Casa Aguila will arguably be the most advanced home ever built in San Diego County, looking to achieve many firsts for our region. It will be San Diego's first Certified Passive House, seek the County's first onsite wastewater treatment permit, seek the County's first permit to utilize all collected rainwater for all indoor water use, and strive for eventual grid-disconnection through utilization of battery power, Solar PV, and a 45-foot wind turbine (the blades alone are 17 feet tall!).

The project is located in Ramona, CA and is named for the Golden Eagles which frequently fly over the property.

Tuesday, November 4, 2014

The hot water challenge

Gary and site supervisor Jesse Heilig
walking through Casa Aguila
Have you ever looked forward to a relaxing warm shower, only to find you need to run cold water for minutes before hot water finally arrives? Not only is it an inconvenience, but it is a significant waste of a precious resource. We were lucky enough to have Gary Klein, the nation’s leading hot water distribution expert, out at our Casa Aguila site to discuss energy and water conservation strategies. Our goal with Gary was to develop a hot water system for the project that wastes less than one cup of water while waiting for hot water to arrive at the faucet.
Gary Klein,  Former California Energy Commission
Domestic hot water accounts for about 30% of household energy consumption, so there is substantial opportunity to conserve energy and resources by increasing the efficiency of the hot water distribution system. An ideal system would 1) have hot water almost instantaneously, 2) have safe water (not too hot, no harmful bacteria), and 3) never run out. In larger homes such as Casa Aguila, supplying immediate hot water is a challenge because fixtures are often located far from the water heater.

We discussed installing a hot water recirculation pump throughout the house so when the fixture is turned on it has a hot water supply adjacent to it. However, then we needed to address how much water and energy would be spent recirculating and heating the water during long periods of time when no one is using the facilities, such as when the homeowners are normally sleeping. For this concern we explored the ideas of time and motion sensors, or a manual switch, so that ideally the pump would only run right before someone would need it. We look forward to testing the system!

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