HomeLink Magazine Winter 2015: Conner Residence 

Modern Modeling
Huckleberry Home Prioritizes Energy Efficiency

By Suzie Romig

             Building a new custom home often becomes a series of choices and compromises with cordial but competing opinions among homeowner spouses, architects, builders, interior designers and subcontractors, yet sometimes science simply wins.

Homeowners, and husband and wife Scott Conner and Hazel Hoff, let the contemporary science of energy modeling decide the best design and thermal envelope for their modern, passive solar, energy efficient home completed last year.

“The idea was to integrate the design with the site and modeling to take advantage of every aspect for sun and wind,” Conner said. “What makes the home unique is the integrated design with the owners, engineering modeling, architect and contractor all working together for the end goal of a modern, energy efficient design.”

A professional engineer with twenty-five years of experience in commercial construction including energy modeling, Conner used the free online tool Home Energy Efficient Design, or HEED. Developed at the UCLA Department of Architecture and Urban Design, HEED calculates an hourly heat balance for a home for each hour of the year. Conner used the program to determine his home’s orientation, solar shading areas, insulation targets for the roof and walls, and the number, size and locations of windows.

“The thermal model caused us to get rid of many of the windows or make them smaller. We removed six or eight windows and made 50 percent of them smaller,” Conner explained, because windows let in light but are less efficient than well-insulated walls. Conner said the modeling goal was to create a house with a HERS, or Home Energy Rating System, score of 35, meaning it uses only 35 percent of the energy of a traditional home in the local climate zone 7.

“It pushed us,” project architect Tim Stone said of the extensive modeling. “We would make manipulations to the design, and Scott could make changes to the thermal model on the fly. We could study the effect that the design changes had on the performance almost in real time. It affected primarily the southern and western facades. Seeing how it impacted thermal performance of the house was really helpful.”

The homeowners, who previously lived in a larger home in the Genesee area on the Front Range, started searching for an appropriate building lot in 2008. They prioritized southern solar exposure and good views. They finally honed in on an undeveloped 5-acre lot on Upper Huckleberry Lane in Routt County on the eastern edge of the city. A 12-foot viewing platform helped seal the deal. The couple situated their house’s kitchen at almost the same location and height as the former platform, which means their ground-level two-car garage required a 13-foot ceiling. Wood from the platform was recycled to become a fireplace hearth.

“We said ‘we need this view,’” Hoff remembered, when originally planning the house with builder Michael Roberts. 

Their home was the last project completed by Roberts before his accidental death during a hiking trip in autumn 2014. Conner said he still misses his friend and fellow energy efficient building advocate. The couple had hosted Roberts in fall 2012 when the homebuilder attended a passive house design workshop on the Front Range.

Conner’s plan to use a highly functional, low-slope shed roof was a critical driver in the home’s modern design with its simple, clean lines. It’s a case of form following function, he said.

“We drove around town looking at all of the roof designs and snow melt systems and wanted something that was higher functioning,” Conner said. “Together with the architect we came up with the most functional roof design possible. We decided we wanted something different that performed better than a traditional roof with peaks and valleys and extensive snow melt systems. I believe for this climate a low-slope shed roof is actually the highest functioning roof design that’s available.”

Conner selected a TPO roofing system, or thermoplastic polyolefin single-ply roofing membrane, known more as a commercial roofing material. The light-colored material reflects the summer heat, and the low-slope shed roof was engineered for a stronger load to hold snow for an added layer of natural insulation.

With the shed roof, the home has no attic space and tall interior ceilings: sixteen feet at the peak in the living/dining area and fourteen feet in the master bedroom. So the couple hired their neighbor and interior designer Bruce Caplowe of Rumor Design + ReDesign to help warm and soften the tall rooms. Caplowe chose to paint the ceilings and tops of the walls in warm gray, to use a horizontal band of white trim to define the room height at ten feet and to paint the walls in “fawn brindle.” Some examples of the modern interior design touches include a burnt orange circular light fixture three feet in diameter in the master bedroom and a bright red geometric design light fixture above the dining table.

The most intelligent ingredient in the modern home is a Vera brand smart home controller program that can be viewed as an online dashboard via computer or smart phone. With Conner’s engineering background, he is a pro at this simple, wireless platform that monitors and controls electric usage, thermostats, motion sensors, the house music system, relative humidity, energy recovery ventilation (ERV) and domestic hot water circulation. When the home automation program turns down the house at bedtime—if the refrigerator or heat system is not cycling on—the entire two-story home can use as little as 100 watts of electricity. That’s similar to one old-fashioned bright incandescent bulb.

