Geothermal-fueled Home Green from Ground Up
Electronics not only save electricity, they help regulate a geothermal system in this Chesapeake Bay gem.
November 03, 2009 by Steven Castle

There are lots of ways to be green—or greener—and this 4,500-square-foot designer’s delight on the Chesapeake Bay sports several of them. There’s a geothermal heating and cooling system that pulls clean, carbon-free heat from the ground. There’s a lighting control system that helps to save energy, motorized shading to keep rooms cool during the day, and easy and convenient control of everything.

The green initiatives began with 14 bore holes drilled 120 feet into the ground for the geothermal heating and cooling system, which pulls heat stored in the earth to warm the house. The earth’s subterranean warmth heats a glycol-based liquid in a tube, which circulates to a heat exchanger, and then warms a refrigerant that goes to a compressor. The resulting heat is blown into the rooms via a forced air system.

The geothermal system also cools the house during hot months. This works by drawing heat out through the glycol tubes and into the earth, cooling a refrigerant in a compressor, and blowing cool air.

This system goes above and beyond, using five different heat exchangers and employing dampers in many areas that close off unused rooms to the heating and cooling system, thereby saving energy.

This is where a whole-house control system comes in handy. In this case, a Crestron home control system uses thermostats in some areas and inconspicuous, 1.5-inch diameter heat and humidity sensors in others to monitor even the most minute (less than 1 degree) changes in temperature. The Crestron system monitors the climate of the house so the heating and cooling systems operate at maximum efficiency, says Lynn Hopffgarten of electronics systems installer Boulevard Audio, located in Alexandria, Va.

To save electricity, a Crestron lighting control system was used for the 50 zones (or circuits) of interior and exterior lighting. The previous house’s exterior lighting system was redesigned, with lighting added for a new pier, pool gazebo and in-ground pool. However, the exterior lights’ energy consumption was reduced from 3,000 watts per hour to less than 600 watts per hour, thanks largely to the use of more efficient lighting fixtures, says Hopffgarten. The exterior lights are also on timers, and only a few basic lights are illuminated when the owner is away.

Motorized shading also helps to save energy. Drapes and shades on two Somfy Systems motors in the master bedroom close during the day to help keep the room cool.

A Crestron touchpanel provides central monitoring for the Jandy pool equipment and alerts for floods, which can occur on the Chesapeake shore. The home’s underground sump pump system has a monitoring device that alerts the homeowner when the pumps are needed and when they need servicing.

The touchpanel is also tied to the National Weather Service to receive real-time updates, so the homeowner can adjust the home’s energy systems as needed. When she’s away, she can access the same controls through her computer and Crestron’s XPanel, which replicates the commands of the master controller. “It looks identical to the 15-inch touchpanel and operates with the point-and-click protocol of the computer, just like the touchpanel,” says Hopffgarten. 

Via in-wall touchpanels like the one above, a house-wide Crestron control system operates audio/video systems, lighting, and outdoor lighting, audio and pool control (middle photo). The Crestron system also regulates the heating and cooling provided by the renovated Chesapeake Bay home’s underground geothermal system.

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Steven Castle - Contributing Writer
Steven Castle is Electronic House's managing editor. he has been writing about consumer electronics, homes and energy efficiency topics for two decades. He is also the co-founder of GreenTech Advocates.


Boulevard Audio
Alexandria, Va.

Residential Systems Design
Exton, Pa.

Townsend Industries
Germantown, Md.

Accent General Contracting
Rockville, Md.

Thomas Pheasant
Washington, D.C.

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