One of my favorite tales as a child was Jules Verne’s “Journey to the Center of the Earth,” a classic adventure story about a German professor and his volcanic trip from one end of the planet to the other.

Even then, I could not have imagined widespread use of the power beneath our feet to operate home heating systems. But, as Kenny Chesney would say, “welcome to the future.” Now, geothermal (“ground source”) heat pumps are readily available to Mobile area homeowners.

According to California’s Consumer Energy Center, ground source heat pumps work much like traditional models, which extract heat from outdoor air and transfer it throughout the interior of a building.

Apparently, even cold air has heat lurking within it, but basic heat pumps sometimes struggle to take heat from blistering cold air in the dark of winter.

In comes the ground source pump to combat that problem. A geothermal unit draws on the relatively consistent heat of the earth (45 to 75 degrees Fahrenheit, 65 to 70 degrees in Alabama) to provide interior heating and, in most cases, hot water and air conditioning. It doesn’t take long to see the efficiency advantage of a system that relies on a stable energy source over one that is dependent on wildly fluctuating surface air.

The process does require a small amount of electricity, which may be why Alabama Power has an entire Web page devoted to geothermal pumps.

While all this is interesting, the bottom line is important to most consumers. Installation costs can be significant, but the EPA estimates that ground source heat pumps reduce home energy costs by at least 30 to 40 percent, with little to no recurring maintenance. ClimateMaster, a publicly traded company in the geothermal business, is quick to promote its “savings calculator,” ostensibly allowing potential buyers to assess the feasibility of buying a ground source pump. ClimateMaster’s Web site also points to a federal tax credit amounting to 30 percent off such a purchase.

The Energy Improvement and Extension Act of 2008 allows for a one-time, dollar-for-dollar tax credit of 30 percent of the startup costs associated with a geothermal unit. A 10 percent credit applies to commercial systems. With all the information about tax incentives and savings, it is tough to find basic prices on any seller’s Web site.

However, CostHelper.com reports that people are paying between $3,500 and $7,500 for geothermal heat pumps, but shelling out $10,000 to $25,000 for drilling and installation. So, like the buyer of a hybrid car, a ground source pump purchaser may take some years to realize energy savings, even with the government’s discount program. To help speed the process along, the Recovery Act provides for $338 million in grant funding for geothermal research, which may reduce costs in the long-term.

I talked with Clay Doyle, who is president of Geothermal Solutions in Mobile. Doyle installs Water Furnace brand ground source systems that provide heating, cooling and hot water. He has installed 30 such units since June of last year. He noted that there has been “more interest in Baldwin County,” but that Mobile business is “starting to take off,” particularly in historic areas such as Oakleigh.

Doyle said historic homes using traditional systems can sometimes run up $700 utility bills, depending on the size of the house. Other factors can play a role as well, including insulation and windows.

According to Doyle, geothermal devices cost about $2,000 per ton more than traditional heat pumps. However, his experience has been that the 30 percent tax credit typically makes up for the increased cost. The primary culprit for the higher price is the ground loop that actually goes into the Earth, usually about 240 feet deep.

But, there are definite monthly cost savings. Doyle estimates heating and cooling costs drop by 50 to 70 percent with a Water Furnace system. There are several reasons for the decrease. First, the heat is drawn from a stable source, Mobile’s 70-degree ground temperature. Second, the Water Furnace units use water-filled pipes to transmit heat, and water is a more efficient conductor than air.

Thanks to a lot of innovation and a little incentive from Uncle Sam, you too can take a journey to the center of the earth, right from your warm and cozy living room… Well, maybe after a cold trip to the bank.