Posts Tagged ‘net zero’

Main Eco Homes Bring Traditional Look to Net Zero Buildings

Tuesday, December 18th, 2012

Maine Eco Homes Net Zero Home Sweden Maine

“Net zero is the way we all need to go” says Justin McIver, summing up the building philosophy and value proposition of his Main Eco Homes (MEH).

30-year-old McIver is a Fryeburg-native and the son of an electrician, so trades are a way of life for him and his family. But after studying environmental issues as part of his business curriculum at Colby Sawyer College in New London, NH, McIver realized that energy efficiency would be critical to the future of the building trade – and the future of the planet.

“There’s just no room for the status quo anymore,” McIver says, “Conventional building saves a little bit of money in the short-term, but long-term is a terrible proposition for both the homeowner and the environment. Our homes save you money from day one. The average Maine home spends $300 a month on heat and electricity, ours costs $0. Rolled into a mortgage, going net zero is a cash flow positive investment.”

Traditional Look, Net Zero Performance

For McIver’s MEH, it was important that premium performance not affect building aesthetics. His first custom model home, built in Sweden, is a 2,000 sq. ft. traditional craftsman building with views of Mt. Washington. “We aimed to create a classic American look, not a space age modern look,” says McIver, “Apart from the solar panels on the roof there’s not much about it that draws attention to itself.”

And solar panels it has – the 39 solar panels on the roof of the MEH model resale home will produce roughly 12,000 kWh each year, enough to power all of the ‘plug’ loads in the home as well as a mini-split air source heat pump heating system. The home features a suite of Energy Star appliances including range, dryer, and refrigerator. An efficient electric water tank will provide hot water for dishes, laundry, showers, etc.

A Collaborative Proces

ReVision frequently works with builders like McIver, as well as architects, engineers, and other building professionals throughout the early stages of a project to ensure that goals for solar integration can be achieved.

For example, a home’s overall orientation is critical, and so is ensuring there is adequate south-facing roofspace to accommodate solar panels. ReVision engineers – such as Geoff Sparrow, who worked closely with McIver – can model the expected performance of a solar array and compare it to the home’s expected energy consumption using advanced software such as PolySun. By integrating discussions of solar early in the process, the solar project can be installed more economically and effectively.

For his part, McIver is more than satisfied. “Geoff was a great resource who went above and beyond to ensure we got the information we needed and that everything moved along smoothly. So far the solar has been performing trouble-free and meeting or exceeding our expectations. We look forward to doing more.”

Facing a Warmer Future

On a walkthrough of the home with a group of Fryeburg high school students, McIver brought global issues down to the local. Quoted in the Conway Daily Sun, he says:

Due to climate change, [more extreme storms] are happening now. If you think it doesn’t impact you, it does. And the changes that your generation makes will make a difference. It’s incumbent on all of us to do the little things, too. When you don’t turn off the lights when you leave a room, for instance, not only does it cost more money, it also puts more carbon dioxide into the atmosphere … [But] it’s becoming more practical to build [net zero] homes… By building these, I am reducing carbon emissions and fossil fuels that harm our environment and which contribute to greenhouse gases. My mission is to become energy independent of fossil fuels.

Driven by an environmental as well as an economic mission, McIver is ambitious. His next project is to build a complete energy efficient community in Raymond, and future plans include proposing a solar farm to the town of Bridgton.

“The time for doing this is now,” McIver says, “When you look at the numbers, long-term, it just makes sense. When you look at the environment… you realize that it’s the way we have to go. I’ve read that 70% of people buy for efficiency and 30% buy for the environment. Now, you can do both. It’s a win-win for everyone.”

Learn more about the net-zero home at Maine Eco Homes. The home is currently listed with RE/MAX at the Lake Real Estate of Bridgton, and tours are offered on an ongoing basis. You can also see a tour that was recorded online at:

Energy Efficiency Made Doable: Plymouth Village Water and Sewer District Does Net Zero Retrofit

Tuesday, October 9th, 2012

Plymouth NH Wastewater/Sewer District SolarReliance on fossil fuels hits towns and local government in the pocket book just as much as it does homeowners and businesses. In times of tight budgets on every level of government, saving money thanks to efficiency makes good fiscal as well as environmental sense. Moreover, town buildings can serve as a model for their communities. Thinking “big” on the local level and that can cause ripples outward into the community.

This kind of thinking is what drove Steve Kahl and Bob Reals of the Plymouth (NH) Energy Commission to submit four DOE grants for projects at their local water and sewer districts (Plymouth Village Water and Sewer District-PVWSD). Their vision? Take a conventional double-wide trailer used for office space and turn it into an energy efficient, net-zero building.

“The idea came from a basic concept: let’s demonstrate what is possible,” says Steven Kahl, architect of the grants, “Unlike the town hall, these administrative offices are housed in a double-wide trailer, which we thought more people could relate to. We wanted to make the point that any building can benefit from efficiency improvements. We had plenty of naysayers that were sure energy efficiency and renewable energy doesn’t work, so we wanted to show, not tell, a different story.”

