Geothermal system to heat, cool new NoBo home
PV panel powers system, utility bills eliminated for green-minded homeowners
Source: Boulder County Business Report
Author: Christine Weeber
 BOULDER - Two soon-to-be homeowners in a new North Boulder subdivision, NoBo, may have inspired a
greening trend in their new neighborhood.
The home of Catherine Greener, managing director for Domani Sustainability Consulting, and Alan Greenberg, land surveyor with Flatirons Surveying in Boulder, will have a geothermal heating and cooling system powered by grid-tied photovoltaic (PV) panels. With these systems in place, the owners expect to have no monthly
expenses for heating and cooling their 3,300-square-foot home.
When Mary and Tim Coonce, owners of Porchfront Homes by Paragon Builders, the builders of NoBo, told another couple about the geothermal and PV systems, the couple decided to follow suit and install these systems in their new home in the subdivision. Another couple also is interested in having a PV system.
This is the kind of impact Greener and Greenberg were hoping to have. "We had a vision of trying to make the type of home that is typically being constructed across the country be as sustainable as possible, and to demonstrate what any homebuilder could do," Greener said. "Porchfront Homes was very open to working
with us to fulfill our vision." Despite the challenges presented by customizing, the Coonces are excited about the possibilities. "We use a
ton of recycled materials, and we're going more high-efficiency with our furnaces," Mary Coonce said. "But for
people to make that big leap into geothermal and the big leap into solar, that's a big step. The goal is to make
those things more affordable for people in a good old, regular subdivision."
For Greener and Greenberg, greening a stock home was one way to have a more sustainable house at a price
that fit their budget. They purchased their new home for $500,000, and the additional cost for the geothermal
and PV systems was close to $60,000. But the extra upfront costs will pay off in about 10 years, Greenberg
said.
"You can afford to build the house, but can you afford to run the house?" he added. With all of the home's
heating and cooling needs met by the geothermal and PV systems, "our costs will be fixed, which also
improves the resale value of the home," Greenberg said.
These systems also benefit the environment. "We won't be producing the carbon dioxide that a regular house
does, so we're minimizing our carbon footprint," Greenberg said. The geothermal heating and cooling industry
estimates that installing one system is equivalent to taking two cars off the road or planting 750 trees.
Geothermal systems work by exploiting the year-round temperature of the ground, which is about 52 degrees
in Boulder County. In winter, water circulates through pipes 150 to 200 feet deep and absorbs heat from the
ground. Once inside the house a heat pump unit transfers the heat from the water to a gas, and compresses
the gas until it reaches 160 degrees. Air blows across hot gas-filled coils to heat the house through a typical
duct system. In summer the system is reversed, so warm air from the house is carried through the system
and absorbed into the ground.
The initial investment in the PV system was significantly reduced by recent rebates from Xcel Energy spurred
by Amendment 37. The amendment called for energy companies to acquire a certain percentage of Colorado's
electricity from renewable energy sources. Greenberg estimates the retail cost of their 5-kilowatt PV system,
which was designed and will be installed by Boulder-based Namaste Solar Electric Inc., at $40,000. The actual
cost to them will be closer to $16,000, he said.
Though minimal compared to the rebates, federal tax credits can be taken for both the PV and geothermal
systems. The basic geothermal system is approximately $18,000 compared to an estimated $7,500 for a high-
efficiency furnace and air-conditioning system, said David Petroy, vice president of Blue Sky Energy Solutions
Inc., the Boulder-based company that designed the geothermal system on the Greener-Greenberg home. The
federal tax credits are probably a few hundred dollars for the geothermal system, Petroy said, but he argues
that the system is really a kind of insurance. "You are much less dependent on the utilities for your energy
use," he said.
Blue Sky Energy Solutions Inc. works in partnership with Valley Geothermal LLC in Longmont to design and
install the geothermal systems. Petroy said they install 40 to 50 systems a year in new homes and as retrofits
on existing homes.
Other green features of the 3-bedroom, 21/2-bath home include airtight walls insulated with Icynene, an
environmentally friendly blown-in foam insulation, no-VOC paint, bamboo flooring and dual-flush toilets to
conserve water. Homes in the NoBo subdivision currently sell for between $599,000 and $650,000, although eight of the
homes are earmarked as permanently affordable. These sell for between $166,000 and $210,000. NoBo will
have a total of 44 single-family homes and, hopefully, an additional 22 town homes. Nine homes are
completed and 15 are under construction or permit.
"The rebates and tax credits, education, and the fact that we are making it available for people are definitely
having an impact," Mary Coonce said. "I'm real happy that people who are buying from us are starting to get
excited about (solar and geothermal). And you know how that happens- it transmits," she said. "You are
excited about it and other people get excited and say, 'Hey, I can do that.' "
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