Unity Homes’ Air Source Heat Pumps: Pulling Energy Out of Thin Air

By Rheannon DeMond

Bensonwood/ Unity Homes Energy and Sustainability Specialist

ASHP DIAGRAMHeat pump technology has been around for over a century, and even though the technology has advanced, the principles are still the same. There are some who are still critical about Air Source Heat Pump (ASHP) technology, but we at Bensonwood and Unity Homes prefer to use them whenever possible as they’re especially well suited for highly- insulated, airtight homes with very low heating and cooling loads. In fact, our building envelopes are so energy efficient that our smaller, open floor plan homes can often be comfortably heated and cooled with one central unit. Regardless of home size, however, Air Source Heat Pumps are an extraordinarily efficient and feasible option for our homes, and this article will cover why we think this technology is the best all-around choice.

Technology

Unlike combustion-based systems that produce heat at around 80-95% efficiency, ASHPs move heat from one location to another using the energy drive from the refrigeration cycle. This process is very similar to how a household refrigerator works.  The increased energy drive allows a heat pump to produce 100 kWh of heating and cooling energy using only 20-40 kWh of electricity, resulting in efficiencies of 200-350%.

ASHP IMAGEHow much electricity is consumed is dependent on the temperature differential between the outdoor and indoor air. In fact, a common reason people have shied away from using ASHPs in the past is because the efficiencies drop in cold temperatures, making these units not as ideal for cooler climates. However, recent advances in the inverter technology of these systems now allow ASHPs to operate down to -17°F, and produce heat at 100% of its capacity and efficiency down to 0°F.

Energy Usage

ASHP technology is efficient and here is a real life example to put it a little more in perspective:

For a 1,780 SF northern Vermont home that requires around 57.1 million Btus per year to heat:

Heating with #2 fuel oil would cost around $1,600 a year at current rates.

  • Heating with a propane-fired system would cost around $2,000 a year.
  • Heating with wood would be the least expensive option at around $850 per year (but the effectiveness is highly dependent on the user, stove design and kind of wood being burned.)

It should be noted that all of the aforementioned options use combustion, which we know is bad for the environment.

  • Electric resistance heat would cost around $2,500 per year and the impact that would have on the environment would be dependent on the source of electricity.
  • Air Source Heat Pumps can generate the same amount of heat for only $1,090 per year, and they can provide efficient cooling in the summer!

Environmental Impact

If the electricity used to operate an Air Source Heat Pump is generated by a renewable energy source, then the system has little to no impact on the environment. Oil, gas and wood-fired systems create heat using combustion. Combustion creates carbon dioxide, which is harmful to the environment and is a leading cause of unsafe emissions released into the atmosphere every day.

Using the same northern Vermont home as an example, the difference in electrical usage between electric resistance heat and the heat produced from an ASHP is around 9,500 kWh per year. A great way to look at those savings is how it will reduce the impact on the environment, as well as your wallet.

This EPA website allows one to input estimated energy offsets and see how those savings will reduce the impact on the environment. A savings of 9,500 kWhrs is the equivalent to eliminating the CO2 Emissions from 737 gallons of consumed gasoline, or 7,037 pounds of coal burned or 15.5 barrels of oil consumed. And that is just one year. Imagine what the environmental savings would be over 30 years.

Feasibility

Air Source Heat Pumps can be ducted, centrally located or zoned with multiple head units.  The system uses small copper refrigeration lines for connections, which minimizes required mechanical space and makes zoning much simpler. They offer a variety of head units that fit easily in both new and existing construction projects, and with their low operating loads these systems can be easily powered by a small renewable energy source.

Installation Costs and Return on Investment

We’ve already discussed how Air Source Heat Pump systems can save money on annual utility bills, but for something so efficient one would think it has to cost more money than conventional systems, right?  Wrong. These systems are very cost competitive with most other systems, and remember, they provide whole house cooling and heating, so they may even end up being less expensive.

So what is the return on investment on a system that will not cost the consumer any additional money? It is immediate, but on average this system will pay for itself in energy savings in less than six years!

 Cold Climate Operation

The one downfall to these systems is that at around -17°F there is a chance these systems will shut down and stop producing heat, which is what scares some people away. What these people do not understand though is how infrequently the temperature drops below minus 17°F in most of the United States. Even in the coldest climates this is not a common occurrence, so not using a system that is as efficient as this one because of that one fact is not the right approach.

A simple back up source of heat can be installed for use in these rare occurrences. In our homes we use electric resistance for back up heat, because it is inexpensive and can also serve as zone heating. There are also systems available with electric resistance back up heaters that will continue to operate into these low temperatures.

