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MREA Gives Back: Whitehall Net-Zero Energy Affordable Housing Project

MREA Gives Back: Whitehall Net-Zero Energy Affordable Housing Project

December 2020 marked the 20th anniversary of MREA's founding. Two decades ago, a small group of renewable energy installers, advocates, and supporters formalized what would grow into the education and advocacy organization that we are today. We are grateful for the immense support from our communities and combined efforts driving the development of renewable energy in Montana!

In continuing our mission of expanding renewables to all Montana citizens, MREA is celebrating our 20th year by 'giving back' and supporting clean energy projects that impact the lives of our broader communities. While we can't grant funds ourselves, our goal is to bolster partner projects by raising awareness, funneling financial support, and highlighting the socio-economic benefits of such projects. We hope you will consider supporting these projects to help make them a reality.

Whitehall’s Mountain Horizons Solar Subdivision:
Net-Zero Energy Affordable Housing

The National Affordable Housing Network (NAHN) has developed cost-effective Net Zero Energy (NZE) single-family homes powered by solar electric (PV) systems in Montana. A NZE building produces as much power from renewable energy as it uses on an annual basis.

Solar on the roof of a home

The new home models combine advanced energy efficiency and PV systems sized and based on NAHN’s NZE-Ready standard package house plan, which is optimized based on simulation and performance monitoring. NZE- “Ready” means a building is designed for a renewable energy system to be installed efficiently and cost-effectively at a later date.

These homes are comfortable, safe, and resilient. Proper building orientation provides passive solar heat gains, and heat recovery ventilation keeps the indoor air free of pollutant build-up while reclaiming 70% or more of the space heat generated by the home. The lack of indoor pollutants from building materials achieves clean air standards needed by those with breathing conditions.

Walls are made of structural insulated panels (SIPs) due to their structural strength and storm and water damage resistance. The reduced heat loss and warmer indoor surface temperature of the homes create a comfortable environment where the interior mass of the sheetrock and insulated slab-on-grade floor make for a steady indoor temperature and less human body energy loss to cold surfaces. The construction sequence ensures that air tightness features are accurately built into the design for long-term performance. It is notable that NAHN conducted a large number of detailed performance studies in the 1980s and used the resulting high-performance design for homes starting in the1990s.

Solar on one-car garage

PV arrays are located on either the home or garage roof. Solar production covers all energy loads including an interior heat-pump water heater, space heating, appliances, and lighting for homes with 1,300 SF. Combined with other climate-ready features, the homes are ready for storm conditions in the future. Learn more at: Whitehall Mountain Horizons Subdivision: National Affordable Housing Network (

Amount of funding needed

$17,000 is needed for a 7 kW PV system for one of the five NZE-Ready homes. The NZE-Ready homes currently have no secured funding for PV systems. The first four homes built received Northwestern Energy USB grants, and homeowners used the Montana DEQ low-interest loan program to borrow funds to pay the remaining balance on their PV systems.

The cost of the homes is similar to or less than conventional homes, and with federal Self-Help Programs or Habitat partnership they are already affordable to Montanans with low or very low incomes. In the case of Whitehall, the Self-Help Program’s NZE homes average under $190,000 including land. Based on the current price of energy, the energy package’s cost is recovered in under 10 years. With diligence, net zero operation with a 7 kW PV system could also provide 2,500 kWh for an electric vehicle - enough to drive locally for 8,500 miles.

Project Beneficiaries

Twenty people currently live in the subdivision. Tax-deductible donations made directly to NAHN will go toward purchase and installation of a 7 kW PV system on one of the five NZE-Ready homes helping folks who make 80% or less of the area’s median income level afford the upfront investment in NZE.

Additional Information

The first four NZE homes built are complete with PV systems. Five additional NZE-Ready homes are built, but are awaiting PV systems. In the future, at least 25 additional NZE or NZE-Ready homes will be built in the subdivision where lots are laid out to maximize solar gain.

Getting Involved and Supporting the Project

Please contact Barbara Miller, Director of the National Affordable Housing Network, if you would like to assist in supporting this project:

Barbara Miller, Director
National Affordable Housing Network
PO Box 632, Butte, MT 59703
tel: (406) 782-8579; fax: (406) 782-5539

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