The Bunker House of Tofte, Minnesota.

The Bunker House of Tofte, Minnesota.

*Adapted from a BASF case study .

Located in Tofte, Minnesota, the Bunker House is a single-family high-performance home. This 3,120 sq. ft space was completed in August of 2020 and built by Taiga Design Build. The Bunker House was constructed with structural insulated panels (SIPs) [manufactured by Energy Panel Structures] to reap the benefits of a quicker build, ease of installation, air tightness, lower utility costs, and needing less sealing than conventional framing. As the home sits on Lake Superior’s North Shore, energy efficiency was an important factor.

SIP wall thickness and core material: 6″ Neopor    R30
SIP roof thickness and core material: 10″ Neopor R-50

Additionally, to being constructed with SIPs, the house is supported by large exterior glu-lam beams, has large Southern windows for natural heating in the winter, and large trees which allow extra cooling in the summer. It’s HVAC system is consisted of Dual fuel, in-floor, radiant heat. The primary heat source for the hydronic fluid is an interruptible Slant Fin Monitron electric boiler (100% efficient). The secondary source is a Navien propane boiler (95% efficient) which also serves as a secondary source of domestic hot water. EcoTech air exchanger provides outside air.

HERS Index: Estimated 28

Blower door test results: 0.89 ACH50

This SIPs high-performance home is set to weather the harsh north winds well. Surrounded with breathtaking views, it features below ground wine storage and a large walk out deck from the kitchen.

Meet the Next Generation of Insulation

BASF Neopor Plus GPS a graphite polystyrene (GPS) rigid foam insulation that gives maximum efficiency, cost-effectiveness and sustainability on construction projects. Grey Neopor Plus GPS is comprised of many small pockets of air within a polymer matrix containing graphite. The graphite reflects radiant heat energy like a mirror, increasing the material’s resistance to the flow of heat, or R-value.

Learn more about this smart insulation here.

Zero Energy Ready Homes: What Does It Mean to Be “Future Ready”?

Zero Energy Ready Homes: What Does It Mean to Be “Future Ready”?

When you’re searching for a home, new doesn’t always mean new – even when you’re buying a home that was just built. Some new homes feature more energy efficient appliances and components than others, so how can potential homebuyers ensure they’re getting the latest and greatest offerings in building energy performance that new homes can provide today?

The answer is Zero Energy Ready Homes. That’s because a Zero Energy Ready Home must meet multiple layers of requirements, related not only to energy performance, but also indoor air quality and building construction. Watch this video to learn more about what a Zero Energy Ready Home can do for you.

An aerial view of the U.S. DOE 2020 Zero Energy Ready Home Housing Innovation Award winning home “La Pedrera Net Zero Residence” by Bellingham Bay Builders in Friday Harbor, WA. This home features a high-performance insulation system and advanced energy-efficient appliances and lighting systems that keep its entire monthly energy bill around $30, saving these homeowners about $2,000 every year compared to the energy performance of more typical newly built home.

A DOE Zero Energy Ready Home meets all the criteria found in the DOE Zero Energy Ready Home National Program Requirements. DOE Zero Energy Ready Homes are verified by a qualified third-party and are at least 40-50% more energy efficient than a typical new home. This generally corresponds to a Home Energy Rating System (HERS) Index Score in the low to mid-50s, depending on the home’s size and climate zone.

Buyers who choose a Zero Energy Ready Home know that their new home not only includes highly energy-efficient technologies and systems, but also incorporates best construction practices, and is certified by three independent programs.

Innovation #1: Maximum Protection Construction, featuring industry-leading best practices for wall, roof, and foundation assemblies:

  • Above-code insulation provides a thick thermal blanket for a cozy interior year-round.
  • Comprehensive draft sealing blocks dust, moisture, pollen, and pests from getting through thousands of feet of cracks and dozens of penetrations commonly found in home construction.
  • Advanced window technology minimizes heat loss in the winter and unwanted heat gain in the summer to help ensure comfort, quiet, and low utility bills.
  • Top-to-bottom moisture barrier effectively drains water from roofs, walls, and foundations so it can’t find its way inside where it can cause dry rot, mold, and odor problems.

Innovation #2: Advanced Technology throughout each home that works and lasts better:

  • High-performance heating and cooling provides total comfort with expertly installed and sized systems to industry best practices.
  • High-efficiency ENERGY STAR appliances, lighting, and fans save money with rigorous requirements for meeting and exceeding performance expectations.
  • Solar-ready construction allows homes without solar panels to add them in the future with minimal disruption and thousands of dollars in savings.

Innovation #3: Certified Performance independently verified for three high-performance programs:

  • ENERGY STAR-Certified Home ensures a strong foundation of above-code efficiency and performance measures.
  • Indoor airPlus certification ensures a comprehensive package of indoor air quality measures that can help protect the health of each household.
  • Zero Energy Ready Home certification further optimizes performance and efficiency so all or most annual energy consumption can be offset with renewable energy.

If you are a homebuyer, you want all these innovations. Their value is timeless: you’ll live better, and your utility savings can add up to tens of thousands of dollars over a 30-year mortgage.

A view from the La Pedrera Net Zero Residence’s living room. You can take a virtual tour of this award-winning home and others that DOE has recognized with its annual Housing Innovation Awards in the DOE Tour of Zero.

During this year’s Net Zero Buildings Week, the Buildings Technologies Office is recognizing the growing demand for net zero technologies and practices by highlighting the work that DOE and its partners are doing to achieve a more energy efficient future.


Learn more about DOE’s Zero Energy Ready Home program here.