LITCHFIELD — Do-it-yourself geothermal heat and air-conditioning is worth a try, says a Litchfield civil engineer.

A Web site by Peter Tavino, PE, shows pictures and explains how he and his wife Mary installed their geothermal system. Complete with site plans and charts of ground temperatures, Tavino challenges others to give it a try.

You don’t need to be a licensed engineer to do this, Tavino said.

  “I want people to learn how to do this and do it themselves,” Tavino said. “I want to share the information. The days of keeping information for personal wealth are over.” 

The system uses 730 feet of 2-inch diameter geothermal pipe, the site says. They laid the pipe in a trench averaging 5 to 6 feet, but went as deep as 7 feet. Much of the pipe is laid in groundwater, which is a good conductor for geothermal heat.

The buried pipe connects to the new heat pump in the basement and makes a series of loops before returning to the basement as a closed loop system, the site says. A combination of water and biodegradable food-based antifreeze runs through the system.

Average ground temperature in Litchfield is 50 degrees. By the time the fluid returns through the pipe, it is either warmed or cooled by the earth.

“We run the 50 degree water through a heat pump that Connecticut Licensed Heating Contractor Carl LePere describes simply as sort of a reverse refrigerator,” the site says. “By compressing Freon, we draw heat from the 50-degree water, and return it to the underground pipe at about 40 degrees. For cooling, we reverse the hybrid heat pump, and return it to the underground pipe at 60 degrees. By the time the pipeline water completes its 730 foot long underground loop and returns for more heat pump use, it is back to its 50 degrees or so.” (Indoor room temperature is as set at 70 degrees or so.)

The system will service the 2000-square foot first floor, the site says. The Tavinos expect to cut their heating oil usage in half, by 500 to 600 gallons per year, and cut electric air conditioning cost in half.

The site lists the estimated cost of materials for the construction. Tavino estimates that the project would cost $10,000 for the do-it-yourselfer with HVAC experience; $15,000 if a lot of help is needed and $20,000 for those who want the full installation done for them.