Making It Happen

schematic of net zero retrofitThe successful funding of two DOE grants, plus local utility and state rebates made the project possible. One proposal was for the efficiency and super-insulation part of the project, where the fairly conventional building benefited from 20″ of cellulouse and 2″ of spray foam insulation in the ceiling, raising it to R80, 4″ of foam and 6″ of fiberglass batts in the walls, raising them to R-43, as well as 5″ of foam insulation in the basement and improvements to doors and windows.

Another grant funded renewable energy inputs: solar photovoltaic systems on the town library, elementary school, and PVWSD administrative office. The 9.4kw grid-tied solar electric system will generate roughly 11,900 kWh annually, providing for all of the electric needs of the space – including electric heat! The choice to maintain electric heat, and offset it with clean solar power, means that the building generates all of its own energy. In other words, it is ‘net zero.’

The Results

solar pv net zero resultsAccording to Kahl, the project went smoothly and results have been impressive.  “I had solar installed on my home, too, and I can say with this one ReVision came with their usual ultra professional design and installation.  The solar array started banking electricity for winter use as of this March, and has so far generated a surplus of almost 4,000 kWh.”

Of course, it’s not just about the numbers – a well insulated building feels better, too.  “The occupants report greatly increased comfort after the retrofit due,” Kahl says, “The project resulted in a 70% reduction in air infiltration, resulting in an indoor environment that is considerably more consistently heated and comfortable.”

This demonstration project was funded by an ARRA grant, NH Office of Energy and Planning, Department of Energy, the NH Electric Coop and the Plymouth Village Water and Sewer District.  All of the technologies used in the project are cost-effective for homeowners, who in NH can now benefit from a recently revived state rebate program.

Heat Pump and Rooftop Solar Puts Northeast Radiant on Path to Net Zero

Thursday, June 21st, 2012
Solar Powered Air Source Heat Pump - Gardiner, Maine

The 14.4kw grid tied photovoltaic array on NRT’s Gardiner offices makes their operations close to net zero!

The rising cost of oil and gas has spurred Mainers’ interest in heating alternatives. A new generation of heat pump technology and falling costs of solar electric modules have combined for a vision that many would not have believed feasible: affordable electric heat offset entirely by solar power.

Leading this charge is Northeast Radiant Technologies (NRT), who recently installed a 14.4kw solar electric array on the open south-facing roof of their Gardiner, Maine offices, alongside a Daikin Altherma air source heat pump.

Being full service heating system design professionals, NRT knew intimately the full range of heating options available. Their choice to go with solar and an air-source heat pump was based on a commitment to environmental responsibility and an exciting vision: a heating system powered solely by the sun.

The Power in Going Solar

“The ability to go Net-Zero with a PV array for a small business like ours was really attractive,” says NRT Co-founder Rob Brown, “With our competitive grant, our time to pay back the system cost is less than 7 years and even with just the base tax credit it’s about 13. We felt if we could really tread that lightly on the earth for that kind of a price it was well worth it to us. And of course, in the end it’s an economic winner as well.”

NRT was able to take advantage of a suite of rebates including a $2,000 Maine state rebate (recently increased to $4,000 for businesses), a 30% Federal Investment Tax Credit, Accelerated Depreciation Benefits, and an Efficiency Maine grant.

Unlike a choice to invest in fossil fuels, NRT knows that in the future their cost of energy will never increase. The solar electric system will produce a little over 18,000 kWh of power a year – a savings of close to $3,000 annually at today’s prices.

The solar electric panels are long-lived, with an expected life span of 30+ years, and contain no moving parts. Whenever the sun is out, clean electricity is generated and either used immediately in NRT’s offices, or exported to the grid.

A Wood Shed That Stacks Itself

The heart of NRT’s heating/cooling is the Daikin Altherma, an air source heat pump that extracts heat from the outside air and transfers it inside through refrigerant piping to supply heating.

Unlike traditional resistive electric heat, electricity is used to move air, rather than heat it, which makes it 2-3 more efficient than resistive electric heat (this is called a COP of 2-3). The system can extract heat from ambient air as low as -4°F! In addition to heating the building, the Altherma also provides cooling – all without the well-drilling or excavation requirements of a geothermal system.

Altherma heat pump diagram
Diagram of the “split type” Altherma heat pump. An outdoor compressor unit moves heat or cool from the outside, passes it through a refrigerant line, and distributes it via a hydronic system.

The cooling is a significant aspect for NRT, who is a “peak load contributor” during the warm summer months, which, conveniently, is when their solar electric system will be at peak production. During the times NRT’s system produces more electricity than is consumed in their building, they will bank power with the utility company in the form of a credit. These credits can be used to offset electricity costs in the winter when their electricity will go towards their heating load. As one ReVision staffer remarked, a solar-powered heating system is kind of like a wood shed that stacks itself.

