In a recent blog, we detailed two high performance Ridgeline models from our Renew Collection.  But for those customers who love the awesome views, delightful uniqueness and high customization of our signature round homes, our 360° Collection has always been a highly sustainable option.  Read below for two examples of recently finished 360° Collection projects with interesting technical features.

Up on the Mountain

Tyler and Chelsea moved to Western North Carolina from California. Building on a secluded piece of land atop a mountain, where sounds of the idyllic valley below can be heard wafting up the ridge each morning, sustainability was hugely important to their goals. They wanted a home and office with a low embodied carbon, and low enough energy consumption to be able to go totally off-grid. Our track record of building high performance homes, and our values as a B Corp, drew them to Deltec. The power of our 360° Collection to capture a view like no other put them in a round home.

Their design used a 2-story 1200 square foot round model on a slab foundation, plus a 2-story wing for stairs, and a single-story wing for an attached garage. As part of a strategy for superior insulation levels in our mixed-humid climate, they chose our “Deltec Energy Wall,” an upgraded perimeter wall option. This open-stud wall system, assembled in our factory, uses 2×6 stud framing (compared to the industry standard in North Carolina, which is still just 2×4) for greater strength and thicker cavity insulation values. It adds to that an exterior layer of continuous foam insulation, a useful strategy for wrapping the entire house in an extra blanket of insulation and reducing what energy nerds call “thermal bridging”: that is, the tendency for heat to escape more quickly through areas of lower insulation value (such as the wood studs). The structural headers of the Deltec Energy Wall are insulated in our factory with recycled scrap foam material, and our craftsmen apply a gasket at the perimeter of the plywood sheathing to seal it to the wall, increasing the home’s total air-tightness. The home captures views using windows from Marvin Essential collection, also installed in our factory.

Energy systems were a critical aspect of their design process, since running power to this remote site proved to be a challenge. Rather than be daunted, this challenge spurred Tyler to accelerate his eventual plan for the site, which was to install a solar electric array, battery energy storage, and a backup wood stove and propane generator, all to allow him to take his home off-grid if he wanted. Yet he also wanted to limit propane use and take advantage of the variety of very high efficiency all-electric appliances that are common in this region for high performance heating and cooling, such as two ducted mini split heat pumps, a heat pump water heater, and an induction range. He also needed to provide power for his Tesla electric vehicle charger.

People often associated “mini splits” with the iconic, ductless “white box on the wall” that blows heated or cooled air directly into the room, eliminating air ductwork. And indeed, removing or reducing the amount of ductwork in a home can make a difference for heating and cooling energy costs, as ducts tend to leak some amount of air away, and constrictions in the duct runs can force the need for larger blower fans and greater capacity equipment than what might otherwise be needed. But mini splits have a couple of other distinct technological advantages over the “conventional” ducted heat pumps that commonly provide heating and cooling to homes in the southeastern US, advantages that make them highly relevant to low energy homes.

One such advantage is an improved refrigerant technology that allows some models to deliver warm air even when outside temperatures are very cold without relying on a backup source of heat, a critical function in this mountainous climate zone that does still see cold weather extremes. The other advantage is an ability to vary the heating or cooling output based on conditions. This is rather like the advantage a car with a CVT transmission might have over a (hypothetical) single speed car: the system has nearly infinite”gears” available to it and can constantly choose the correct “gear” to run in to deliver the most comfort at the lowest energy use. This is an important feature of an electric heating system in a home with an off-grid solar array, as historically, even highly efficient electric heat from heat pumps still draw a lot of electricity at once, and can drain solar batteries very quickly. By contrast, the use of multi-stage or infinite stage heating systems like mini splits can allow the lowest possible electrical draw for the given weather conditions. While a sizeable battery bank is still required, it becomes more feasible to provide some heating energy from these highly efficient electric heat pumps, with a wood stove as an ultimate backup.

