Connecticut's First LEED Gold Home

South Glastonbury, CT

Jan 13 2009 By Rob Wotzak | 6 comments

General Specs and Team

Location: South Glastonbury, CT
Bedrooms: 5
Bathrooms: 2.5
Living Space : 2966 sqf
Cost (USD/sq. ft.): $250/sqf

Builder: Bob Dykins, Glastonbury Housesmiths
Architect/designer: Russell Campaigne, CK Architects
Engineer: E2 Engineers

Construction

Foundation: Poured concrete (50% slag) basement with 10-in. walls insulated with 2 3/8-in. exterior semi-rigid fiberglass board plus 2-in. interior rigid 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. foam (R-20 total);
Above-grade walls: 2x6, 16 in. o.c.; blown-in fiberglass (R-21)
Windows: double-pane, 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; U-factorMeasure of the heat conducted through a given product or material—the number of British thermal units (Btus) of heat that move through a square foot of the material in one hour for every 1 degree Fahrenheit difference in temperature across the material (Btu/ft2°F hr). U-factor is the inverse of R-value. = .31 (R-3.2)
Roof: 2x10 and 2x12 rafters, 16 in. o.c.; vented; blown-in fiberglass insulation; cathedral ceiling R-30, flat ceiling R-43
Garage: detached

Energy

Heating/cooling: ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures. (Water Furnace; EEREnergy-efficiency rating or energy-efficiency ratio. As most commonly used, EER is the operating efficiency of a room air conditioner, measured in Btus of cooling output divided by the power consumption in watt-hours; the higher the EER, the greater the efficiency. 30, COPEnergy-efficiency measurement of heating, cooling, and refrigeration appliances. COP is the ratio of useful energy output (heating or cooling) to the amount of energy put in, e.g., a heat pump with a COP of 10 puts out 10 times more energy than it uses. A higher COP indicates a more efficient device . COP is equal to the energy efficiency ratio (EER) divided by 3.415. 5) with horizontal ground loop
Water heating: Desuperheater with natural-gas backup
Annual energy use: 22.5 MMBtu

Photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. system: 3.25 kW; cost, $12,500 after rebates

  • Ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures.
  • ERV(ERV). The part of a balanced ventilation system that captures water vapor and heat from one airstream to condition another. In cold climates, water vapor captured from the outgoing airstream by ERVs can humidify incoming air. In hot-humid climates, ERVs can help maintain (but not reduce) the interior relative humidity as outside air is conditioned by the ERV. (Venmar)
  • Southern exposure and window layout provide 100% 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.
  • CFLCompact fluorescent lamp. Fluorescent lightbulb in which the tube is folded or twisted into a spiral to concentrate the light output. CFLs are typically three to four times as efficient as incandescent lightbulbs, and last eight to ten times as long. CFLs combine the efficiency of fluorescent light with the convenience of an Edison or screw-in base, and new types have been developed that better mimic the light quality of incandescents. Not all CFLs can be dimmed, and frequent on-off cycling can shorten their life. Concerns have been raised over the mercury content of CFLs, and though they have been deemed safe, proper recycling and disposal is encouraged. lighting in most fixtures
  • Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. appliances
  • Spray-foam air sealing before fiberglass insulation install

Water Efficiency

  • Low-flow sink faucets and showerheads
  • Drought-tolerant landscaping

Indoor Air Quality

  • MERV 8 air filtration
  • Central vacuum exhausted to exterior
  • Prefinished hardwood floors
  • 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. finishes
  • Low-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." composite-wood products

Green Materials and Resource Efficiency

  • 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.
  • Job-site recycling and ordering efficiency
  • Prefinished bamboo flooring
  • Composite doors and trim with recycled content

Certification

LEED for HomesLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. score (points earned/available): gold (80.5/130)
HERSIndex or scoring system for energy efficiency established by the Residential Energy Services Network (RESNET) that compares a given home to a Home Energy Rating System (HERS) Reference Home based on the 2006 International Energy Conservation Code. A home matching the reference home has a HERS Index of 100. The lower a home’s HERS Index, the more energy efficient it is. A typical existing home has a HERS Index of 130; a net zero energy home has a HERS Index of 0. Older versions of the HERS index were based on a scale that was largely just the opposite in structure--a HERS rating of 100 represented a net zero energy home, while the reference home had a score of 80. There are issues that complicate converting old to new or new to old scores, but the basic formula is: New HERS index = (100 - Old HERS score) * 5. Index (new rating system): 33

An Efficient Design and a Carefully Detailed Envelope Add up to Big Energy Savings

Craftsman bungalows are celebrated for being comfortable, practical and carefully crafted from local natural materials. This LEED Gold home in South Glastonbury, Connecticut, incorporates all of these qualities and more. To meet the homeowners' goal of creating an enjoyable and economical place to retire, CK Architects penned an attractive, efficient, and adaptable plan. A meticulously detailed building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials., a discretely mounted photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. array, and a ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures. keep the home affordable.

