Heating from the ground up

Energy savings is a hot topic, but implementing the technology to do so often translates to big spending upfront. However, over the long haul, the savings can be phenomenal. Such is the case with the geoexchange system, which utilizes heat stored in the earth.ìThe earth is like a battery that stores half of the solar energy that strikes its surface,î said Ed Williams, owner of Black Forest Heating & Cooling, an accredited geoexchange installer in El Paso County.ìIn the Colorado Springs area, the temperature below the frost line is a constant 50 to 55 degrees, even during winter,î Williams said. ìWe install (geoexchange) systems that circulate a mixture of water and anti-freeze through pipes in the ground. The system concentrates the heat in the circulated liquid into heat for the home, he added.Williams said there are several types of geoexchange systems, but the closed loop horizontal and vertical systems work best in Colorado.The closed loop horizontal system consists of pipes that are laid below the frost line ñ 7 feet below the surface ñ over an area about 40 feet wide and 110 feet long, depending on the size and insulation characteristics of the house or building. The pipes are interconnected at the bottom of a series of wells ñ depth between 200 and 400 feet ñ so the fluid flows in a circular motion to the structure to be heated.ìThe two systems are equally efficient,î Williams said. ìIf dirt can be dug out easily, and we donít need to bring in fill dirt, the closed loop horizontal system is usually the least expensive to install. We did a closed loop horizontal installation in the mountains where the ground was so rocky we had to bring in gravel to support the pipes, which used up some of the cost savings.îBlack Forest Heating & Cooling, which also installs conventional heating systems, has retrofitted 16 houses with geoexchange systems since 2004. In all cases, an existing gas or electric furnace was replaced with an electrically driven compressor and heat exchanger that concentrates the heat in the closed loop system and releases the heat inside the home.ìWe can use existing ductwork,î Williams said, although he said he prefers to circulate the heated water through pipes under the floor because doing so eliminates exchanging warm water to air.Geoexchange systems also work in reverse, cooling the house in the summer by extracting heat from the air in the house and transferring it through the heat pump to the ground loop piping. Geoexchange systems also heat water, which can be stored in existing water heaters. ìAlmost all of our customers choose the water heating option,î Williams said.Although itís been around for more than 50 years, when Williams installed their first system the building inspectors were a little perplexed, but theyíre more familiar with it now, he said.Most people donít know about the systems, Williams said. ìWhen people hear about geoexchange and compare the installation cost, which is about $25,000, with a standard furnace system, they usually opt for what theyíve always known ñ the standard furnace,î he said. ìBut when you consider the cost savings over the life of the system ñ (and) loop fields have a 50-year guarantee ñ geoexchange systems result in huge savings.îThe Geothermal Heat Pump Consortium provides the following analysis for a 3,067-square-foot home in St. George, Utah, based on electricity at $.046 per kWh, natural gas at $0.55 per therm and propane at $1.40 per gallon:

HVAC system	Annual Heating	Annual Cooling	Annual Hot Water	Total Annual Cost
Propane furnace and electric A/C	$839	$592	$337	$1,768
Gas furnace and electric A/C	$314	$592	$122	$1,028
Air source heat pump and electric AC	$218	$592	$183	$993
Geoexchange	$64	$166	$98	$328

Williams conservatively estimates a payback time of nine to 10 years. With propane recently at $1.64 per gallon, an investment in geoexchange should pay for itself even faster.ìI know of one geoexchange system thatís been in operation for 55 years,î he said. ìUnlike air conditioners, which lose efficiency and lifespan when exposed to weather, all the parts of a geoexchange system are protected in the ground or in the house. Gas furnaces have a comparatively short lifespan because of parts that break after years of constant expansion and contraction. These parts cannot be repaired, and you have to replace the entire furnace. But all the parts of a geoexchange system are repairable.îWilliams said there are approximately 900,000 geoexchange systems in operation today in the United States. Many of the systems heat and cool public buildings.In 2000, Colorado Springs School District 11 installed a $400,000 geoexchange system in their 26,000-square-foot facilities center. The system consists of 32 heat pumps and 32 ground heat transfer wells drilled to a depth of 300 feet. Energy manager Thomas Fernand said the system has worked so well, it would be irresponsible not to use it in new schools. He expects the system to pay for itself this year and then save the district $250,000 in reduced energy costs over the next 20 years.In 2004, Lewis-Palmer School District 38 installed a geoexchange system consisting of 34 heat pumps and 42 ground heat transfer wells that provide 80 tons of cooling and 1,000 MBTUs of heating for a 34,000-square-foot administration building. Plans for the districtís new high school, Palmer Ridge, include a geoexchange system.ìIt will be a 200,000-square-foot facility for 1,200 students,î said Jeffrey Chamberlain of RLH Engineering, a consultant to the project. ìThe system will have 285 ground transfer wells about 400 feet deep. It will be a hybrid system with a boiler to meet peak demand.îìThere are more upfront costs with geoexchange,î said Henry Reitwiesner, director of planning and construction for the Falcon School District. ìWe decided not to pursue it for the new high schools, but we have incorporated geoexchange in our technical guide for new construction.îThe new D 49 high schools will be using another energy savings technology. ìWe have a requirement for A/C, so weíre installing equipment that makes ice at night, when electricity rates are low,î Reitwiesner said. ìThe ice will cool water, which will circulate throughout the buildings during the day for cooling.îMitigating some of the upfront costs of the geoexchange system are a few tax benefits.Owners of qualified geoexchange systems are eligible for a $300 tax credit under the Energy Policy Act of 2005, as long as the system includes integrated hot water heating.Through the ìEnergy Efficiency Credit Program,î Mountain View Electric Association and Tri-State Generation and Transmission Association offer a credit of $250 per ton and $100 for each direct exchange ground source attached electric water heater, according to the MVEA Web site. ìThat adds up to $1,100 for a typical geoexchange installation,î said Jane Williams of Black Forest Heating & Cooling.The Environmental Protection Agency, according to its Web site, cites greatly reduced energy costs, reduced greenhouse emissions, the quietness of the operation and low maintenance costs as benefits of the geoexchange systems. The EPA references the system as ìamong the most efficient and comfortable heating and cooling technologies available for homes and other buildings.îApparently, the geosystems are catching on. Williams said installations are growing 10 to 15 percent a year.For more information on geoexchange systems, visit www.geoexchange.org or www.epa.gov.