Space Heating Design Makes a Difference

Even with the solar photovoltaic project and Daikin Altherma, NRT’s offices wouldn’t be near reaching their net-zero goal without an elegant radiant distribution design (their specialty, of course!)

NRT’s building is very tight, and unlike most homes in Maine, their cooling loads are equal to their heating loads. For optimal comfort year round, they use three different systems: a hyper-efficient UltimateAir ERV (50 watts), a chilled water coil to dehumidify (25 watts), and a radiant distribution pump (25 watts). That’s 100 watts of total distribution consumption, in contrast to the hundred of watts used in most ducted systems.

This combination of efficiency and renewable energy generation makes for a perfect situation for NRT: “We love watching the array generate juice,” Brown says, “It’s made limiting our power usage here to reach the net zero goal a fun game we all like to play. We really feel like we’re making a difference.”

Full disclosure: NRT and ReVision have collaborated on dozens of space heating projects over the years, so we took a special delight working on this project, as did NRT. Rob adds, “We love working with ReVision. You just can’t beat working with other professionals who not only believe in what they doing but who can do their jobs with the utmost professionalism and technical acumen. Having your staff here at our site was a blast.”

Feeling’s mutual, Rob. Enjoy that sunshine!

New Home Harnesses PV to Power Geothermal System

Thursday, December 22nd, 2011
Solar Powered Geothermal System - Kennebunkport Maine Solar

This home in Kennebunkport, ME is almost 100% solar powered, using solar generation to power a geothermal heat pump system.

George Longstreth’s dreams of a solar home started nearly a decade ago, when he had a crude off-grid system installed for a seasonal beach cottage on Baker’s Island, MA. “It was basic, just four small panels, but it was enough to run the microwave for a few minutes or brew a pot of coffee. It got me thinking about how this technology could be applied for a normal home.”

This thinking process lead him to Yestermorrow Design/Build School in Warren, Vermont, where he learned the basics of green building and passive solar design. Then, he scoured Northern New England for an ideal location to build his solar home, a search that took him from Southeast New Hampshire to Portland, Maine, before he found the property of his dreams in Kennebunkport.

“It was a beautiful property with good access to solar south,” he says, “That’s when I started assembling the best team of local contractors to make the project happen.”

His search for a solar contractor brought him in contact with a number of companies in Southern Maine, but he chose ReVision Energy because “you knew what you were doing.” After a preliminary meeting with engineer Geoff Sparrow, ReVision worked with George and his architect, Hans Warner, to design a 8.28kw solar electric system to be mounted on the home’s south-facing roof along with 2 flat plate solar hot water collectors for his domestic hot water supply.

Solar PV + Geothermal = Synergy

Solar is just one part of the renewable energy systems in Longstreth’s new home. George also contacted Dr. John Logan of Water Energy Distributors for advice on installing a geothermal system. Dr. Logan connected George with New Energy Solutions of Standish who designed and installed a geothermal system consisting of two heat pumps, one for 1st floor radiant heat, and another for cooling and 2nd floor heating.

“It was great when I got all these smart people in the room together to talk about the synergy between renewable energy systems,” George says, “Our predictions are that the solar will provide around 50% of the electricity used for geothermal heating during the heating months, and 100% of my household ‘plug’ loads the rest of the year.”

Designing a home that is mostly renewable-powered requires being very conscious about energy use, and Longstreth’s home takes this concept to heart. His home is heavily insulated, consisting of a double-framed 2×6 + 2×4 wall system filled with compacted cellulose insulation, for a R40 rating in the walls and R60 in the ceiling. His home takes advantage of its south-facing orientation to incorporate passive solar features, such as windows installed for optimum solar gain and a special 1 1/2″ slab to collect passive heat.

Investing in Solar

As his project nears completion, George looks forward to a life of minimal energy bills. “The new home uses no oil whatsoever, very little electricity and very little propane. We bucked the attitude of ‘fly now, pay later’ to ‘pay now, fly later.’ The tight-fisted Yankee in me can’t let this bountiful renewable energy go to waste while we purchase oil from our enemies overseas.”

George estimates that his mechanical systems made up about 25% of his overall project budget, and that with state and federal incentives, his renewable systems were cost-competitive with installing a traditional heating system. “It’s a no brainer, and we’re already seeing results. After our first month, our electric bill went from around $80 to -$10! We can’t wait to see how it performs long term.”

Solar Road Tour Episode 3 – Net Zero Apartment Building in Portland, Maine

Friday, September 2nd, 2011

Thought you couldn’t build an apartment building in Maine without depending on fossil fuels? Think again! Paul Ledman proves with his new 3-unit dwelling in Portland that exceptional insulation and smart mechanical systems can work to make a home that requires no source of energy other than the sun… even in Maine! Even with tenants!

We’re proud to have this exceptional building in our backyard and thank Paul for taking the time to talk to us about this exciting project.

Net Zero Apartment Building in Portland, Maine Net Zero Apartment Building in Portland, Maine