PHIUS Certified Builder
Phius Certified Builders are construction professionals trained to meet the challenges of building to the rigorous Phius passive building standard.
Frequently Asked Questions
Who is PHIUS?
PHIUS stands for the Passive House Institute US, a nonprofit organization dedicated to advancing energy-efficient building standards in the United States. PHIUS develops climate-specific guidelines, provides certification for homes and buildings, and trains professionals to ensure that passive projects perform at the highest level of comfort, energy savings, and durability. They adapt the Passive House standard to U.S. climates, ensuring that each building achieves optimal efficiency and comfort no matter where it’s located. Does it cost a lot more to build a passive building compared to a conventional equivalent?
Does it cost more to build a passive house compared to a conventional home?
Building a Passive House typically costs about 5–10% more than a standard home. While this is a modest upfront increase, the long-term savings are substantial. Passive homes are designed to use up to 90% less energy for heating and cooling than conventional homes, meaning utility bills are drastically lower year after year. Over the life of the home, the energy savings often more than offset the initial cost difference, making Passive House construction a smart investment in comfort, durability, and long-term financial savings.
What is it like to live in a passive house?
Passive houses are extremely comfortable year-round. There are no drafts, indoor temperatures are very consistent, and balanced mechanical ventilation ensures superb indoor air quality. Yes, passive house owners can open doors and windows just like in any conventional home, but the design ensures comfort even when they remain closed.
Passive buildings are airtight – what about moisture and mold problems?
In a typical standard-built home, drafts, temperature swings, and uneven ventilation can create hidden moisture pockets, leading to mold and structural problems over time. In contrast, a PHIUS-certified Passive House actively manages airflow and moisture, pairing airtight construction with super-insulation and carefully controlled mechanical ventilation. This ensures superior air quality, consistent indoor temperatures, and a home that is resistant to mold and moisture issues.
Do passive buildings all have to look the same?
Not at all! A Passive House can be built in any style you love—from classic farmhouses and charming cabins to ranch-style homes. You can even use your existing favorite plans or custom designs, and we’ll adapt them to meet PHIUS standards. Passive design is all about comfort, energy efficiency, and durability, not forcing a particular look. Your home can be beautiful, unique, and built to last, all while saving energy and keeping you comfortable year-round.
Better For You & Your Family
Applying Passive House Principles
As a PHIUS Certified Builder, we bring Passive House principles to life with craftsmanship that blends comfort, efficiency, and durability. Every project starts with a focus on the building envelope—sealing and insulating with precision to eliminate drafts, reduce energy loss, and create a home that stays comfortable year-round. Through expert detailing and testing, we make sure your home meets the rigorous airtightness and performance standards set by PHIUS.
High-performance windows and doors are installed with care to maximize natural light, capture the sun’s warmth in winter, and prevent overheating in summer. Paired with advanced ventilation systems, this approach delivers fresh, healthy air throughout your home while maintaining exceptional energy efficiency. The result is a living environment that feels consistently comfortable, quiet, and clean.
Because PHIUS standards are tailored to local climates, we adapt each design to meet the unique conditions of your region. This means your home achieves the highest level of performance possible without unnecessary cost. From the foundation to the final details, we combine proven building science with hands-on expertise to ensure your home is built to last, delivering lower energy bills, greater comfort, and peace of mind for decades to come.
Better For You & Your Family
Applying Passive House Principles
As a PHIUS Certified Builder, we bring Passive House principles to life with craftsmanship that blends comfort, efficiency, and durability. Every project starts with a focus on the building envelope—sealing and insulating with precision to eliminate drafts, reduce energy loss, and create a home that stays comfortable year-round. Through expert detailing and testing, we make sure your home meets the rigorous airtightness and performance standards set by PHIUS.
High-performance windows and doors are installed with care to maximize natural light, capture the sun’s warmth in winter, and prevent overheating in summer. Paired with advanced ventilation systems, this approach delivers fresh, healthy air throughout your home while maintaining exceptional energy efficiency. The result is a living environment that feels consistently comfortable, quiet, and clean.
Because PHIUS standards are tailored to local climates, we adapt each design to meet the unique conditions of your region. This means your home achieves the highest level of performance possible without unnecessary cost. From the foundation to the final details, we combine proven building science with hands-on expertise to ensure your home is built to last, delivering lower energy bills, greater comfort, and peace of mind for decades to come.
Frequently Asked Questions
Who is PHIUS?
PHIUS stands for the Passive House Institute US, a nonprofit organization dedicated to advancing energy-efficient building standards in the United States. PHIUS develops climate-specific guidelines, provides certification for homes and buildings, and trains professionals to ensure that passive projects perform at the highest level of comfort, energy savings, and durability. They adapt the Passive House standard to U.S. climates, ensuring that each building achieves optimal efficiency and comfort no matter where it’s located. Does it cost a lot more to build a passive building compared to a conventional equivalent?
Does it cost more to build a passive house compared to a conventional home?
Building a Passive House typically costs about 5–10% more than a standard home. While this is a modest upfront increase, the long-term savings are substantial. Passive homes are designed to use up to 90% less energy for heating and cooling than conventional homes, meaning utility bills are drastically lower year after year. Over the life of the home, the energy savings often more than offset the initial cost difference, making Passive House construction a smart investment in comfort, durability, and long-term financial savings.
What is it like to live in a passive house?
Passive houses are extremely comfortable year-round. There are no drafts, indoor temperatures are very consistent, and balanced mechanical ventilation ensures superb indoor air quality. Yes, passive house owners can open doors and windows just like in any conventional home, but the design ensures comfort even when they remain closed.
Passive buildings are airtight – what about moisture and mold problems?
In a typical standard-built home, drafts, temperature swings, and uneven ventilation can create hidden moisture pockets, leading to mold and structural problems over time. In contrast, a PHIUS-certified Passive House actively manages airflow and moisture, pairing airtight construction with super-insulation and carefully controlled mechanical ventilation. This ensures superior air quality, consistent indoor temperatures, and a home that is resistant to mold and moisture issues.
Do passive buildings all have to look the same?
Not at all! A Passive House can be built in any style you love—from classic farmhouses and charming cabins to ranch-style homes. You can even use your existing favorite plans or custom designs, and we’ll adapt them to meet PHIUS standards. Passive design is all about comfort, energy efficiency, and durability, not forcing a particular look. Your home can be beautiful, unique, and built to last, all while saving energy and keeping you comfortable year-round.
Grounded & Trustworthy, Yet Visionary
Why Choose Legacy Mountain Builders?
BUILDS THAT STAND THE TEST OF TIME.
Building or renovating a home is one of the biggest investments you’ll ever make, and choosing the right builder makes all the difference. A PHIUS Certified Builder like Legacy Mountain Builders is trained and tested to meet the highest standards in energy-efficient construction. This certification isn’t just a title—it’s proof that Legacy Mountain has the knowledge and 20+ years of hands-on expertise to deliver a home that’s healthier, more comfortable, and more cost-effective to own.
When you work with Legacy Mountain Builders, you’re choosing a company who understands every detail of high-performance construction, from airtight building envelopes to advanced ventilation systems. You’ll enjoy lower utility bills, better indoor air quality, and a home that stays comfortable in every season. Most importantly, you’ll have peace of mind knowing your home is built with proven methods that stand the test of time.
BEYOND PERFORMANCE BUILDS
Beyond performance, we focus on building with care, precision, and integrity. Our goal is to make the process as smooth as possible while delivering a home that exceeds your expectations. With Legacy Mountain Builders, you don’t just get a house—you get a lasting investment in comfort, sustainability, and quality.
Built On Trust
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