The 28th home has officially met the Thousand Home Challenge! The POS Dream House, nestled in the Sierra Nevada foothills, is the first house in Nevada County and the eleventh home in California to meet the Challenge.
Gavin Healy and Elizabeth Dieter bought their 1880’s Victorian home in 2006.Since then they embarked on major remodeling/retrofit effort that included making structural repairs, insulating the home’s foundation, walls, and roof and totally revamping the mechanical, plumbing and electrical systems. The project has served as a living laboratory for Balance Point Home Performance with the performance of the home’s systems extensively submetered.
In November 2015, Balance Point Home Performance removed the natural gas AO Smith Vertex water heater and replaced it with a Sanden split system CO2 heat pump water heater (GAU-A45HPA) and matching 80 gallon stainless steel tank (HP31555D). This Sanden CO2 installation will be monitored by the Bonneville Power Administration and Washington State University this coming year. Info on past product evaluation results are posted here. The Sanden CO2 HPWH will be introduced to the US market as soon as it gains UL approval.
Using OPTION B, with the gas combi heating system, the home’s 1000 Home Challenge threshold was originally 7,570 kWh/year. They narrowly missed the target with the annual site energy use of 7,812 kWh. In the year since the Sanden CO2 HPWH provided space and water heating the annual site energy use dropped to 3,923 kWh! With 100% electric heat the OPTION B threshold is now 5,264 kWh/year, and Gavin and Elizabeth easily met the Challenge. Even with a warmer heating season last year, a reduction of over 50% of their total household site energy use from one intervention is very impressive. Stay tuned for the case study that details the fine-tuning that Gavin performed to optimize the combi system’s performance.
Attched is a graph showing the home’s pre (Dec. 2013 - Nov. 2014) and post (Dec. 2014 - Nov. 2015) energy performance compared to the 1000 Home Challenge thresholds.