Other Types of Heat Pumps

After heating and cooling, domestic hot water consumes the most household energy, but luckily they also make a heat pump for that. Heat pump water heaters operate at high efficiencies, and have settings to ensure a steady rate of hot water.  When compared to electric resistance, oil and propane powered systems, these units will see a return on investment in less than three years. The only catch is that how efficiently they operate is dependent on the ambient air around the system, so installing a unit in a cold basement would not be ideal, but if you have a continuous source of heat to pull from, these units are a great and affordable solution.

Geothermal or Ground and Water Source Heat Pumps (GSHPs) operate using the same heat pump technology as air source, except they move heat using the consistently warmer temperatures of the earth and ground water.  Because of this they can operate at efficiencies of 300-600%. These systems are very popular in European countries with very strict guidelines for energy usage.

GSHPs are growing more popular in the cold climates of the United States, but they have high upfront installation costs and a small pool of qualified installers. Like most emerging and efficient technologies, it may take some time before these systems are offered at prices that offer an attractive return on investment.

Conclusion

Buildings are responsible for around 40% of the carbon emissions released into the atmosphere every day, and with the fluctuating cost and availability of fossil fuels, and threat of irreversible climate change, another solution is very necessary. With the advancements in heat pump technology and decreasing costs of renewable solar energy, achieving net zero energy consumption is not just feasible, but a great investment as well.

Aquatic Dreamhouse Required Fluid Construction Strategies

Pool-Centric Vision Posed Technical Challenges

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Faced with a significant technical challenge, Alfandre Architecture, PC and its construction company, EcoBuilders Inc., teamed up with Bensonwood to fabricate and install the large-span glulam timbers and insulated shell of this spectacular 6,000 SF timbered dream house — all built around a large 2,000 SF indoor pool — for their client, a retired couple in Putnam County, NY.

pool house living areaThe challenges included engineering the long timber spans of the pool room, humidity control and the sensitivity of the rocky build site, to name a few. Here, Bensonwood’s expertise in timber engineering, off-site fabrication of panelized assemblies and rapid on-site installation was instrumental in realizing the ambitious project with minimal disruption to the ecology of the home site.

The house, recessed into the bedrock of its 15-acre site, was designed by architect Rick Alfandre to complement its natural setting, with the pool room both anchoring the design and providing the homeowners with the physical, social and emotional benefits of their daily one-hour swim. To add to the ambiance, the light-drenched, four-bedroom, five-bath home has over 70 triple-glazed windows to draw the surrounding landscape into its interior.

pool in upstate ny dream houseGC and local construction company, EcoBuilders Inc. (owned and operated by Rick Alfandre) completed the foundation and walkout walls, first floor system, infill, window installation, mechanical systems, and finishes.

From this project, Bensonwood went on to contribute the timberframe and roof panels for Alfandre Architecture’s offices across the Hudson River in New Paltz, NY, for which Alfandre is seeking LEED Gold certification.

For more photos, visit our Houzz Page.

On the Boards: Cape Cod Pool House

cape cod pool house

In keeping with this month’s “Everyone into the Pool” theme, here is a charming little pool house we are helping fabricate on Cape Cod.

Designed by Rebecca Elsy Ribeiro of D. Michael Collins, Architects, the energy-efficient building features classic colonial carriage house styling with cupola and a sheltered overhang.

Bensonwood is crafting the timberframe, insulated wall and roof panels, and installing the Marvin Ultimate windows and a Marvin outswing bifold door. The timberframe consists of Douglas fir glulam timbers for the main structure and for the exterior timbers​.

Kenneth Vona Construction, a company that very much shares Bensonwood’s values, will be the builder. KVC is not only one of New England’s oldest and most respected custom builders, it is also one of the greenest.

pool house elevationsTheir ideal six-sided building envelope is one that breathes, insulates against losses, sheds water away for sustainability and remains energy efficient and reusable. Like Bensonwood, KVC believes a commitment to environmental responsibility results in immediate payback and comfort.

timber frame design for cape cod pool houseD. Michael Collins, Architects is a small, but high-quality design firm established in Natick, Massachusetts, in 1987. They specialize in new custom homes, additions and renovations, small scale commercial, institutional and historic restoration projects.

Most of the firm’s projects are located in Massachusetts, but they also have projects in Maine, New Hampshire, Vermont, New York, Colorado, Florida and the Caribbean.

We’ll profile more design-build collaborations with D. Michael Collins, Architects and Kenneth Vona Construction in the months ahead.

