2015 Challenge Participant:

Lehto Design/Build - Kallen Residence

Applicants: Lowel Kallen, Nick Lehto

Project Address: 464 Senexet Road, Woodstock, CT 06281

Bdrms./Sq. Footage: 4 BD - 6388 sq ft

Project Overview Project Specifications Project Team Project Photos
The Lehto Design/Build - Kallen Residence project in Woodstock, CT.

General Project Overview:

Lowell and Patricia Kallen have had long standing commitments to the environment, one of us having been accused of "conspicuous under consumption" in college more than a half century ago.  We have been strong adherents to the "refuse, reduce, reuse, and recycle" principles of "going green" as well as the increasing awareness of the importance of sustainability.  Through the years our commitment has increased as there have been more and more concern about decreasing natural resources, loss of habitat, global warming, and concerns about the dangers of nuclear energy.  When we decided to relocate back to Connecticut to be near our children and grandchildren it therefore seemed natural to plan as ecologically a friendly home as we could design.  Our love for our children and grandchildren was a further impetus to try to go as "green" as possible to help preserve the earth and resources for them and their future generations.  To paraphrase an old saying, we did not inherit the earth from our parents; we are borrowing it from our children.

We found a lovely and suitable location in Woodstock.  The home is situated so as to have attractive views to the east and west as well as a large southern exposure to provide for solar power, a 12.5 kilowatt system, which will eliminate the need for net power and contribute to the home being a "net zero" home.  A state of the art geothermal system with two wells was installed to achieve the maximum efficiency in heating and cooling that we could find.  Framing was done using wood rather than steel to utilize natural and renewable resources as well as resources that consume less energy to produce.  Exterior walls were constructed to be one foot deep to permit more effective insulation.  Insulation was chosen to be cellulose rather than fiberglass, again to utilize the most environmentally friendly resources and maximize the use of recycled materials as well as to be able to achieve "super insulation" to minimize energy use.  Landscaping will be designed to be drought resistant as well as to minimize maintenance requirements or the need for environmentally unfriendly chemicals.  Native plants indigenous to the region will be emphasized.

Orientation and Envelope: (Windows, Insulation, Framing)

  • Orientation:  The home is located on top of a hill overlooking a meadow below.  Due to the view, the home is oriented towards the south-west.  This allows its occupants to take advantage of passive solar heat gains, while still allowing them to enjoy the beautiful view.
  • Walls: Double stud walls framed 12” deep.  The cavity is filled with dense pack cellulose to achieve an R-Value of 45.
  • Roof: R70 Loose fill cellulose                      
  • Foundation: R26  2” Closed cell spray foam with r13 Fiberglass batts.
  • Slab:  R20 – 4” XPS insulation
  • Windows:  This home features high performance triple pane windows with R-Values ranging from R-5 – R6. 
  • Airtightness:  Great means will be taken to ensure that the home will be built air tight.  The goal for the house is to have a blower door reading of .5ACH50. 

Heating, Cooling, and Hot Water:

  • Waterfurnace Series 7 – Variable capacity geothermal heating and cooling system.   This unit is the most efficient on the market and has the ability to operate at a wide range of outputs to meet your specific demands.
  • Domestic hot water will be supplied by two systems.  The first system will be desuperheater that uses waste heat from the geothermal system to pre-heat the water while the remaining needs will be provided by an on-demand water heater.


  • This home will utilize a high efficiency Venmar ERV, which will simultaneously remove stale air from the house, and supply fresh filtered air.


  • To minimize the energy demands, all lighting will either be LED or CFL.  All appliances will also be Energy Star rated.


  • A 12.5kw Photovoltaic system will be installed to offset all of the home's annual energy usage.
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