Meanwhile, the indoor components of mini splits actually come in a variety of “flavors,” from the iconic wall mounted unit, to floor mounted units, to ceiling cassettes, and…yes, even ducted air handlers. The latter offers the ability to serve multiple smaller rooms with one air (still small) handler, reducing system costs (vs putting one white box on the wall in every single room), while still delivering the low temperature and variable speed advantages that mini splits offer. Based on the size and lay out of the rooms in Tyler and Chelsea’s plan, one ducted mini split per level made the most sense.

I mentioned in my previous blog about the benefits of heat pump water heaters for all-electric homes, but they can be challenging to locate in some floorplans in a place where they get enough airflow to operate, and where their noise and cold air doesn’t bother the homeowner. In Tyler and Chelsea’s case, the mechanical room, while tucked under the stairs, was still a bit smaller than recommended for a heat pump water heater, so we attached air ducts for it to pull in it’s warm air and dump it’s cold air to outside. Although this reduces the efficiency somewhat, it’s still much better than a standard electric resistance water heater, so it was a worthwhile tradeoff to stay all-electric.

Since they were building here in our home region, they used our in-house builder, Deltec Building Company, to act as general contractor for the project. The home is Energy Star Certified, receiving a final HERS score of -17. It uses a 10KW solar array with 5 KiloValt HAB Batteries and a 13KW Generac backup generator. The off grid solar array and equipment was designed and installed by local solar contractor, SolFarm.

Deep in the Snow

Shan was an acoustical engineer with a background as a hobby conservationist. He and his wife Linda were also looking for an energy efficient home that could capture some unique views on their property in southern Alaska.

Alaska can be a very challenging place to build. Building materials can be expensive and time consuming to get to the jobsite, as they often have to be shipped in by boat. The buildable time frame is short. The amount of available sunny hours to feed a solar electric system, if that happens to be your goal (as it was for these clients) are not generous, and the temperature extremes are harsh. Energy rates are also nearly double what they are in much of the continental US, so every measure to build a more efficient home is even more valuable.

To meet the design challenges of the harsh local climate, Shan and Linda chose our upgraded “Double Stud Wall” option with their floor plan, which used a 900 square foot base round model with two wings. Our Double Stud Wall option uses two layers of 2×4 studs, in order to create a nearly 10″ thick wall to pack full of insulation. To take full advantage of this highly insulative wall, highly insulative windows should be used as well, which meant upgrading from the more common double-pane windows to higher performing triple-pane windows on the north, east, and west sides of this home. Thick insulation values in the roof, and a conditioned crawlspace built with insulated concrete forms, cap off the super insulation strategy for this cold climate.

Like Tyler and Chelsea, Shan and Linda were interested in having an on-site solar array with battery storage, in their case to provide backup power in situations where winter storms cut off the grid. And they also wanted to limit their system’s reliance on propane or other fossil fuels when doing so. Due to the cold climate and limited sun, the energy-using systems in the home had to be chosen very carefully indeed.

First, the heating demand needed to be reduced as much as possible. In addition to the super insulation strategy described above, air-tight construction was extremely important. In addition, the lay out of the home used passive solar design strategies to harvest and hold on to the sun’s heat, by minimizing window glass areas on the north, west, and east, but increasing it on the south, where the sun (when available) would shine in throughout the day. A special low-e coating on these south facing windows designed to let in as much of this heat as possible, combined with a dark, dense tile floor in the sun space to absorb the heat, makes the most of this available warmth, storing it in the building materials, making the interior temperatures more stable. Of course, a mechanical heating system is still needed, and surprisingly, an electric mini split heat pump still made sense, even in this cold climate, paired with a backup wood stove, and backup electric baseboard heat. Their heating system design used a combination of a ducted mini split for the back half of the plan, a ductless mini split for the living area, and a ductless for the main bedroom suite. And since water heating is the next biggest energy expenditure in a home after heating, the nearly unsurpassed efficiency of a heat pump water heater was still the winner, this time located inside their conditioned crawlspace.

The home was tested for compliance with Alaska’s Building Energy Efficiency Standard (BEES) system, received 6 stars, and a final blower door test of 1.19ACH50. After a winter of living in the home, the homeowner estimates that they consume around 4000 kilowatt hours a year, and generate around 7000 with their 7.6KW solar array (the difference is stored in the backup batteries).