Our Building Systems Flawless in 3rd Party Inspection

2014.01.16_Panel shop (25) - Copy Four times a year, TR Arnold, a respected third-party “in-plant inspection agency,” or IPIA, is authorized by us to conduct unannounced inspections at our Blackjack Crossing production facilities. In voluntarily submitting to TR Arnold’s findings, our intention is to ensure that construction standards (state & local code, as well as our own stringent standards) are consistently adhered to.TR Arnold

Essentially, TRA inspectors go through each of our work stations inspecting up to 120 certification elements. As part of this quality control process, TRA inspectors are authorized to, “…reject non-compliant units, to withhold labels and to inspect all finished units produced and labeled prior to a unit found deficient and subsequent to the last unit inspected at the station where the deficiency occurred.”

One such audit has just concluded, and we’re pleased to report that of the many assemblies inspected, no non-conformance issues were discovered and we were found to be in complete compliance.

According to Building Systems specialist, Scott Bosworth, “This is really a big deal because of our building techniques compared to other, very different kinds of prefab home builders. For example, with “Double-Wide” manufactured homes that travel down the highway in halves, there are only two certificates required: one for the left side of the house, and one for the right side. With our many panelized assemblies (that are later raised at the build site), there are 120 or more certification elements that can be inspected prior their leaving our production facilities.”2014.02.07_Panel shop (8)

As Scott elaborates, “And because of the kind of closed-panel, or closed-cavity assemblies we fabricate offsite, building inspectors at the home site appreciate seeing certifications created by independent, in-plant inspectors who have seen the panels come together at the point of manufacture. Therefore, getting a full compliance report from a third-party administrator is huge,” adding, “A perfect score from a company like TR Arnold not only helps affirm our own quality control efforts, but in some cases, having the certificate can also help reassure a local on-site building inspector regarding enclosed areas he or she cannot readily see into.”
2014.02.07_Panel shop (2) - Copy
According to Bensonwood/Unity Homes production head, Kevin Bittenbender, who is in charge of compliance control and was instrumental in setting up independent plant oversight, “We’ve been building to the highest quality standards for years. It’s just what we do. It wasn’t much of a change in our process, or product, to meet TR Arnold’s standards. We simply had to clearly explain and document our product, and how we work. Our standards are higher than what is needed for code, and receiving positive results from their inspections is a nice confirmation that we are successfully building to the highest standards in the industry.”

Texas Prefab Lake House

austin texas lake house 1 An admitted This Old House fanatic, Matt Risinger had grown up watching the PBS television series when, in 1989, a program aired that would change his life. The Wickwire Barn Series—the second time Bensonwood had appeared on the long running home improvement program— featured Tedd Benson and an old barn being converted to a new house: a project Matt had dreamed of building for himself someday. It became the seminal moment in his decision to become the best builder he could be.

Mette Aamodt AIA and Andrew Plumb AIA

Mette Aamodt, AIA & Andrew Plumb, AIA

Fast forward nearly two-and-a-half decades, and architect Andrew Plumb of award-winning Aamodt / Plumb Architects in Cambridge, Massachusetts, is looking for a builder to help assemble and finish out a highly custom modern timberframe ranch home he designed for a special client he has known for years. The lakeside projectTEXAS PREFAB, expected to approach near Passive House standards, would have an aggressive build schedule of one year, and it needed to come in at a fixed budget—so Andrew knew it had to be done right. His first thought was to call Bensonwood for its expertise in the sustainable fabrication of high performance homes, and his second thought was to call green builder, Matt Risinger, now of Risinger Homes, to say Tedd Benson’s company would be fabricating and installing the home’s shell. With the name “Benson” still fresh in his mind after a quarter century, Matt jumped at the opportunity. The home plan, viewable on the Aamodt / Plumb website, is a interpretation of the Texas Ranch vernacular, with two gabled buildings joined by a light-filled entry hall. Designed for a young family, this prefab home strives to create a relaxed, contemporary feel through the use of natural and reclaimed materials, ample daylighting and a thoughtful relationship to the site.

