HomeLink Magazine Summer 2017: Travelers Rest
Certified passive house promotes new goal for efficiency
By Suzie Romig
Photos: Ben Melnick, What If! Productions
Living five miles away from drilling rigs in northern Colorado, homeowner Danny Hoover sometimes awakes at night from the sounds of the extraction operations. Although his big-builder track home with 2 by 4 walls was constructed relatively recently in 2000, the house is not highly energy efficient and has already suffered a frozen and burst water pipe and water damage.
In contrast, when Hoover stays at this aunt’s nearby home located only one mile from the drilling rigs, he hears little from the outside environment, even during howling winds across the rural prairie setting. His aunt’s home, built in 2014, is four times the size of Hoover’s home but uses half the energy. That’s because the newer home is a certified passive house, one of only three certified single-family homes so far in Colorado and 107 certified in the country by the nonprofit Passive Haus Institute US.
“The house is definitely amazing,” said Hoover, who served as an on-site liaison while his aunt was overseas working for the U.S. Department of State. “I lived there when it was 17 below one time, and you could never even tell. It’s super, super efficient, and it really performs.”
A low maintenance, low energy-use passive house was exactly what homeowner Vicki Hutchinson (Hoover’s aunt) wanted after her long career with the government and state department. Having gutted and renovated homes herself in the past, she was an educated customer who had the patience to find the right passive house construction team to build on her 40-acre property purchased a decade ago.
Through her work on government facilities, Hutchinson knows the value of energy efficient buildings. From her travels, she values a restful, low-maintenance place to come back home to in Weld County, hence the name of her home, Traveler’s Rest.
“I am really pleased with my home,” said Hutchinson, speaking during an Internet phone call from her current placement in Erbil, Iraq. “It functions as I wanted and is so quiet and comfortable.”
Hutchinson selected builder Cody Farmer with MainStream Passive House Design-Build Practitioners in Berthoud after touring Farmer’s 3,600 square-foot Passivista project, which was later featured in the summer 2015 HomeLink edition. Just as the Passivista house near Broomfield received the Most Innovative Green Building Award 2014 from the Colorado Green Building Guild, Hutchinson’s house is also an award winner. Her home was named the guild’s Best New Green Home in Colorado in 2014.
According to Passive Haus Institute US, the German-inspired passive house concept comprises a set of design principles to attain a quantifiable and rigorous level of energy efficiency within a specific quantifiable comfort level. A passive building is designed and built in accordance with these five building-science principles:
- Employs continuous insulation throughout entire envelope without any thermal bridging
- Uses extremely airtight building envelope preventing infiltration of outside air and loss of conditioned air
- Employs high-performance windows and doors, typically triple-paned
- Uses some form of balanced heat and moisture recovery ventilation and a minimal space conditioning system
- Manages solar gain to use the sun’s energy for heating in the winter season and to minimize overheating during the cooling season
Although Hutchinson’s home is large at 6,800 square feet of heated space, the house was designed for efficient co-habitation with two mother-in-law units for her step-mom, mother (who since died), a roommate and visiting family members. A 15-kilowatt photovoltaic solar system is ground-mounted next to the home and is larger than the home’s basic needs to account for Hutchison’s workshop where she enjoys refinishing furniture. A 2.5-ton geo-exchange system makes the heating and air conditioning extremely efficient aided by the underground year-round stable temperature of the earth.
Home builder Farmer, who wrote about passive houses in past issues of HomeLink, works and consults across Colorado from Eagle to Crested Butte to Telluride. Farmer teams with his wife Lisa, a certified passive house consultant. The couple is working on a six-plex townhouse in Berthoud and two homes in Fort Collins that will be certified passive houses.
“I liked what I saw with Cody,” Hutchinson said. “I was impressed with his interaction with subs, in his trying to mentor contractors and in the quality side.”
The homeowner said the two values that drove her decisions made from overseas were energy efficiency and low maintenance. Since natural gas was not available to her site, making the most efficient use of electricity with a larger solar system was key. She wanted to be as close to net-zero energy use as possible despite the need to power a water pump for well water, her additional workshop and the installation of an indoor swim spa. Hutchinson’s step-mom uses the spa for water walking exercise, and Hutchinson stays in shape as an adult competitive swimmer following her years on the swim team at Western State Colorado University in Gunnison. Even with multiple energy uses at the multi-generational residence, the winter electricity bills average only $106 per month, including standard electrical service charges.
