Construction Details

Montana has published the Montana Residential Energy Code Handbook . Blacktail Solar Homes will be guided by this handbook and will meet these requirements, and in many cases exceed them.

Information common to all construction phases can be found at Temperature Control


Phase IV of Blacktail Solar Homes is framed with 2x6 studs. All of the space between the studs is filled to a depth of 3 inches with Sprayed Polyurethane Foam (SPF) insulation.

Comparing stud/SPF construction with the Phase IV Structural Insulated Panel (SIP) construction gives some benefits and costs for each. SIPs have smaller vertical supports and thus transfer less heat to the outside from the inside. Stud/SPF is stronger and completely air tight so no heat is lost due to air flow. The insulation part of the R value will be acheiving R-20 or better with both systems.


Possibly the most important element in low input home design is the insulation. Insulation protects the investment in heating the space naturally by keeping the heat from escaping out of that heated space. Blacktail Solar Homes have R-50 in the space above the ceiling and R-20 or better in the walls. Crawl spaces under the houses are insulated to about R-15. All combined, these houses have excellent thermal characteristics.

The Blacktail Solar Homes insulation subcontractor has supplied a brochure describing in detail the product to be applied to Phase IV, Rhino Linings ThermalGuard cc2. In that brochure the advantages are described as follows:

  • ICC-ES Evaluation Report ESR-2100
  • Passes NFPA 286 without a prescriptive thermal barrier when used in conjunction with Fireshell F10E fire-protective coating
  • Class I fire rated
  • Appendix X compliant without any additional coatings
  • Low odor during application and produces no toxic vapors after application
  • Seals, insulates and minimizes uncontrolled air movement into a building envelope
  • Reduces energy consumption from heating and cooling
  • 245fa-blown, non-ozone depleting agent

Heating, Ventilation, and Air Conditioning (HVAC)

Passive solar heating is a big part of Blacktail Solar homes.

Electric heating is usually not the least expensive, but these homes are designed to require relatively little heating, and the solar panels will offset much of the cost. All external heat is electric.

Phase IV homes will be equiped with heat pump electric heaters that can also cool when that is what is needed.

HVAC systems process the air at a central location and the modulated air is distributed by way of air ducts to the various parts of the house. In addition to temperature control, the air in the home can be filtered to remove particles such as smoke or dust.

These systems pump heat from the outdoor air temperature into your home during the winter months and reverse this process to provide cooling in the summer. Air-source systems have the operating temperature range, between -13°F and 90°F (-25°C to 32°C).

Dillon Mt temperatures can drop below -13°F, and the systems at Blacktail Solar Homes Subdivision keep track of the outside temperature, and when it gets colder than the HVAC unit efficient range, the heat pump shuts of and an auxiliary resistive electric heater starts up to run during the peiod too cold for the heat pump to work efficiently.