more to come.

The subtitle for Rosenbaum’s blog is “How I’m thinking about our house, transportation, food and waste, to minimize environmental impact, while improving quality of life and having fun.”

That seems about right. There is some geeky stuff here, but nothing off-putting or overly technical. Instead, it’s a readable mix of technical information and observations of a more personal nature. The tone is open, friendly and informative.

Here are a few excerpts:

On teaching and lineage

“In Buddhism, lineage is the line of teachers who have passed the Dharma from teacher to student in a recurring and unbroken cycle – the student becomes the teacher of the next student… Lineage is vertical and successional. In contrast, community is lateral and evolving. To continue with the Buddhist analogy, the word is sangha. Sangha is a mutually supportive community composed of members with a shared vision and set of values. The environmental/solar/energy efficient building community has been my sangha for over thirty years. I’ve made a number of my closest friends from this community, and I’ve learned almost all I know about the work I do from it.”

My carbon footprint

“A few years ago, probably after reading Jim Merkel’s book Radical Simplicity, I worked through one of the carbon calculators. My carbon footprint was different than most Americans, because I lived in a house that I designed to run primarily off of renewable energy. It was eye-opening to see that four domestic airplane flights annually, three of them in the eastern US, and one to the west coast, were half my carbon footprint. Forty percent of the total was driving a car – 18-20,000 miles a year, even though it was a 40 mpg car. Over two-thirds of this was work-related, so I rationalized it, but I actually don’t like driving and therefore had a double motivation to reduce auto miles.”

The problem with payback

“At some point in every workshop or seminar I teach, whether it’s on Zero Net Energy Homes, or Deep Energy Retrofits, or Passive House principles, someone stands up and makes an impassioned speech about how all this is well and good but what’s the payback?…The quickest response I have is, if you predict the future price of energy over the lifespan of these improvements, I’ll tell you the payback. My habit when pushed to actually do some financial analysis is to present it in the form of scenario planning – I’ll often select three rates of energy inflation and do the calcs showing the Net Present Value of the investment in each inflation scenario. The longer you project it out, the more dramatic are the differences. The usual result of this exercise is that those who are the decision makers begin to act from a position of risk avoidance, because the highest inflation rates in fuel costs get scary.”

Why heating with oil had to go

“If you arrived at this blog, you don’t need to be convinced that it’s a worthy goal to burn less fossil fuels. That’s not the only reason to want the oil system gone, though. Have you ever been in a house where there has been a spill of fuel oil? It soaks into the ground below. You can smell it for decades. The cost of clean up can exceed the value of the house.”

About heating with biomass

“What about biomass? Advocates often say that biomass is carbon neutral, because a tree absorbs carbon as it grows, and as it decays, that carbon is released. By burning biomass, we’re just hastening the release. I don’t think it’s quite that simple. Pellets, especially if they are made from wood chips (they used to be wood waste, less so today) need to have the wood chipped, then dried, then ground up and pressed into pellets. There is some fractional PE factor there. Firewood cut on your own place with a handsaw has a pretty low [primary energy] factor!”

2 Comments

  1. Miki Cook | | #1

    Carbon Calculator for Home Construction
    anyone have any experience using the Athena Institute Impact Estimator? I'd like to model alternative construction scenarios to see how much impact each has on reducing the carbon footprint of design elements, material and system choices. Need some help navigating the tool.

  2. User avater GBA Editor
    Martin Holladay | | #2

    Response to Miki Cook
    Miki,
    The best place to post your question is on GBA's Q&A page:
    http://www.greenbuildingadvisor.com/qa

    That way you are more likely to get a variety of answers from several GBA readers.

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