Evacuated Tube Solar Hot Water System
Our customers Ron and Sandra have a large family, but limited roof space, which made it a challenge to fit a solar hot water system on their roof that would meet their needs. Evacuated tube solar hot water collectors, though more expensive than flat plates, are able to provide more heat per square foot of collector and thus were a good match. Evacuated tubes’ superior collection power is made possible by a vacuum that surrounds the collector in each tube. Similar to a Thermos, the vacuum ensures there is virtually no heat loss once the sun hits it.

Drain Back Design
The solar fluid for all solar hot water systems need to be protected from summer-time over-heating and winter-time freezing. To this end, we chose to implement a drain back design for Ron and Sandra. This means that when the system is off all of the solar fluid automatically falls back into a holding (drain back) tank in the basement, and the air that was in the drain back tank rises up into the collectors. The collectors themselves are designed to withstand the heat that they create.

Smart Hot Water Recirculation
Ron and Sandra enjoyed having hot water come quickly to their faucets because there was a recirculation loop that circulated hot water constantly through the pipes and back to the tank in the basement. Running a recirculation loop all the time, however, uses a lot of fuel and electricity. So we upgraded the system to one which uses a switching mechanism that is simply controlled by momentarily turning any hot water faucet on. The recirculation loop is then activated for a short period of time—enough to flush the cold water out of the lines.

Prior to starting our business we built a super-energy efficient, net zero energy home for Spartan and his family in Greenfield Massachusetts. That home recently won a regional building contest for net zero homes! It is a huge honor to have won and be recognized. In addition to a substantial prize, we had the opportunity to present in Boston at  the Northeast Sustainable Energy Association's (NESEA) annual Building Energy conference. NESEA will also be hosting a Pro-Tour at our home on May 1st. 
One of our missions has been to help people learn about how to make their buildings more energy efficient and having our home be recognized will help us towards this goal. Also toward this end, we have a blog where we documented the entire-design build process from including temperature, humidity, and energy data logged since spring 2012.
During the inaugural year of our small 4.5 kW PV system (Oct 2013 - Oct 2014) our home generated as surplus of 500 kW. This performance did not come at the cost of comfort: the average indoor winter-time temperature during this time period was 68 degrees F. In addition to creating a high-performance home, we strove to decrease the carbon footprint of created by construction. We reduced high carbon footprint materials like concrete, foam, and drywall. We also used a significant amount of salvaged materials including siding, windows, doors, sinks, cabinets, stone flooring, and foam insulation board.
The Net Zero Energy Building (ZNEB) contest is put on every year by the Northeast Sustainable Energy Association (NESEA). There were six other finalists including entries by the well-known building scientist Marc Rosenbaum and fine-home builder  Jamie Wolf.
We thank all of our friends and family for making this project possible. Especially Adam Heintz, our lead carpenter who is also our partner here at Spartan Solar.