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The natural ventilation strategy incorporates the windows from lower and upper levels.

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The multiple bedroom windows increase cross-ventilation.

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"The building-s three tall spaces (the flat roof section over the stair, the tall spaces on the south side, and the space over the garage) all use convective stack-effect to ventilate and cool the house in the warmer summer months. Stack-effect works according to the pressure differences of warm and cool air. In the summer, cool air is drawn in via windows and doors at the lower level while warmer air floats up — due to the natural flow of lighter warmer air — and is flushed out at windows high in the house. The upper windows and open ceilings work best when they are as high as possible. Wind velocity increases with height, the higher the windows are, the more stack-effect is generated."

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Wall thickness: 10" average (range from 5"-14")

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Roof: Energy Star (light cool color to reflect solar energy, approximately 85% of total roof area) painted steel standing-seam roof. This roofing material is fully recyclable, very durable, and should have an installed life of at least 40 years.

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Insulation R-values:

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Building tightness: Specific attention was given to detailing the seams and prevention of thermal bridging and energy loss through a tight building.

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Windows:

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Primarily natural ventilation for the summer. The office/bedroom has dedicated cooling and air filtration, however, air conditioning is possible for the whole house.

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"The home is heated by a high efficiency boiler using a combination of solar energy and natural gas. All the heating will be delivered via radiant heat, with no forced air. Radiant heating delivers more comfortable heat per BTU than comparable forced air systems, and typically uses less fuel."

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The radiant floor delivery system is called Warmboard for wood floors.

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Backup heating with a high-efficiency gas

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Electric backup for domestic hot water

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Garage heated by a gas-fired blower

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Solar thermal drain-back system for space heating and domestic hot water

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Three 120-gallon Rheem storage tanks

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Eight 4'x8' (256 sq. ft.) AET flat plate collectors installed at 60-degree angle

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Grundfos pump 2699

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15-gallon Eagle Solar drain back tank (see diagrams)

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Storage tanks and the lines to the heating system are separate for the domestic hot water and space heating for code reasons.

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Daylighting: Locus

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Energy Performance: Gausman & Moore

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Renewable Energy: Fchart and Visio drawings by Innovative Power Systems (IPS)

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"One of the options initially considered was tearing down the house and building new. Upon review, the owners declined to pursue this path for a number of reasons. First, they felt a significant demolition would be drastic — both to them and their friends and neighbors. Second, they felt it wasteful to demolish a house with 'good bones', one built on a solid foundation with quality framing materials. Third, they wanted to save as many of the site's valuable trees as possible — an impossible task if removing the existing house entirely."

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"When initially working with Locus, the owners encouraged them to design a house that fit conceptually with other buildings on the block. They asked for a house built to last — physically and aesthetically — for decades, even centuries. In addition, they asked Locus to employ design strategies to harness the technologies and materials available in the 21st Century."

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"The owners' interest for the view, then allowed Locus to provide ample glazing for opening up the view, which in turn increased the daylighting opportunities."

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"In the end, the owners requested that the design address energy efficiency strategies and to be resource efficient."

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From the beginning it is important to incorporate the contractors into the process to get them onboard with what is going on. This means bringing in the general contractor as soon as possible, as well as the mechanical and structural contractors to work together with the renewable energy installers. It is really important to work with people who know what they are doing with renewable energy systems. This will help provide a positive experience with the process which is necessary to get the general contractor to continue to be involved in including renewable energy in projects and to encourage their influence in the market.

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While incorporating renewable technologies, it is also important to make sure all the easy things are addressed, such as better insulation, smaller footprint, and shaping the volume for passive heating and cooling reasons.

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Establish a relative budget to design, install, and select types of renewable technologies for practical purposes. This means being able to decide from the beginning about the option chosen and not continuing to add new options.

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Design keeps changing for the renewable energy system as other elements of the building change. Delivering the product becomes more challenging and requires more coordination if the design is not locked in earlier in the project. Again, this is why the renewable energy system needs to be part of the dialogue during the design phase.

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One design challenge was how to place carpeting over the solar thermal radiant in-floor heating. The solution was to use dense carpet underlayment that was more conductive than other products typically chosen in the areas that were carpeted. Also a dense wood species was combined with the radiant flooring in other areas. The radiant floor product called Warmboard was used under both carpet and hardwood floors, but the way they went over it differed in the two areas.

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In the construction phase when several contractors are involved, it is important that one party is in charge of the entire operation. This would make clear what everyone's role would be, based on the system designer's recommendations.

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The collector installation went very smoothly because the roof was designed specifically for the collectors chosen. The outcome of the installation is working well and performance is good.

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Once everything was installed it was essential for the heating system designer and the solar system designer to fine-tune system controls on site. This ensures that the solar system is the primary heat source and that the fossil fuel system acts as a backup.

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A successful approach was taken for engaging the neighbors to be exposed to the project and learn about the design choices that included renewable energy and high performance building:

"Because some of these materials and technologies do differ from the materials and technologies available to early twentieth century homes like others on the block, the owners invited the neighborhood to review the plans, elevations, and a building model of the proposal (with the flat-roofed stair tower design) in 2005. Many of their neighbors stopped in, and I spent several hours answering questions about the design, the mechanical systems, the roofs, as well as the shape of the exterior and how it was derived. To my knowledge, the neighbors have been supportive of the project. Anecdotally, from what the owners and I have heard, the neighbors view the project favorably — at least in part due to the environmental aspects of the design."

(Source: Locus Architecture Energy Efficiency Strategies, Wynne Yelland, Locus Architecture)

This lesson is essential in order for renewable technologies to gain more support in the industry and in residential communities. When introducing new ideas to a community, more support for the project can be gained by sharing with community members, by educating them about the rationale for the choices made, and answering their questions while addressing their concerns.

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Many of the choices made were to build a building that would last and be energy-efficient.

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14'x7' Green Roof @ 8–9% of the overall roof area