Counting to zero, one kilowatt at a time

My newest feature article. We’ve already started making the switch to LEDs in our house thanks to this:

Counting to zero, one kilowatt at a time

by Karina Coombs

Residential electric rates have doubled since 1990, with the biggest increases in just the past ten years. In November, citing the rising cost of natural gas (used in the power plants that produce the electricity), National Grid increased its rates by 37%. NStar followed suit earlier this month and raised its rates by 29%.

While many are bracing for larger bills, Energy Task Force member Claude von Roesgen is having a decidedly different experience, thanks to his home’s photovoltaic system. Instead of paying for the electricity he uses, von Roesgen is being paid for the electricity he generates through 36 roof-top solar panels. But after decades of energy conservation awareness, the absence of an electric bill is not his end game. Instead, von Roesgen is focused on getting the building to net zero energy, helping to reduce his carbon emissions.

What is net zero?

A net zero energy building (NZEB) is an energy efficient building that also produces as much annual renewable energy on site as it uses. The building becomes self-sustainable, yet most NZEBs remain on the electrical grid for storage needs. With a vacation home that is already a NZEB, von Roesgen does have some experience in this area. Now he is working on scale. That is because his solar powered tiny houseboat, “TinySol,” at 128 square feet is smaller than the sunroom in his 2,800 square foot home. (See “The little house that makes a big impression,” August 28, 2013.)

A high school student in 1973, von Roesgen vividly remembers the country’s first oil crisis, followed by the second crisis in 1979 during his years in college. Both made a big impression and he became interested in energy conservation, particularly after reading the economist E. F. Schumacher’s, Small is Beautiful: A study of Economics as if People Mattered. “I was sort of tuned into this whole energy thing,” he explains. He began working on energy improvements in his fraternity, charting and posting the amount of natural gas they would use everyday in an effort to encourage people to use less.

Thinking ahead

Energy conservation was not just a passing phase. After college, an architect who was designing and building a passive solar home in Milton hired Von Roesgen to calculate the solar gain from the home’s greenhouse and the number of BTUs needed to heat the building without a mechanical heating system. Following this, he worked with an acoustics company to tackle livability issues in a house located both below the Tobin Bridge and a Logan Airport flight path. Making the building acoustically sound would also make it more energy efficient.

While Carlisle did not pose acoustic challenges for von Roesgen, energy efficiency continued to be a focus when he purchased his home in 1991. While energy prices were low at that time, he was convinced they would climb. “I felt you really wanted to build your house to be more energy efficient [but] in 1991… the notion of net zero seemed like an impossible dream,” he says. “Yes, we can conserve energy, [but] to get to net zero? That doesn’t seem possible really.”

A Garrison Colonial meets the 21st century


Thirty-six panels are distributed between the garage roof and main house roof. (Photo by Carla Schwartz)

According to the Massachusetts Executive Office of Energy and Environmental Affairs, residential and commercial buildings account for 40%  of the energy used in the country. In Massachusetts that percentage climbs to 54, with the largest percentage of energy used for heating the home, followed closely by heating hot water and powering the ever-growing list of appliances and other electronic devices we own.

Built in 1969, von Roesgen’s Garrison Colonial was fairly well insulated to begin with since it used expensive electric resistant heat, but he did additional insulation shortly after he bought it. To further cut costs he did a one-acre land swap with a neighbor, allowing him to pick up enough frontage to bring in a gas line for heating. Von Roesgen also improved his windows, covered up his fireplace and closed up the room above his garage instead of trying to heat extra space.

Going solar

In 2011, he decided it was time to pursue solar energy. Working with a local company, von Roesgen had ten panels placed on the roof of his garage as an experiment into its effectiveness. “I thought, let me just see,” he says. After some tweaking, the system came online in April. It worked so well that eight months later, he had a second array installed on the roof of his house, adding another 26 panels.

When he purchased his arrays nearly four years ago, von Roesgen paid about $6 per watt, but notes that costs have come down and are now closer to $4 per watt and with improved solar panel efficiency. “I was kind of an early adopter in solar. It’s a lot cheaper for a roof mount type of system [now]. Early adopters are necessary to use this technology forward,” von Roesgen explains. “If everybody waits until [this] is perfect, then it’s never going to happen. Somebody has to go out there and buy the system that’s more expensive and less perfect, and I’m raising my hand.”

