Note: This house is on the 2013 Solar & Green Building Tour.
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When we began conserving energy through life style changes in 2006 and retrofitting our 1200 square foot conventional 1954 house for energy efficiency, we did not anticipate that our annual utility bill would drop 82%, from $2,278 to $418, but that’s what happened.
For years we listened to friends talk about energy conservation and read numerous environmental books on global climate change, peak oil, population and consumption, and our unsustainable economic and agricultural systems. We decided it was our turn to do something toward making a difference.
The first thing was to make a list and do all of the things we could that would conserve energy, reduce our carbon footprint, and cost nothing to very little. They included: keeping lights off when not needed, using power strips and keeping them off when connected devices are not in use, installing a night setback thermostat, reading by natural light whenever possible, replacing all incandescent bulbs with compact fluorescent ones, removing an unused window air conditioner, using clothes lines outside and in the basement instead of an electric clothes dryer, and cooking food outside in a solar oven when possible.
We then had an energy audit of the house. The results indicated that we had no insulation in the walls and some, but not enough, in the attic. The house was poorly sealed and our boiler and hot water heater were old and very inefficient.
We hired a contractor to blow cellulose into the walls (R-2 to R-12) and increase attic insulation to 18 inches (R-19 to R-57). We installed rigid foam insulation on the basement walls (R-1 to R-12), insulated and sealed rim joists, and re-caulked all windows. As a result, blower door tests showed a decrease in air leakage from 2,390 cubic feet per minute (CFM) at –50 Pascals to 930 CFM, a 60% reduction. The total cost after rebates was $4,800 with a 4 year payback time; thereafter we’ll save $1,200 annually, a dividend on our investment.
We then “bit the bullet” and invested $46,200 in the large ticket items: high energy efficient gas boiler for circulated hot water heat and domestic hot water, an airtight woodstove, and a 3.3 kW photovoltaic system (PV). The cost after rebates and tax credits for small and large actions was $31,000 ($4,800 for small items + $26,200 for big ticket items) with an estimated payback time of 13 years; thereafter an annual dividend of $2,400 ($1850 for energy not purchased and $550 for income taxes not paid).
The combination of new equipment and conservation efforts mentioned above resulted in a 43% drop in energy use and an 86% reduction in fossil fuel use.
By June 2009, the end of the first full year of our plan, we had used 144 Therms of natural gas, 1.8 cord of wood and produced 567 kWh more electricity than we used. We are delighted with the woodstove that keeps our home toasty warm all winter with firewood we scavenge, cut, and split. We are continuing to monitor and fine tune the energy features of our home, but are now looking at other arenas such as transportation and food production in our attempts to be more sustainable.
To our surprise, we have become a positive energy home by producing more energy than we use. And we are also climate positive because the 3,400 kWh of electricity our PV produces keeps
5,400 pounds of carbon from entering the atmosphere thereby more than offsetting the 1,700 pounds of carbon released from 144 therms of natural gas.
We’ve done nothing that special. Anybody can do some or all of these things with their home. Who wouldn’t want to be paid a 25% return on a modest $4,800 investment for a more sustainable future? Even an 8% return on the total $31,000 investment sounds quite good compared with current interest rates.
Howard Stoner is a retired math professor, gardener and lives in a home retrofitted for energy efficiency. He is interested in doing things by hand, the use and care of hand tools: crosscut saws, harvesting scythes, grain threshers, grinders, rollers, etc.