Project architect Kelly Deitman of Halcyon Design in Frederick said the very airtight Travelers Rest, located in a warmer climate zone 5 than Routt County’s climate zone 7, would translate well to the Steamboat Springs area with some changes for snow load capacity with a steeper roof design. Deitman said the home’s extra thick wall assembly (see wall diagram) is a fairly common way for passive houses to achieve a super insulated structure with no thermal bridging, or loss of heat at the point of the wooden studs.
All of the wiring penetrations come in at one location in the mechanical room to cut down on air leakage. The wall where Hutchinson hangs her treasures from years of travels is an internal wall with a cork covering that also serves as a visual break for a movie-watching alcove. Making nail holes in the internal wall keeps the external wall system from having any small penetrations.
Routt County plays a supportive role in the growing passive house movement as home to two certified passive house designers as well as headquarters of Zola European Windows for passive homes. Zola provided all the windows and doors for Traveler’s Rest. Zola owners, husband and wife Florian Speier and Jessica Pfohl, are completing their own passive home, the first in the county to be certified as passive house by both U.S. and European standards. Their Strawberry Park neighborhood home was featured while under construction as part of the fall 2016 Green Building Tour.
Hutchison has lived everywhere from Libya to Sierra Leone, from Kazakhstan to Saudi Arabia, so she loves the peacefulness and calm of her rural Colorado home. She enjoys viewing the local wildlife of deer, pheasant, turkey, hawks, eagles and prairie dogs, even though that cute raptor food can dig holes in her road.
She said her home has no drafts, maintains its temperature well, and has comfortable, even heating and cooling.
“Passive house gives good quality construction and a fabulous end-product,” she said. “We tried to go green as much as we could, and all of that combined together creates low utility costs and a lovely home that is quiet and low maintenance. I think passive house is the way to go. We need to do more of that; we are running out of fossil fuel. Even with slightly increased cost, if we design and built (certified passive) from the get-go, it’s well worth it.”
- Pro Clima brand European made tape and membrane air sealing system
- Heated and cooled by 2.5-ton Bosch geothermal heat pump
- Zola brand aluminum clad windows and doors
- Third-party passive house rating by EnergyLogic in Berthoud
- Final blower door measuring extreme airtightness at 0.34 ACH50
- R-52 insulation value wall assembly above grade (see wall diagram)
- R-45 insulation value subwall below grade
- Four inches of foam for R-20 insulation value under slab
- R-83 attic insulation value
- Backup 20-kilowatt propane generator, used only once in three years
- Air Pohoda energy recovery ventilation (ERV) system at 94 percent energy efficiency
- Bosch 80-gallon efficient heat pump water heater
- 80-gallon side arm hot water storage
- 99 percent LED lighting systems
- Energy Star appliances
- Low-flow water fixtures
- Beetle-kill pine ceiling
- Locally sourced natural stone for lower exterior walls
- 30 percent reflective standing-seam metal roof
- Roof drainage centrally collected and diverted to natural Colorado landscaping
- Estimated 10 percent additional cost to build as certified passive home
Passive House Resources
More information about passive house construction and this northern Colorado project can be found via:
Video tour of Traveler’s Rest: www.LiveUtilityFree.com/TourTR
Passive House Institute US, including Passive Building 101 information, www.phius.org
Certified Passive House in Colorado
Travelers Rest is one of three U.S. certified single-family passive houses in Colorado, said Lisa White, certification manager at the Chicago-based nonprofit Passive House Institute US. As of April 1, the only other two certified houses in Colorado are in Denver and Adams County. Across the U.S., 107 single-family homes are certified so far by the institute.
Basalt, in the Roaring Fork Valley, is home to a certified passive construction office at the Rocky Mountain Institute Innovation Center, which was certified in December 2015.
White said 13 additional projects in Colorado are in the passive house certification process, and retrofit projects also can become certified as passive house. Many other projects aim to be built to passive standards without the official certification.