MATT RISINGER

Austin, Texas green builder Matt Risinger

“We sought to create a warm modern atmosphere through the interplay of simple forms, materials and natural light,” says Plumb. The play of the modern and rustic is achieved through material choices and elemental forms. Japanese (Shou Sugi Ban style) charred wood siding, mesquite and ash flooring, and an oversized FireRock masonry chimney and fireplace add a dramatic touch both inside and out. texas green prefab architects renderingThe light-filled open interior, with its elegant but simple timberframe, richly-finished flooring and high-end fixtures, perfectly complements the striking exterior while framing the surrounding views. Matt Risinger asserts that, “The most sustainable house is a pretty one. Architect-designed houses will be loved and cared for because they are beautiful. Ugly houses will fall into disrepair and be torn down eventually.” fireplaceBeyond the aesthetics, this house was designed to coast through the hot parts of the day with little need for air conditioning. This is achieved through rigorous attention to air sealing and our panelization process using super-insulated walls. All the exterior claddings are installed over a rain-screen air gap. The roof, wood siding and even stucco have an air gap behind them so that the potential for water intrusion over the life of the building is minimized. Risinger installed super-efficient mechanical equipment to make the best possible use of the resources consumed. 95%+ efficiency gas equipment, super high-efficiency AC, Ultra-Aire Split Dehumidifier prevents mold and allows the owners to keep thermostat settings high when the building is unoccupied.YOUTUBE TIMELAPSE IMAGE You can watch Matt Risinger’s YouTube video of the home being assembled here. Once the project is completed and finish photos become available, we will revisit this home to detail its space plan. Stay tuned.

Sunday River Ski Retreat: The Best of All Worlds

Tedford ElevationSome ski homes high on the mountain have beautiful views down the valley. Others near the base lodge typically have great views up the slopes. This timberframe home at The Glades at Ridge Run, a new slopeside residential neighborhood at Sunday River Resort in Newry, Maine, captures both.

Situated in the western mountains of Maine just three hours from Boston, Sunday River Resort has long been one of New England’s most popular four-season playgrounds, but what is so special about the property that owners Meredith and Jamie found here is that it sits uniquely midway up the mountain with expansive views above and below.

Though Meredith and Jamie had just completed an extensive renovation on another home and weren’t anxious to begin a new construction, this was the first time a ski-on, ski-off home opportunity was available at Sunday River, so the couple knew they had to jump on it. They were also motivated to replace an old beloved, but small, ski lodge they had outgrown. Sensitive to the feeling of transplanting their relatives away from a getaway that had been in the family for years, they wanted an open concept floor plan with the feel of a true home. They also wanted to maximize family interaction, and minimize the size of the house to facilitate that function—as well as for aesthetic and environmental impact motives.

sunday river family ski lodge renderingPast renovations had taught Meredith and Jamie to be flexible but decisive, which helped in this first new house project. They also knew from experience that “design by committee” was something to be avoided, rather it was better to create a team dynamic between client and architect that respected roles and responsibilities, but also valued input from all parties. The mutual trust that developed allowed changes to be made fluidly and without conflict.

The Bensonwood design team of Randall Walter, Curtis Fanti and Dave Levasseur, all avid skiers in their own right, were excited to create this special place from a perspective of years spent skiing and snowboarding. Their personal insights proved invaluable in informing practical aspects of the design.

The architectural review process at the resort and the corresponding design standards requires development that complements the surrounding natural setting; minimizing the impact on the landscape while allowing for individual freedom of design to suit the needs of each homeowner. A common theme, described as a Northeast Cottage with Adirondack and Shingle Style influences, dictates the use of building materials, colors, landscaping and building style at the resort. The style is best illustrated in Summer Cottages in the White Mountains by Bryant F. Tolles, Jr. (2000), in which the use of native materials blended with natural colors provides an effective link to both the local environment and the great cottage architecture of the early 20th century.

Sunday river ski lodgeWorking closely with the clients, the resort, the civil engineering firm Main-Land Development Consultants, Inc., and the town zoning board, Randall was able to design the energy-efficient home into a challenging site with steep terrain and protected wetlands. He was able to navigate the regulations and arrive at the design—a traditional Adirondack timber lodge style with a modern twist on the gables to accommodate the views—in a way that pleased all the parties involved. In the end, the review board process was easy and the owners got a home that fit their needs and respectfully fit the mountain landscape.

Another welcome test for Bensonwood is the truncated construction timeline. With designs finalized this past spring, the owners wanted to ski from the home this coming winter. Anxious to prove that even a custom 3,900 SF mountain home on an undeveloped site could go up in record time with our Open-Built® systems and offsite fabrication, the Bensonwood team embraced the challenge. Rapid onsite assembly will also help cut build times in half over conventional construction, effectively giving the homeowners an entire extra season to enjoy the resort.

ski deckLike many of Bensonwood’s mountain and shore homes, the house features gable roof lines, with one important distinction: these gables, dormers and bump outs will have asymmetric rooflines that permit both mountain and valley vistas as well as views of arriving and departing skiers. These roof angles, along with the heavy, rough sawn, red cedar clapboards, work to give the exterior its distinctive look: at the same time both traditional and contemporary, while the property’s southern exposure allows for plenty of natural daylighting and passive solar gain.

