Retreat in North Atlantic Seeks Energy Independence

Second Peninsula (near Lunenburg), NS

Jan 8 2009 By Rob Wotzak | 1 comments

General Specs and Team

Location: Second Peninsula (near Lunenburg), NS
Bedrooms: 4
Bathrooms: 2.5
Living Space : 2780 sqf

Builder: Norman Whynot, Kinburn Properties
Architect/Designer: Solterre Design
Engineer: Weyerhauser (truss system), Nu Air Ventilation (enerboss and HRV(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. design)

Construction

Foundation: slab on grade over 2 in. XPSExtruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North America, XPS is made with ozone-depleting HCFC-142b. XPS has higher density and R-value and lower vapor permeability than EPS rigid insulation. insulation (R-10); hydronic in-floor heat, ceramic tile, and engineered hardwood flooring
Walls: 2x6; fiberglass insulation and 1-1/2-in. rigid XPS insulation sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. (R-26); 5/8-in. gypsum board for additional thermal massHeavy, high-heat-capacity material that can absorb and store a significant amount of heat; used in passive solar heating to keep the house warm at night.
Roof: vented, TJI rafters with fiberglass batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. and metal roofing (R-40, Trus Joist)
Windows: double-glazed, low-eLow-emissivity coating. Very thin metallic coating on glass or plastic window glazing that permits most of the sun’s short-wave (light) radiation to enter, while blocking up to 90% of the long-wave (heat) radiation. Low-e coatings boost a window’s R-value and reduce its U-factor., argonInert (chemically stable) gas, which, because of its low thermal conductivity, is often used as gas fill between the panes of energy-efficient windows. -filled; SHGCSolar heat gain coefficient. The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. = 0.41, U = 0.32, R-3.13 (Marvin)
Garage: detached

Energy

Heating/cooling: in-floor radiant heat in main floor slab-on-grade; hydronic radiators on the second floor; glycol-filled solar collectors with 100-gallon storage tank; gas-fired on-demand boiler (17,000-140,000 btuBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. , Takagi); passive cooling
Water heating: same as space heat
Annual energy use: 84 MMBtu

  • Passive solar heat
  • Slab providing thermal massHeavy, high-heat-capacity material that can absorb and store a significant amount of heat; used in passive solar heating to keep the house warm at night.
  • Solar domestic hot water and hydronic radiant heat
  • Window layout provides abundant daylightingUse of sunlight for daytime lighting needs. Daylighting strategies include solar orientation of windows as well as the use of skylights, clerestory windows, solar tubes, reflective surfaces, and interior glazing to allow light to move through a structure.

Water Efficiency

  • Rainwater collection from metal roof to 4,000-gal. cistern with backup dug well
  • Low-flow toilets
  • Low-flow faucets

Indoor Air Quality

  • Low-VOCVolatile organic compound. An organic compound that evaporates readily into the atmosphere; as defined by the U.S. Environmental Protection Agency, VOCs are organic compounds that volatize and then become involved in photochemical smog production. paints
  • Prefinished hardwood flooring
  • Whole-house ventilation with HRV(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air.
  • Detached garage
  • FormaldehydeChemical found in many building products; most binders used for manufactured wood products are formaldehyde compounds. Reclassified by the United Nations International Agency for Research on Cancer (IARC) in 2004 as a “known human carcinogen."-free composite wood products

Green Materials and Resource Efficiency

  • Renewable strawboard used as interior wall surface
  • Local hardwood flooring on upper level
  • Engineered wood for all spanning members
  • FSCNonprofit organization that promotes forestry practices that are sustainable from environmental and social standpoints; FSC certification on a wood product is an indicator that the wood came from a well-managed forest. solid birch treads on open stair system

A Study in the Efficient Use of Natural Resources

Perched on a coastal peninsula near Lunenburg, Nova Scotia, this contemporary home is used mostly as a summer residence, but with a design that includes active and passive solar heat, a high-thermal-mass radiant slab floor, and thorough air sealing and insulation, it's a nice place to be in any season.

Year-round comfort
Owners John and Rosemary wanted to create an environmentally responsible home that could some day run completely off the grid. The six solar hot-water collectors push the house toward energy independence, but the extreme North Atlantic conditions warranted adding a supplemental gas-fired boiler for winter heat. A heat-recovery ventilator(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. brings fresh air into this super-tight home without bringing in the cold.

Many of the energy-efficient design elements really shine in the warmer months, which is when the house gets the most use. An open floor plan with 19-foot ceilings and operable windows at different heights allow the cool ocean breeze and plenty of sunlight to pass through the house. Ceiling fans help the house stay cool when the winds are calmer.

Natural resources used wisely
The metal roofing does more than keep the weather out. It directs rain into a 4,000-gallon cistern, for both domestic water and irrigation. So far, the cistern has been the sole water provider, although the home does have a backup well. FSCNonprofit organization that promotes forestry practices that are sustainable from environmental and social standpoints; FSC certification on a wood product is an indicator that the wood came from a well-managed forest.-certified birch stairs, interior paneling of renewable strawboard, and the engineered lumberLumber made by gluing together veneers or strands of wood to create very strong framing members; stronger and less prone to warping than standard framing lumber and can be made from smaller-diameter trees, saving old-growth forests. used for all structural spans add up to a home that was frugal with resources from the start.

New inspires old
This was the first time John and Rosemary built a home, and it was also their first experience with sustainable design. It went so well that they recently incorporated similar principles into the renovation of their 1850s home in England.

Lessons Learned

In a perfect world we would use the best techniques and choose the best site and every building would perform to its optimal level. Unfortunately, needs, wants, and available resources don't usually make best-case scenarios practical. Magnificent ocean views mean an exposed site with no natural shelter from the North Atlantic winds.

Taking advantage of these views demanded plenty of windows on the north side, which further complicated the construction of a well-insulated home. Solterre Design applied its passion for and expertise in energy efficiency to a challenging situation and, to the delight of John and Rosemary, created a durable, comfortable, energy conserving home.


Rob Wotzak is assistant editor at GreenBuildingAdvisor.com

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Image Credits:

  1. Jennifer Corson

1.
Tue, 04/21/2009 - 16:30

NS Getaway...
by Richard Medlock

Another superb example of design, thought, engineering, construction, and, well, everything. Kudos to this project and all it's people too!


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