After tracking their energy use for the first year, the couple’s electric bills average $50 per month including both base charges and power consumed, and monthly propane bills average $41, Conner said. The first year, the couple’s home used an average 324 kilowatt-hours per month, a low consumption level that even frugal homeowners in the area can only envy. The couple installed an on-site 2.8kW photovoltaic solar electric system in November 2015, which will make their electric use net zero starting the home’s second year.

Matt Piva with Brightside Solar in Steamboat Springs said the grid-tied, ground-mounted system will offset 108 percent of the home’s electrical usage. With modern inverter technology, the system will be able to generate electricity for the home during daylight hours even when the electric utility service might be down.

Through the smart home system, Conner stays extremely well informed about what uses the most electricity each day. He has plugged in wireless switches made by Aeon Labs on six key electric outlets to reduce phantom loads and unnecessary power usage. The control switches are at work on the whole house stereo amplifier, ERV, hot water heat circulation pump, Hazel’s home office, timed security lamps, and the outlet to recharge camper batteries. The couple also utilizes a motion sensor installed above the master bathroom door to alert the hot water circulator to run for two minutes.

The outside of the home is designed for very low maintenance. The sturdy exterior features 80 percent steel siding, 15 percent stucco and 5 percent beetle kill pine. The driveway and front entry face south to take advantage of the sun for natural snow melt. Native, no-water landscaping allows the couple to live off a well water permit for domestic-use only.

The contemporary flooring throughout the house is black porcelain tile with concrete board underlayment to capture and hold heat, thus allowing a smaller first-floor hydronic heat system with classy Runtal brand radiator units. The ground-level of the home utilizes in-floor hot water heat, all designed and installed by Aaron Scarborough of Downhill Plumbing & Heating and powered by a New York Thermal 96% efficient boiler with touchscreen controls and internet capabilities.

Stone, with Kelly and Stone Architects in Steamboat Springs, said this home had the advantage of the most extensive 3-D computerized energy modeling that he has experienced with any residential project in his busy 15-year architecture career. The modeling confirmed the home’s exact footprint because “just a few degrees can dramatically impact the passive solar performance,” Stone explained.

Local architects estimate that only 5 percent of homes built in this area take advantage of computerized energy modeling. The modeling also determined the placement and angle of architectural louvers, or engineered aluminum sunshades used above the exterior of the south-facing windows.

Conner, Stone and other locals say the construction trades industry in Routt County has needed some nudging and training to be able to build and bid accurately for high energy efficient levels such as LEED and Passive House.

“It was harder four years ago when we started the design process,” Conner remembers. “People had not pushed the architects or subcontractors hard.”

Another sustainability consideration for the 2,100-square-foot Huckleberry home was appropriate sizing for a house built for two adults and one dog.

“It was a conscious decision to not make spaces bigger than they needed to be,” Hoff explained.

The couple prioritized performance over size and “amazing finishes,” they said. Unnecessary elements such as faux living room ceiling beams, nonstructural outside beams and large additional decks were cut.

 “We started stripping off everything superfluous,” Conner said. “Everything that didn’t have a function went.” His modern design mantra remains, “Perfection is not achieved when you can’t add anything else; it’s achieved when you can’t remove anything.”

Energy Efficient and Sustainable Features:

  • Passive solar design with home oriented to south
  • Photovoltaic solar electric system
  • Smart home computer program and wireless switches for energy efficiency
  • All Energy Star rated appliances
  • 95 percent efficient New York Thermal, propane-fired, hot water boiler with separate heating zones for two floors to conserve energy on the less-used ground level
  • Natural landscaping
  • Architectural louvers and roof overhangs to let in low-angle winter sun and provide shading in summer
  • High efficiency hot water circulator pump
  • Programmable, wirelessly connected thermostats
  • Alpen brand high performance windows with different solar heat gain coefficients for different sides of home
  • High insulation values for building envelope: attic R63, walls R30, slab edges R10, under slab R24
  • 99 percent LED and CFL bulbs
  • Extensive daylighting in all rooms include upstairs bathrooms
  • EPA Water Sense certified toilets with 1.2 gallons per flush
  • Dark Sky certified exterior light fixtures

Other Local Key Subcontractors:

-          Light Works of Steamboat – sourcing modern LED and CFL fixtures

-          Downhill Plumbing & Heating – efficient hot-water heat system

-          Fin’s Tin – energy recovery ventilation