Concentration of CO2 in the Atmosphere

Zero Energy Now

Farmhouse, Underhill, VT. Energy saved: 88%; annual energy cost savings: $3,885. 71% renewable energy – solar PV, cord wood, and pellets. Photo: Building Energy

George Harvey

The June 2017 edition of Green Energy Times had an article, “Saving 79% in Existing Homes,” which provided an initial report on the results of the Zero Energy Now (ZEN) program ( The program was designed by Vermont’s trade association of home performance contractors, Building Performance Professionals Association (BPPA), in 2015. Its purpose was to save fossil-fuel use in existing homes in Vermont.

Farmhouse, Newfane, VT. Energy saved: 98%; annual energy cost savings: $2,901. 94% renewable – solar PV. Photo: Integrated Solar Applications

The ZEN program was supported with funding from Green Mountain Power, through its Community Energy & Efficiency Development Program. The funding came through in February 2016, and the work on homes had to start quickly after that, in order to be completed on all of the projects before December 31 of that year.

Each site had to be evaluated. Weather sealing had to be done and insulation installed. Heat pumps were installed for heating and hot water, and those for heating were either air-sourced or ground-sourced, depending on the individual situation. Solar systems were also installed as major parts of the projects.

An overall study to examine the results of the program included 24 of the buildings in the program, about two-thirds of the total. The study showed that the program led to impressive savings. The program and other incentives had reduced homeowners’ costs of installation to a net average of $31,090. The average savings on energy came to $3,692 per year, which is a return on the investment of 11.9%,

Together, these homes had reductions of 8,820 gallons of heating oil and 3,103 gallons of propane. The solar systems generated 201,468 kilowatt-hours of electricity. The great majority of the homes had energy savings of over 40%, the average was 79%, and one saved 98%.

Raised ranch, Thetford, VT. Energy saved: 95%; annual energy cost savings: $2,042. 94% renewable – solar PV and cord wood. Photo: Building Energy.

There were a number of lessons learned from analysis of the projects in the pilot program. One is that a comprehensive approach to energy savings is very important. The systems put into place should be able to work together toward the goal of reducing energy and fossil fuel use. The overall design for a project must take this into account.

There were two observations about heat pumps. One is that it is important that the unit be properly sized for the house. Another is that wood-fired heat is a good backup.

None of the homes in the program was new, and the designs of the homes varied widely. Because of this, the program was able to demonstrate that the methods used are broadly useful. Even rather old buildings were able to benefit from the upgrades.

One particularly noteworthy finding is that occupants of the homes should be educated about how their new energy systems operate. This is especially true in relation to heat pumps, which are not familiar to most people.

Having done that work and evaluated the results over time, BPPA is bringing ZEN back. This time, the program is no longer a pilot project. Instead, it is starting up with intention of making use of the lessons of the pilot as an ongoing effort. The new full ZEN program will be kicked off in June or July, once the final formulating stage is complete. The program will begin with contractor training and jobs for those who took part in the pilot.

Ranch house, Jericho, VT. Energy saved: 95%; annual energy cost savings: $1,732. 90% renewable – solar PV. Photo: Building Energy.

BPPA hopes to complete retrofits on ten homes by the end of this year. The intent is to double that number in 2021, and double that again in 2022.

One thing that is getting a lot of attention by the people involved at BPPA is financing. There are several foundations involved already, including funding from the Energy Foundation, and commitments from Vermont Community Foundation and Efficiency Vermont. BPPA is working with Northeast Energy Efficiency Partnership. And it has a number of grant requests already underway.

Clearly, homeowner participants are needed, though only ten can be chosen this year. Anyone interested should contact Gabrielle Stebbins at 802-825-9515.

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