Updated: May 9
The existing log home in Old Snowmass was designed to suit its new owners’ needs. The program includes two home offices, an integrated great room for living and entertaining and convenient access to the outdoors. The homeowners wanted the smallest environmental footprint for the remodel, looking at full electrification.
Client Mission Statement: The initial goal for our work together is to analyze whether an all electric house with solar install is the best way to proceed. If yes, I would like you to recommend the type of heating system, and specify an electric furnace and water heater. If electric is not the most effective way to heat the house, what combination of electric and propane should we consider for heating and cooking.
The basis of design was to be efficient as possible, all-electric and if possible, net zero energy. Unlike other parts of the county, natural gas (an affordable option) was not available, so all electric made economic sense and was a healthy choice.
Stop burning things- coal and propane (home heating), and move to the sun
The existing kitchen stove relied on propane and the home heating used R-22. The refrigerant in the existing heating/cooling unit is being phased out, as R-22 refrigerant is responsible for ozone depletion and global warming. In addition to replacing existing systems that are 16+- years old, we removed the dated greenhouse gas (GhG) depleting refrigerant from the existing heating system.
We reached out to Holy Cross Energy (HCE) and Community Office for Resource Efficiency (CORE) before we started our remodel. To go to an 100% electric home, we increased the Holy Cross service panel to the home. We vetted many of our choices, such as Energy Star cold sourced heat pumps and hot water pumps and induction appliances with HCE and CORE and the homeowner. We also conducted an all-home energy audit, sized our heat pumps off of the manual-j calculations (heat loss/heating and cooling needs), and executed blower door tests pre and post construction (building efficiency).
The upgrades to the residence went beyond heating, hot water and home cooking, but included improvements to the building envelope, new chinking to the aged logs and new thermally-broken aluminum fenestration throughout (improved U-Value and SHGC from the existing sieve windows and doors).
The existing roof was cedar shingle, needing to be replaced for both thermal considerations and to lessen fire risk (in a low hazard wildfire area).
We choose a dark metal roof (Class A fire rated roofing). The low albedo roof, reflecting less and absorbing the warmth of the sun and therefore avoiding the need for snowmelt.
The roof envelope was improved through the use of new batt insulation. Before we laid new sheathing and ice and water shield, we filled the cavity with R-21 batt. The new roof assembly and fenestration meets IECC 2018, exceeding currently adopted building codes.
Firewise construction and landscaping
In addition to the removal and replacement of the wood shingles, we updated the fenestration and entrance doors to aluminum clad- improving fire resistance. Further, the existing exterior decks were replaced with fire resistant composite decking materials and treads.
We created a wildfire protection zone, reducing landscaping in “Zone 1”, nearest the home by using crushed stone around the permitter (with the stone/rock, we created a permeable decorative landscaping, without the use of hazardous wood chips) and pruned up low branches and removed vegetation that hung over the roof (and newly installed solar panels).
These architectural and landscape design moves were in accordance with the recommendation of Firewise USA, thereby we minimized the wildfire hazard risks in the “immediate” (zero to five feet) and the intermediate (five to thirty feet). In the extended zone (thirty to one hundred feet), we pruned and removed low branches and cleaned up the water storage pond and pump house.
After we removed the propane tank and ozone depleting refrigerants from the home, our attention turned to resilience. In addition to the 17.68 kWh (originally sized as 21 kWh) solar array on the residence, the home has solar energy battery storage mounted in the garage. The five batteries serve as a microgrid that can be utilized by the homeowner and Holy Cross Energy’s client network. The batteries are part of Holy Cross Energy’s Power Plus program, providing for onsite storage for the photovoltaic system. The graphical depiction of the homes energy use and production and power storage over time are viewed from a mobile phone.
Systems selection and homeowner health
Without a gas stove, we reduced pollutants in the home and thereby improved the indoor air quality for the homeowners. Without a propane furnace, replaced by the electric heat pumps, again we removed pollutants from the built environment. The new cold sourced heat pumps work by the expansion and contraction of fluids, not through fossil fuels and/or the use of greenhouse gas depleting refrigerants.
Triple dipping on financial incentives.
The heat pumps selected are all Energy Star rated. The heat pump for the hot water is Energy Star as well. In the valley homeowners utilized Holy Cross, CORE and Federal Income Tax Credits to offset the investment in a net zero energy home.
What could we have done better
We should have ducted the hot water heater to move the coolth from the source and thereby avoided the need to (potentially) heat near the mechanical equipment (in the winter months). The coolth from the hot water heater should have cooled the wine in the summer and winter and/or cooled the garage in the summer.
We removed the hot tub (reducing exterior energy use), updated interior lighting to all LED with a lighting control system, and updated ceiling fans to provide a reverse mode (pushing warm air down in the double height living room for the heating season).
Project closeout: Blower door test(s)
The result was a 33% improvement in the building envelope as measured by the blower door tests pre and post construction. Any remodel that we perform will include blower door tests pre and post construction and more testing if needed. The testing was instructive to the homeowner, invaluable at detecting what we can or could do better, and an affirmation of the design and good construction practices.
What is left to do?
A hybrid vehicle sits in the garage and when it reaches its end of life, we will install a car charger and complete the whole house and lifestyle electrification.
The image above was from a sunny winter day in January. Imagine the energy offset readings on June 21?