The Scott’s reduced their energy usage by approximately 35% (electricity by 38% and natural gas by 34%) saving approximately $890 per year. These savings are largely due to the radiant floor heating system, solar hot water heater and envelope enhancements.
Reduced water usage by 35% saving approximately $330 per year in water and sewer charges. Even with a new baby at home, and associated daily laundry, their water usage remains within the Water Bureau's lowest tier. Alan notes, "Combined (energy and water savings), that's worth more than one free mortgage payment per year."
Annual CO2 emissions were reduced by approximately 2,800 pounds (equivalent to planting 108 trees). Purchasing green power further reduces emissions by approximately 3,642 pounds of CO2 per year (equivalent to planting 140 trees). Due to this, the Scott household "sinks" approximately 840 pounds of CO2 per year. These numbers do not include the savings realized by the recently installed (January 2004) 3kW PV system.
Alan and Ana took advantage of State of Oregon Energy tax credits for the solar water heater, clothes washer, and water heater as well as a utility rebate for the water heater. The City of Portland’s G/Rated Program gave the Scott’s a $3,000 grant to reward their long list of green building strategies.
The installed cost of the 3kW grid-tied PV system was $18,000. The Energy Trust of Oregon paid for "more than half" of the cost and the Scott's also received an additional $1,500 State of Oregon Energy tax credit. Concerning payback, Alan notes, "With today's low electric rates, it may take awhile for the savings to cover my investment, but the system has already increased the value of my home giving me a positive return on investment, and not having to pay an electric bill for several months a year feels great."
Building permits were needed for the addition. A plumbing permit was obtained for the solar hot water heater and a mechanical permit for the radiant floor heating system. While there was not difficulty obtaining the permits, the inspectors were unfamiliar with some of the technology, such as the heat recovery ventilator and the radiant floor heating.