Let nature work for you
Beneficial natural conditions paired with good design choices helped maximize the project's sustainable features. An L-shaped house plan and a central screened porch let cooling breezes pass right through the house. An existing clearing made it easy to install the horizontal heat-pump loop and then cover it with a meadow of wildflowers. The landscaped portions of the site contain large beds of noninvasive, drought-tolerant plants, minimizing the need for irrigation and yard work.

Designed for easy living
Farmed white cedar shingles, fiber-cement siding, and cellular PVC trim ensure that the home’s exterior is low-maintenance and durable. CK Architects left the core living area open with plenty of south-facing windows, creating a bright, functional, and efficient space. Less frequently used, the guest rooms are deliberately isolated from the rest of the house, allowing John and Karen to reduce their heating demands when visitors aren't around.

Early actions pay off
The build team's commitment to environmental responsibility made joining the LEED for HomesLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. pilot program an easy decision. Doing this early in the process guided smart choices on everything from initial site preparations to interior finishes. Architect Russell Campaigne estimated that the green building methods added about a 5% premium over a comparable home built to code. With utility bills for the first year averaging less than $100 a month (pretty good considering Connecticut has some of the highest electric rates in the country), it seems that the investment is paying off.

Lessons Learned

Russell Campaigne referred to Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. guidelines when planning the insulation and air sealing for the house. Although the blown and batt fiberglass tested and ultimately performed very well, sprayed-in-place foam would have definitely been easier to install. After describing the difficulty in detailing the fiberglass correctly, Russell commented, "the contractor would have been happy to pay the extra cost of the foam."

He also found that the screened breezeway performed better than expected. Shade trees and the funnel shape of the house made it much cooler in summer and there was plenty of solar gain to help break the chill in the early months of spring.

Builder Bob Dykins' take on green building is that there needs to be more focus on methods that foster durability. On this project, planning siding laps to fall at the tops of windows, using strips of tarpaper as additional sill flashing over the siding below, and thoroughly air sealing below wall plates and around openings were a few simple steps that will make a long-term difference in the home's performance.


Rob Wotzak is assistant editor at GreenBuildingAdvisor.com

Tags: , , , , , , , ,

Image Credits:

  1. Russell Campaigne
  2. Olson Photographic
1.
Mon, 01/19/2009 - 11:50

If the HERS score is
by John Brooks

If the HERS score is 33...doesn't that mean that it will use 67% less energy than the comparable built to code "reference home"?
Where does the 75% lower utility bill come from?


2.
Mon, 01/19/2009 - 11:58

Another reason that it may be
by John Brooks

Another reason that it may be misleading to claim 75% reduction in utility bills....The more efficient homes pay an additional utility dollar cost per unit penalty when you average in the base fees.
In other words even if you use 67% less energy..your bill will not be 67% less...you still have to add the base fees.


3.
Mon, 01/19/2009 - 18:42

I like the Architecture, The
by John Brooks

I like the Architecture, The detached garage and the careful use of windows.


4.
Tue, 01/20/2009 - 10:53

Clarification of energy savings claims
by Rob Wotzak

John, you have a good point. The case study stated that there was a 75% energy savings over a comparable home. The reason that there might have been a difference between this number and the HERS score is that the HERS rating is a theoretical number whereas the 75% number was based on more than one year of actual energy bills. The flaw is that I did not present clear data for what represents the average home. I am editing the text to more clearly represent the data that we do have for this house. Thanks for your input.


5.
Fri, 02/06/2009 - 18:20

$250/Sf
by debra lombard

Is $250/SF for almost 3000Sf ($741,000) really sustainable?? CAn the average person in CT afford to live there?


6.
Fri, 02/27/2009 - 12:38

framing techniques
by tim eberhardt

is there a reason why you chose to space the studs 16" O.C as opposed to 24" ? also, is using a thicker foundation more efficient in costs and energy use?


Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!