Net-Zero SIP Farmhouse Longmont CO

Location: Longmont, CO

Project Information

Project Type: Residential, > 3,000 sq. ft.
Manufacturer: Premier Building Systems
Builder: PG Arnold Construction
Design Professional: SH-6 Architecture +Design
Year Built: 2024

Performance

High Performance: Yes
HERS/EUI Index Score: -26
ACH50 - Blower Test Results: 1.64
kBtu/sq.ft./year: -7.3
CO2 lbs./sq.ft./year:

Awards/Certifications: DOE Zero Energy Ready Home, ENERGY STAR Certified, EPA Indoor AirPLUS

BEA: 2025 Building Excellence Award - High Performance Winner

The owners of Sundance Farms lived for 30+ years in a converted airplane hangar while running the 15 acre farm.

A Net-Zero Farmhouse for the Future: Sundance Farms

The owners of Sundance Farms, having lived for over three decades in a converted airplane hangar while operating their 15-acre farm, now reside in a high-performance, net-zero energy, all-electric farmstead. This passive solar residence seamlessly blends modern conveniences with unique features like a wool-dying workshop and a wool-spinning loft, all within a comfortable 3274 square feet of conditioned living space. An attached 1166 square foot garage completes the property.

SIP Specifications:

  • Wall: 6" EPS (House) / 4" EPS (Garage)
  • Roof: 12" EPS (House) / 10" EPS (Garage)

Prioritizing Sustainability and Longevity:

A key objective for the owners was to create a low-maintenance, all-electric home with a lifespan exceeding 100 years. The focus was on utilizing renewable energy sources and minimizing environmental impact. After careful evaluation of various construction methods, including straw bale, straw clay, earth blocks, and double wall framing, SIP construction emerged as the most suitable option, offering an optimal balance of embodied energy, maintainability, cost-effectiveness, and longevity.

SIPs: Enabling High-Performance Construction:

The utilization of SIPs facilitated a highly efficient construction process. An experienced framing crew, with additional on-site training to refine airtightness detailing, ensured precise installation and achieved a remarkable HERS rating of -26.

A Durable and Weather-Resistant Envelope:

To ensure the long-term durability of the SIPs, significant attention was paid to weather protection:

  • Extensive Overhangs: Large roof overhangs minimize solar heat gain during summer months while maximizing solar heat gain during winter.
  • Rainscreen System: A ventilated rainscreen wall assembly and a "cold roof" design create an air gap between the cladding and the SIPs, allowing for efficient moisture drainage and preventing moisture damage.
  • Foundation Details: Careful attention was paid to isolating the sills from potential moisture wicking from the ground.

High-Performance Features:

  • Energy Efficiency:
    • HERS: -26
    • ACH50: 1.64
    • Zero Energy Ready Home Certified
    • Energy Smart Certified
  • HVAC System:
    • Mitsubishi Heat Pump system with four strategically placed wall-mounted air handlers.
    • Panasonic Intelli-Balance ERV for fresh air ventilation and exhaust.
    • High-velocity low-speed (HVLS) ceiling fan in the great room.
    • Infrared cove heaters for supplemental heating.
  • High-Performance Envelope:
    • Triple-pane windows (U-value 0.14 average, SHGC 0.46 south-facing, SHGC 0.17 other aspects).
    • Optimized thermal mass concrete floor with embedded radiant tubing.
    • High-reflectivity metal roofing to minimize heat absorption.

Sustainable Practices:

  • Renewable Energy: An 18.8 kW solar array installed on the barn roof generates more than enough electricity to power the house and offset a significant portion of the farm's energy needs, including tools, machinery, and irrigation.
  • Indoor Air Quality:
    • GREENGUARD certified building materials.
    • Low-VOC paints, sealants, and adhesives.
    • FSC-certified millwork.
  • Material Reuse and Recycling:
    • Deconstruction and reuse of materials from the previous structure on the property.
    • Utilization of recycled content in building materials.

Conclusion:

The Sundance Farms residence exemplifies a commitment to sustainable building practices, creating a comfortable, energy-efficient, and long-lasting home for the future. This project demonstrates the successful integration of innovative design, high-performance building materials like SIPs, and renewable energy technologies to achieve a truly sustainable and comfortable living environment.

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