It is hard to miss the yard signs appearing on more and more Evanston lawns — “We’re Going Solar” and, by way of explanation, “Solar Hot Water System Installed by US Solar Network.”

Observers can expect to see solar panels appear on roofs and, once a complete solar hot water system is in place, can track a disappearance of sorts: Each system reduces greenhouse gas emissions by an amount almost equal to taking one car off the street per year, says Bill McDowell of US Solar.

 Ingenuity, not magic, is responsible for those vanishing vehicles. Three local environmentalists/entrepreneurs intent on reducing Evanston’s carbon footprint seized an opportunity and launched US Solar Network in January 2013. Two of them, Mr. McDowell and Susan Lang, had previously worked together in his design business. Mr. McDowell and the third founder, construction developer Ron Fleckman, have served in various capacities at the non-profit Citizens’ Greener Evanston.

Mr. McDowell says he and Mr. Fleckman had met “plenty of like-minded people” in the community and had been thinking, “If we could find the right approach to alternative energy in Evanston, this would be the place.”

 They investigated other energy alternatives before settling on solar-heated water. They found electricity-producing photovoltaic cells too expansive and expensive for most residential uses. But they adopted the concept of group purchasing that became the centerpiece of their business from a photovoltaic model used in the East and Pacific Northwest.

 They discovered that substantial savings – government rebates and tax credits as well as reduced utility bills — can be realized when participants form an interest group. As environmentalists, the business owners saw great potential in the fact that the price to install a group of solar hot water systems is just a fraction of what individual systems cost in the past. Once prohibitively expensive, solar hot water systems might now be affordable enough to attract a critical number of residents. The effect of this alternative energy source on Evanston’s greenhouse gas emissions, formerly negligible, could be significant.

It remained for US Solar Network to find a solar hot water system that fulfilled three requirements, Mr. McDowell says. The product had to be made in the U.S., be of very high quality and be produced by a firm with a long history in the field.

A California company called Heliodyne met US Solar’s high standards.  Heliodyne has specialized in the manufacture of solar collectors and heat-transfer appliances since 1976 and has developed a system especially for cold-weather climates.

Customers sign up through the Solar H2O Community Program, SHOP. Each is required to pay a $500 enrollment fee, which US Solar cashes only after the group reaches the 20-household minimum needed to qualify for discounts based on bulk purchases.

US Solar is relying on its proliferating yard signs, along with its website and social media, to “create a buzz,” Mr. McDowell says, adding, “like Tupperware.” The company provides a free consultation to discuss the program and decide whether a home, business or condo is suitable. Even before the home visit, a staff member assesses the home from the aerial view on Google Earth. A south-facing roof is ideal for the two 4-8-foot panels, but different mounting options do exist for roofs oriented in another direction, Mr. McDowell says.

The system has three parts. On the roof are the solar panels or collectors, in which a half-glycol (antifreeze), half-water mixture flows through tubes, absorbs heat from the sun and then moves on. “Even when the outdoor temperature was -13,” Mr. McDowell says, “the glycol was at
120 degrees.”

In the basement a second hot water tank is installed next to the existing hot
water heater and the two tanks connected. The existing tank remains as a back-up, since the solar system provides an estimated 80% of a home’s hot water needs. Flexible tubing, usually mounted on the outside of Evanston’s historic houses, carries the heated fluid from the roof collectors to a closed-loop heat-transfer appliance that looks like a large padlock and is located on the side of the storage tank.

Once the fluid has released its heat to the water in the tank, the glycol mix is pumped back up to the roof to be reheated and, like blood from a heart, to circulate again, except on sunless days, when a back-up system is automatically activated.

SHOP customers pay $14,750 at installation. US Solar takes it from there, handling the paperwork that will result in a $4,425 federal tax credit, a $4,425 Illinois rebate and a $2,950 SHOP 2 rebate. It may take a year to get the rebates, but in the end the net cost to the customer is $2,950. With projected annual utility-bill savings of $432, US Solar estimates payback in a little less than seven years.

According to Heliodyne, heating water by conventional means (with 100 million heaters, 50% of them electric and 50% gas) produces 30% of the emissions from a typical American home. Now on all but the cloudiest of days, the sun heats the water in the 65 Evanston households already enrolled in SHOP. This will eliminate more than 70 metric tons of CO2 emissions annually, equivalent to the emissions of 75 cars, Mr. McDowell says.

The City reached the goal of its 2008 Climate Action Plan in 2013, reducing GHG emissions by 13% relative to a 2005 baseline. City government achieved the greatest reductions, with citizen efforts lagging behind. US Solar Network hopes to persuade Evanston residents to convert to a solar hot water system, aiming for 100 participating households by the anniversary of its first installation. That should result in a leap toward the Citizens’ Greener Evanston new emission-reduction goal of 20% by 2016.

The heart of SHOP, Mr. McDowell says, is “working with your neighbor.” The program’s contribution to the environment of their hometown is a point of pride for US Solar Network. “We are an Evanston business working in Evanston,” he says. “We take that seriously.”