New infill construction

Fox Family Passive House & ADU

Project Description

Five years ago, the Fox Family purchased a single 25-foot wide vacant lot in central Denver, envisioning a future where they could build both a home and a family. Today, the family comprises two adults, two young children, a dog, and a cat. With one parent working from home and frequent visits from friends and family, the time had come to transform their dream into reality.

The Fox Family's vision for their new home was rooted in responsibility and sustainability. They sought a design that would harmonize with the neighborhood, foster a healthy indoor environment for their children, and minimize environmental impact. Additionally, they required a detached apartment to accommodate visiting guests, provide potential rental income, or serve as a future living space for an aging parent—all within their standard 25’x125’ urban Denver lot.

To achieve this vision, the Fox Family enlisted the expertise of Old Alt New. Together, they embraced the principles of Passive House design, focusing on high performance and low carbon impact. The result is a home that not only meets but exceeds the family's needs and environmental goals.

Project Basics

Location: Denver, Colorado, USA

Project Type: New Single-Family House w/ Detached Garage & ADU

Size: House: 2,227 gross square feet, Garage: 370 gsf, ADU: 421 gsf

Project Status: Architectural Design - Complete

Project Team

Architect: Old Alt New

  • The Fox Family House, viewed from the street, showcases a no-water xeriscape tree lawn and a low-water native grass front yard. These sustainable landscaping choices minimize yard work while supporting pollinating birds and insects.

  • The home's design fits in with its surroundings. A projecting balcony and recessed front door define a protected entry. The balcony is an ideal spot to relax and enjoy a sunset over the front range. An eco-friendly garden adds natural beauty to the neighborhood.

  • The Fox Family house locates the kitchen, dining, and living rooms within the same shared space - immediately adjacent to the private backyard for grilling and entertaining. The family values privacy, but when it comes to the heart of the home, the family wanted a shared space to connect.

  • The upstairs hallway is designed to enhance privacy between the bedrooms while featuring cozy nooks for reading and abundant storage.

    Modest in square footage, the master bedroom efficiently incorporates four distinct areas: a tranquil sleeping space, an en suite bathroom, a walk-through closet with built-in wardrobes and desk, and a west-facing balcony.

  • In contrast to the public-facing front yard, the Fox Family's private backyard is designed for year-round enjoyment. It features protection from the summer sun, an entry awning for winter snow, and zero-maintenance pavers and gravel.

  • The garage and ADU include a wood-clad vertical growing wall, enhancing both indoor and outdoor living spaces with plants while ensuring privacy for ADU residents.

  • The Fox Family requested a one-car garage for their vehicle and outdoor gear, along with an accessory dwelling unit (ADU) for hosting guests, in-laws, or use as a home office or rental unit for supplemental income.

    This combined garage and ADU maximizes Denver's zoning allowances and bulk-plane exceptions. A standout feature is the large entry balcony, providing the ADU with its own private outdoor space.

  • An outdoor stair, protected from the elements, leads to the east-facing private balcony and accessory dwelling unit. The fenced south side yard is dedicated to the ADU; the north side is open to the house for garage and alley access.

A house that is proud to be called ‘home’

The Fox Family's new home is not just a dwelling but a manifestation of their values and aspirations. It embodies thoughtful design, sustainable living, and the harmonious integration of family needs with environmental stewardship.

Beyond sustainability, the Family’s top priorities included:

  1. A house that makes living easier.

  2. Lots of storage.

  3. Quiet & private bedrooms - including guests

The right fit

Neighborhood Integration: The architectural design respects the existing single-family neighborhood aesthetics while incorporating modern elements, ensuring the home is both a good neighbor and a standout in the community.

Detached Apartment: A versatile detached apartment above the garage offers flexible use as a guest suite, rental unit, or future living space for an aging parent, maximizing the utility of the urban lot.

Drawings

Roof Plan

Second Floor Plan

First Floor Plan

Longitudinal Section

Cross Section through Garage & ADU

Cross Section through House

Space Key

  1. Front Yard

  2. Front Entry

  3. Office / Guest Room

  4. Bathroom

  5. Landry Room

  6. Hall

  7. Utility Closet

  8. Stair

  9. Heat Pump Location

  10. Kitchen

  11. Dining Room

  12. Living Room

  13. Pantry / Rear Entry

  14. Backyard

  15. Garage

  16. Mater Bedroom

  17. Walk-Thru Closet

  18. Balcony

  19. Master Bathroom

  20. Bedroom

Passive House Performance Characteristics:

  1. Passive House Certification: The design prioritizes energy efficiency through superior insulation, airtight construction, and high-performance windows, ensuring minimal energy loss and exceptional indoor air quality.

  2. Rooftop Solar Panels: Integrating a rooftop solar array allows the home to generate more electricity than it consumes, aiming for a net-positive energy footprint.

  3. Healthy Indoor Environment: Ventilation systems with heat recovery provide continuous fresh air, significantly reducing allergens and pollutants, creating a healthier living space for the children and the entire family.

  4. Sustainable Materials: The selection of sustainable, locally-sourced, and recyclable materials throughout the construction process reflects the Fox Family's commitment to reducing their environmental footprint.

  5. Longevity and Durability: Unlike most new houses built today, this house is designed to last into the next century. It aspires to be a beautiful and historic house - 100 years from now.

Envelope performance notes:

  • 0.6 blower door score @ ACH50

    • exterior: Zip sheathing air barrier, taped and sealed

    • interior: Intello+ smart vapor retarder and air barrier

  • R-44 Wall Assembly

    • double stud wall w/ dense pack cellulose

  • R-58 Roof Assembly

    • deep TJIs w/ dense pack cellulose

  • R-20 Concrete-Fee Floor Slab Assembly

    • double plywood deck w/ rigid mineral wool board

  • triple pane glazing at windows and doors

    • Phius-certified Alpen windows and doors

  • Rainscreen wall construction

  • Ventilated ‘cold’ roof deck construction

Typical Wall-to-Eave Detail

Active systems performance notes:

  • fully electrified systems and appliances, no gas

  • high-efficiency cold climate heat pump

    • year-round heating and cooling

    • combination ducted and mini-split distribution

  • Energy Recovery Ventilator (ERV)

    • an absolute must for well-built buildings

    • balanced supply and exhaust levels

    • deliberate fresh air intake, filtered of allergens and pollutants, pre-conditioned for temperature and humidity by the exhaust

  • heat pump water heater

    • ultra-compact distribution system to maximize heat conservation and reduce hot water wait times

  • Roof-top photovoltaic solar panel array

    • optimal orientation facing south

    • sized to exceed on-site requirements

    • EV charging station in the garage

Concept Design:

Space Adjacency Diagram

Concept rendering of the house from the street.

Early Stages Site & Massing Organization

Concept rendering of the ADU & garage from the alley.

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