Net metering and SRECs

Both NStar and National Grid have net metering programs for customers with solar—a program von Roesgen uses and encourages others to think about when planning for a new system. Net metering allows him to receive credits on his utility bill for the energy he puts back into the grid, but also allows him to share those credits with others. The credits could also be applied to a second home that did not have solar, thereby zeroing out its electric bill. Some restrictions apply depending on location and provider however.

He also takes part in the Massachusetts Solar Renewable Energy Certificate (SREC) program. For every megawatt-hour of energy he produces, von Roesgen receives one SREC. The SRECs are then bought and sold at auction, giving him income from his solar panels while also allowing him to use the energy produced. “It offsets a lot of my costs and makes it lucrative for me to actually do it,” he says.

“Not only do I get free electricity. I also get paid money to create electricity. Plus I got the Federal tax credit that lopped 30% off the cost of installing the system.” Von Roesgen explains the system’s inverter will need to be replaced in ten years, but imagines prices for the units will continue to fall. Solar panels have a shelf life of 20+ years, with a marked reduction in capacity after that. The Federal tax credit for solar installation expires at the end of next year. Systems must be installed by December 31, 2016.

Claude von Roesgen with the interior unit of his mini split heat pump. The mini split allows von Roesgen to heat and cool his home without requiring duct work. The exterior compressor unit connects to the interior blower through a conduit in the wall. (Photo by Carla Schwartz)

With his electrical needs met, von Roesgen turned his attention to his heating system. Determined to cut his ties to natural gas, he installed a ductless heat pump that heats the first floor of his house. The compressor sits outside and a blower is mounted on an interior wall – the two connected by a conduit within the wall. The Fujitsu mini split system was installed in 2013 and von Roesgen saw his gas bill cut in half.

“The best electric heat you could do [when the house was built in 1969] was resistant heating. I think heat pumps were available, but they were only considered feasible in the south where the coldest winter temperatures were above freezing. Now you have these cold weather heat pumps that can operate at 5 or -5 degrees Fahrenheit and you really heat your house.” Not only does the heat pump heat the house, but it also acts as an air conditioner and supplies cool air in the warmer months. “If you’re thinking air conditioning you should be thinking heat pump,” adds von Roesgen.

With the success of his heat pump, von Roesgen has decided to replace his gas hot water heater with an electric hybrid hot water heater, which uses heat pump technology. “Heat pump hot water heaters are a great way I think for people to get started because there are a lot more situations where that’s easy to just plug in. It basically has the connections hot and cold and then electricity and it’s the same size as a [traditional] hot water heater.”


Von Roesgen’s ductless mini split heat pump produces both heat and air conditioning for the home’s first floor. (Photo by Carla Schwartz)

Small changes around the house

Not just focusing on large systems, von Roesgen has also made small changes throughout the house that have had a big impact. With the lower cost of LED lights, he recently finished replacing all of his compact fluorescent light (CFL) bulbs, noting the new bulbs turn on instantly, come in different colors or temperatures and use a fraction of the electricity of a CFL. He also upgraded to an energy efficient refrigerator, which saves him 500-kilowatt hours per year, or as he measures it, 2,500 miles of free driving in his electric car—also powered by the solar panels. Von Roesgen has also made lifestyle changes and no longer uses his electric dryer for his clothes and only uses his oven if he is cooking something too large to fit in his energy efficient toaster oven—a habit he picked up from his summer of living in TinySol.

“Electricity becomes precious,” explains von Roesgen of the modifications. “It’s a work in progress. The point is, it’s very doable to use electricity to basically heat your house, do all your entertainment, [plus] do your driving. It’s just really amazing what’s happened [since charting his gas use in college]. Things are completely different and they are going to continue to change.”


To learn more about the Carlisle Energy Task Force, visit:

For a free energy assessment and to learn where you can save money in your home, visit:

To see current renewable energy financial incentives in Massachusetts, visit:

For more information on net metering with NStar, visit:

For National Grid:   ∆

Published by Karina Coombs

Freelance writer

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