FRISCO – Construction projects have a natural inverse relationship between affordability and sustainability.

If a developer wants to add energy-saving measures to a project, it will likely increase the cost. Finding a balance between these contradicting forces represents a challenge for developers. Affordable-housing projects – such as Peak One Neighborhood – make the task even more onerous, as a price ceiling is already in place. In the case of Peak One, the town set price points and sustainability metrics and tasked developer David O’Neil and his team have to meet both standards.

Frisco set a standard of 75 HERS (home energy rating system) for the houses being developed at Peak One. HERS are like miles per gallon for homes, except that a lower score is a better rating, according to High Country Conservation Center residential energy specialist Matt Wright.

The first house at Peak One was completed on schedule last week, and Wright audited the unit for HERS. It pulled an eye-catching 57 HERS.

“It’s a real credit to not only the detail that went into the design, but to (general contractor) Dan (McCrerey) and his crews during construction, and Matt and HC3’s help as we’re actually building it,” said project architect Matt Stais.

Wright and HC3 have played a critical role during the construction process to help McCrerey and his crews ensure the homes are sealed tight. During both the framing and insulation phases of construction, Wright provided pointers on how to seal thermal bypasses such as wiring and plumbing penetrations, and offered tips on best practices for installing fiberglass insulation.

The aim was to seal the unit up tight prior to the final audit that determined the house’s HERS score. For the audit, Wright brought in a blower door to pull air out of the house and change the pressure inside. From there he could determine where any leaks or drafts were and ultimately derive a HERS score.

The house turned out to be so airtight that a mechanical system for ventilation was necessary just to let the house breathe. Most homes depend on leaks and windows to regulate airflow, and while the mechanical system itself doesn’t represent a step toward energy efficiency, the well-insulated home that led to its requirement certainly does.

“Better to seal it tight and ventilate it right,” Wright said.

Now that Wright has gone through a few homes with McCrerey’s crew, his role is not as important during the construction phase.

“The longer we work with the builder, the more they’re going to be up to speed, and the less time they need me to be able to address these things,” said Wright.

Frisco senior planner Jocelyn Mills was pleased with the rating, as it represents a cost savings in a potentially energy consumptive portion of town. Peak One Neighborhood lies in the shadow of Peak One, where the sun sets earlier and radiant energy is not as abundant.

“It’s making affordable housing affordable to live in,” Mills said. The excellent HERS rating also means the house is eligible for rebates from Xcel energy.

Other houses in the neighborhood will be audited by Wright. Those associated with the project debated whether or not the duplex units would fare as well as the recently completed single-family unit. But with 69 units to go on the 12.68-acre site, everyone agreed that continued implementation of best building practices would improve HERS ratings for like units as the project develops.