Blog : There is Green and Then There is GREEN

By Sarah Mahoney | Feb 17, 2015 | in

By Heikki Herb Perry

It may not come as a surprise to some that one of the seacoast-area's greenest homes belongs to Ultra Geothermal, Inc. owner, Melissa Aho. Aho's company takes sustainability nearly as far as it can go, enabling homeowners of new and existing properties the opportunity to heat and cool their homes with clean, renewable — and ultimately affordable — geothermal energy.

Ultra Geothermal, located in Barrington, New Hampshire, has installed more than 750 geothermal systems throughout southern Maine, coastal New Hampshire and northern Massachusetts. Aho's home in Strafford, which can only be described as “over-the-top green," is the finest example of Ultra Geothermal’s sustainability ethos.

While most green builders take such steps as installing Energy Star appliances and high-efficiency gas furnaces, Aho went several steps further. She chose to build her home to the highest National Green Building Standards, which, among several other elements, includes ensuring optimum thermal resistance. She also installed a vertical closed-loop geothermal system and a ground-mounted solar PV 5.6-kilowatt-hour array. And rain barrels collect water for reuse on her flower gardens.

National Green Building Standards
The ICC 700 National Green Building Standard® is a nationally recognizable standard of green building. Of the four threshold levels, Emerald is the highest, and Aho’s home satisfies that category’s strict requirements. Yet Aho asserts it’s possible to build a sustainable and energy efficient home with the same budget as a conventional home build.

“I am not saying that it is simple or easy,” explains Aho. “It does take time to research product development and sustainability of materials being used. However, if you put the effort in, you will have a beautiful home that will pay you and the environment back for decades to come.”

Once completed, Aho's Strafford home received a Home Energy Rating System (HERS) score of 35. The lower the score, the more sustainable a house is considered. An average-built home has a HERS score of 100, which means Aho’s home is nearly three times more efficient.

To fulfill NGBS standards, Aho installed blown-in natural insulation and also insulated the exterior with Structural Insulated Sheathing, which exhibits a high degree of thermal resistance. “When you actually insulate and wrap the whole house with this,” says Aho, “you cut down all the wind barriers, so you don’t have any infiltration.”

Aho used only low or zero-VOC products to paint and stain the home. High-VOC products can contain organic pollutants such as carbon monoxide and radon. Aho also installed a radon venting system under the basement slab to expel other sources of radon, and a rubberized sealant to waterproof the foundation.

Another important green aspect to the home is the 50-year life expectancy on the roof and siding. “Environmentally speaking, the point is that when you have to replace things after 20 years, it takes up landfill space,” says Aho. “So, the idea is not to replace anything on your house for as long as you can.”

Geothermal heating and cooling
Geothermal heating and cooling, also known as a Ground Source Heat Pumps (GSHP), can be a fantastic option to provide both a renewable energy-efficient solution to heating and cooling as well as give valuable points to a home's NGBS rating. And geothermal systems are endorsed by the EPA to be the most efficient, cleanest, and cost-effective heating and cooling systems available.

Although the technology is more expensive upfront, geothermal energy’s down-the-road savings are practically unrivaled. Studies prove geothermal energy to be four to five times as efficient as standard heating oil or propane, making it one of the most long-term cost-efficient energy solutions. Adding to this outstanding efficiency, geothermal systems have an average 30 to 40-year life expectancy.

When federal and state-sponsored tax incentives and interest-free loans are added to the mix, many price and sustainability-conscious consumers opt for a geothermal system.

Aho’s Strafford home is a nicely laid out, single floor living area of 3,000 square feet, featuring four bedrooms, three bathrooms, and an office. It has an expansive unfinished basement, also close to 3,000 square feet, that is heated by radiant in slab. This is done by a water-to-water GSHP system, which, however, does not provide cooling.

Many Ultra customers instead choose a water-to-air GSHP system, which allows air to flow through ducting. The air system provides heat in the winter and cooling in the summer. The main floor of Aho’s house is heated and cooled by such a water-to-air GSHP.

Depending on local geologic conditions, one method of harnessing geothermal energy can prove superior to others. The heat transfer for the GSHP system can be either an open-loop or closed-loop option.

When considering the open loop it is important to look at the water quality of the well because minerals and sediment can cause problems. Another downside to an open-loop system is its regularly required maintenance. Several homeowners with open-loop systems have come to Ultra Geothermal for advice, eventually opting to replace the open-loop systems with closed loops because of maintenance issues. “If you plan to be away from your home for three to four months, for example, you should definitely consider a closed-loop system,” says Aho.

A closed-loop geothermal system can have either a horizontal or vertical configuration. Horizontal closed-loop installations prove most cost-effective for residences, particularly for new construction where sufficient land is available. The pipes are filled with a 25 percent ethyl alcohol-water solution that circulates through the ground into the home’s heat pump system.

For her home, Aho chose the vertical closed-loop system, as its application requires less land space with holes drilled up to 500 feet into the ground and placed only 20 feet apart.

Aho says it's “essential” homeowners determine the correct heat loss of their home and design the exterior loop correctly or it will not be able to heat the home properly.

During a tour of her home, Aho points to pipes running in and out of the utility room, explaining that, unlike the open-loop system, the closed-loop system is “maintenance free. A homeowner does not need to do anything to the closed-loop system.”

She then pauses for a moment to listen to the background sound the various machines produce in the utility room. “This is the geothermal running,” she says. “It’s always like this.”

The room is nearly silent, she notes, “and upstairs, you can’t hear a thing.”

Solar Photovoltaic Cells
“Every day I see the shining sun on my solar PV panels it makes me realize that the energy at our fingertips is amazing. It follows through to the proof on the inverter that shows how much energy the panels are making on a daily basis,” says Aho.

The PV panels provide 50 percent of the household’s electrical needs in a year. “It’s a good match for our geothermal system,” she says.

A 30 percent federal tax credit is valid on both the geothermal system and solar system. And there are different loan programs to obtain financing for these renewable energy upgrades. For example, the state of Massachusetts offers interest-free, uncollateralized loans up to $25,000 to homeowners who install geothermal systems.

Says Aho: “There are a lot of incentives for people to do this.”

Green Alliance members receive a free humidifier with the purchase of a geothermal system. Not a member? Join here!