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A custom 1500 square foot round home in Mars Hill, NC. Open to the public to allow our costumers to come and see what net-zero living feels like in the round!

• HERS Score: 7
• Certifications: Energy Star for Homes, NC, GreenBuilt Platinum and Net-Zero Certified
• Projected Yearly Energy Savings: $1061 (compared to typical new construction)

The Story

With a design driven by passive solar principles and the with uniquely air-tight and super-insulated building envelope made possible by Deltec’s panelized building shell, this model allows all to see and feel the way we recommend that all of our customers build their homes. Mechanical systems were selected to offer highly efficient comfort in a climate that samples the extremes seen across the country: cold winters, hot summers, and considerable year-round humidity. The finishes were selected with sustainability and affordability in mind: FSC certified wood flooring, LED lighting, zero-VOC paints, metal shingle roofing with 90% recycled content and a lifetime warranty, are just some examples of the products on display. The innovation center is also a place of learning for us. We’re using it as a laboratory, to further building science by testing for wall moisture content, and to learn more about energy use in homes.

Technical Features

• Deltec Energy Wall (R24)
• Raised heel truss with spray foam, insulation (R30)
• Insulation under entire slab (R10)
• Extreme air-tightness (1.7ACH50)
• Passive solar design with thermal mass floor and windows Low-E tuned for solar heat gain
• Mini-split heat pump with one ductless and one ducted head
• Heat pump water heater
• ERV fresh air ventilation system
• 5.12 KW solar array

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A custom Ridgeline model from our Renew Collection in Asheville, NC

• HERS Score: 6
• Certifications: Energy Star for Homes, NC GreenBuilt Platinum and Net-Zero Certified, winner of Asheville Parade Of Homes Greenest Home Award
• Projected Yearly Energy Savings: $1450 (compared to typical new construction)

The Story

Amy and Jennifer turned to Deltec for the green home of their dreams. As avid gardeners, birders, and naturalists, creating a home that was a habitat for themselves, and for the wildlife on the site, was an important goal. The use of third party certification through NC Green Built and Energy Star for Homes helped our building company focus on land preservation, water conservation, and energy-efficiency details throughout construction.

The Technical Features

• Deltec Energy Wall with custom window package featuring high heat gain windows on the south and stained concrete floors as part of a passive solar design strategy
• Combination ducted and ductless mini-split heat pump system
• R30 spray foam in the roof
• R19 fiberglass batts and exterior continuous insulation for R24 total in the walls
• Super insulated slab foundation
• Heat pump water heater
• 5.24 kilowatt grid-tied solar array
• Zero-VOC paints
• Rainwater collection
• Handicap accessible design
• Recycled content fiberglass insulation

The post An Award-Winning Ridgeline appeared first on Deltec Homes.

Jim and Gail of Abingdon, VA grew up as environmentalists and readers of Mother Earth News—which is where they found Deltec Homes. They wanted to build a home that incorporated the oldest, yet most effective green technologies: passive solar design. They used the Deltec Homes’ Crescent Chalet Sweep design to get maximum window surface area on the south side of the house, while also allowing an incredibly open floorplan.

Deltec’s Green Building and Sustainability Manger worked with them extensively on the passive solar aspects of the design: adjusting window glass, overhang lengths and thermal storage potential of their concrete slab to perfection. Now the home, currently under construction, is designed to hardly even need a heating system in the winter at all.

The Green Technicalities

Deltec Energy Wall with spray foam insulation (R30); sealed, conditioned attic with spray foam insulation (R42); Superior Wall basement, (R24); R10 underslab insulation. Exposed, stained concrete floors on both levels for thermal mass. High efficiency, multi-stage heat pump and AC system with mechanical fresh air ventilation, topped off with a 7 kilowatt solar electric array.

The Design

A Crescent Chalet is a Deltec round home, stretched into an oval. A Crescent Chalet Sweep is a Crescent Chalet with swept ends, creating a long south-facing side that is perfect for a highly passive solar design. This home is a great testament to the flexibility of a Deltec home.

1st Level

2nd Level

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