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Rocky Neck Village: The Challenges and Benefits of Passive Housing

East Lyme, CT

Exterior View

Off to a rocky start, when it was proposed in 2013 because of its location in a light industrial zone with possible chemical exposure, Rocky Neck Village, located in East Lyme, CT is now completed. Built primarily in 2021, this residential affordable housing community has 50 3-bedroom 2-story townhouses and 6 ADA-compliant one-story townhouses.

The residents of Rocky Neck Village are now the beneficiaries of the unusual aesthetic of the complex which was designed to blend in with the East Lyme landscape. Known for its exceptional school system, quality of life and wide array of recreational opportunities, this picturesque town is known as one of the best places to live in Connecticut.

The new residents are also the recipients of affordable housing and the prospect of a lower electric bill. That is because this property was designed to passive house standards.

“The roots of passive house trace back to the energy crisis of the 70s though at that time we did not understand the building science," explained Peter Harding, Environmental and Energy Expert, Vice President, MacGrann Associates who was a partner in the project. “The passive house movement gained momentum back in early 2000 in Europe and has been quietly gathering strength in the US as well.”

Passive house may cost more to build but they are healthier, more affordable, and more durable.

The Benefits of Passive House Standards

  • Maximum energy efficiency: Passive house is the most stringent residential housing code and is 90% more energy than current typical buildings, even those which are energy-star certified.

  • Lower carbon footprint: Passive housing is a voluntary standard for energy efficiency which reduces the carbon footprint.

  • Proficient energy recovery ventilation: Well-insulated and airtight, passive house standards reduce the heating and cooling loads and allow for the use of a balanced ventilation system. It brings in fresh air from the outside and takes stale air from inside and either preheats or precools the incoming air with the energy of the outgoing air. This process is referred to as energy recovery ventilation.

  • Reduces electric bills for residents: Passive Housing results in an ultra-low energy building that requires little energy to achieve a comfortable temperature thereby reducing the electric bill for the residents. Electric bills were further reduced by the addition of solar panels which were installed on the roof, allowing for on third of the energy to be powered by sunlight.

  • Provides rebates to developers: Eversource, New England's largest energy provider, offers programs for building more energy-efficient homes and that enabled the developers to receive energy rebates. The rebates help offset the extra costs associated with the passive house standards.

  • Promotes a healthier air quality: Good ventilation is important for promoting a healthy indoor environment. Passive Housing can prevent outdoor air pollution from entering and regularly filters indoor air which greatly reduces the chances of things like mold.

While there are a multitude of benefits, building a complex to meet passive housing code standards can be challenging.

“The whole project was a challenge. It was the first passive house project we did with LaRosa so it was a learning experience for both of us. To start it was exciting and to finish it was even more exciting.”

-- David P. Pernal, Senior Project Manager, LaRosa Building Group

Here are some of the challenges of meeting passive housing code standards:

Airtightness requirements: The main challenge was meeting the stringent requirement for airtightness. While the building code has a certain threshold to qualify as a passive house, the threshold for passive housing is much greater. We used a process called AeroBarrier which uses a blower door test to identify any leakiness and then blows sealant through nozzles to fill in the gaps. That was a useful tool to meet the air tightness requirements.

Insulation requirements: The insulation requirements were also more stringent. In some cases, we had eight inches of insulation under the slabs of the house where we would have normally put two inches. In addition to the added expense, the contractors had to be extra careful in laying the slabs.

Construction sequence: The project had an unusual architectural design, with many jogs and inside and outside corners, to blend into the Lyme community. These corners made meeting passive housing standards more complex and we had to modify the construction sequence. In most housing projects, you frame and put on the exterior sheeting. To meet the passive housing standards, we have to complete 90 percent of the framing, add the sheeting and then complete the framing.

Covid challenge: The construction took place during Covid so the usual supply chain issue and increased cost issues were experienced.

Increased costs: The passive house building is costly, not just due to the cost of the materials but also the additional labor required. You have to build, stop and then build some more, which is not the general way we proceed in our construction projects. There were also additional costs due to the addition of the Aero barrier which was not in the original projections. The configuration caused so many challenges so the owner decided it was well worth the cost.

Learning curve for residents: The doors windows, and ventilation system need to work together to achieve the goals which necessitated a learning curve for tenants. All tenants had to be taught what to do and what not to do maximize the energy efficiency of the building.

"Our expertise in creating passive homes has been increasing with each project. With that growth, we are able to train our partner contractors and subcontractors, thereby minimizing the challenges and increasing the possibilities for passive homes to become a standard in the industry.”

-- James LaRosa, Chief Executive Officer, LaRosa Groups

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