On the inside every detail of the sanctuary, which will accommodate three generations of family, has been strategically planned. The owners wanted to maximize the use of space, and that included the kids’ space on the ground level, with the fun feel of a ski resort locker area. The ground floor has a rustic lumberjack-inspired kids zone, with a mud room off the garage, an open play area, a game room, a guest bedroom, a bunkroom with three beds, and facing his and hers bathrooms.

The first floor has a large open space plan with cathedral ceiling and a gathering area across from the kitchen/pantry and adjacent to the dining area. The dining room will have a long, farmhouse-style table with benches accommodating 10 or more. The second floor plan has three bedroom suites, each with their own bath, and a balcony open to the gathering area below.

sunday river ski lodge renderingPerhaps the most unique feature of the project, however, is a very innovative ski-on, ski-off deck. The custom deck required Randall to create a multi-functional outdoor living space with views up and down the mountain in a style that also satisfied design review board restrictions. His solution was adjust the roof pitch and angles so skiers on the deck will still be able to enjoy the views, as he had done on the main house.

Mindful of the homeowners’ sensitivities to limiting the home’s size, he placed the deck atop the garage so skiers will have easy to the home’s bathrooms and kitchen on the main floor when they ski home at lunchtime. Unique features include a hot tub—not tucked away in a secluded spot as is often seen—but in the open air on the sheltered ski deck so all guests have ready access. There are also ski and snowboard racks, overhead heating elements, a fireplace and a hot tub on the deck.

FLOORPLANOne of the most creative elements of the home is one the clients devised. Rather than the traditional guest book for visitors to sign, the couple will immortalize them with a round timber into which they can carve their names and the dates they stay, creating a family legacy crafted in wood that will last for generations—just like the home.

Architect Randall Walter predicts that, like many vacation homes Bensonwood has crafted over the past 40 years, this house will be used much more than originally intended, because families often discover they enjoy spending time in them so much more than in their primary residence.

 

 

 

Bensonwood Designer Tim Olson Wins AIA-VT Emerging Professionals Award

Tim Olson Common Core Library

Bensonwood Design team member Tim Olson took Third Place in the AIA Vermont 2014 Emerging Professionals Network Design Competition: “Engaging the Public Library.”

The Emerging Professionals Network of Vermont is a component of AIA Vermont, and serves local emerging professionals by representation on the AIAVT Board of Directors, while in turn educating members about important developments within the design and construction industry. The EPN also serves a larger purpose by organizing events and projects that bring together students, young designers and experienced architects, in order to promote architecture and good design in the community.

Contrary to popular belief, public libraries are not a declining institution. Over the past 12 years (a period experiencing a dramatic expansion of the internet as well as a shrinking of public funding) yearly visits, program attendance and total income for Vermont public libraries have increased by more than 50%. Therefore, the issue is not making libraries relevant again, but strengthening the relevance of libraries for the future.

The competition asked emerging architectural professionals from around New England to design an architectural intervention that reinforces and expands the relevance of the public library.

Competitors specifically addressed:

–          How can architectural interventions catalyze the exchange of ideas in a library and its community?

–          What programs and amenities can attract new user groups while maintaining existing patrons?

–          How is a public library a distinct form of access for information, knowledge and discussion?

–          What is the contemporary function, role and identity of the New England public library?

Tim Olson AIA Vermont Board

Entries came in from emerging professionals in Vermont, Massachusetts, New Hampshire, Connecticut and Rhode Island, with designs in the form of additions, renovations, and satellite structures under 2,000 square feet. Winners were selected by a jury of architects, librarians and community members who considered graphic clarity, originality and cohesiveness of concept.

Tim’s entry, The Common Core, proposed that libraries provide an essential and rare type of civic space where populations can collect and engage in the social construction of community through the cohabitation of a shared resource.

Olson imagined a Public Library with a central space at its core that could be accessed and utilized by a larger cross section of the population. This space could be activated both during normal library hours for children’s programs, reading rooms and study space. In the after hours, or for special events the space could transform into a lounge, community living room, or an ad-hoc movie theater—a space designed to host book openings, film screenings, public lectures and art events. The Common Core offers the insertion of a “stage” and adjoining “fly loft” to make this diversity of programs possible.

The exhibit will be displayed at the Pierson Library in Shelburne, Vermont, and then travel around the state with the AIAVT Design Awards.

The Common Core offers the insertion of a “stage” and adjoining “fly loft” to make this diversity of programs possible. By radically compacting furnishings into a vertical space, an expansion in the programmatic potentials can be accomplished while maintaining the urban location, historic facade and footprint of the New England Public Library.

The exhibit will be displayed at the Pierson Library in Shelburne, Vermont and then travel around the state with the AIAVT Design Awards.