Fredericksburg SHINES

Leading the Way in Sustainability

Digging Geothermal Heat Pumps

Texas weather can vary dramatically in the span of a couple hours, causing electric and gas bills to skyrocket. Hill Country residents might be able to gain control of those costs by installing a geothermal heat pump (a.k.a. geothermal heater and air conditioner).

According to vice president of Southwest Mechanical, Charlie Lonsberry, about 60 percent of a residential electric bill"”or $60 of a $100 electric bill"”is heating and cooling costs. In his 16 years of experience with geothermal heat pumps, one can reduce that heating and cooling cost by 60 percent"”shrinking that $60 to $24.

A geothermal heat pump is…
Many people in the Hill Country might relate the term geothermal to the energy producing Lower Colorado River Authority. However, a geothermal heat pump neither creates energy nor uses the turbines LCRA uses.

A heat pump is the portion of your air conditioner/heater that adds or removes heat from the air in your home. On a very basic level, traditional heat pumps, run water through coils outside your home. The air running across those coils will either add heat to the water or absorb heat from the water. The modified air will then be pumped into your living space. While this system works, it can take quite a bit of energy"”not to mention wear and tear on equipment"”to remove the heat when the temperature outside reaches 100 degrees.

A geothermal heat pump sends water through pipes placed in the ground where the soil and rock"”rather than the outside air"”will either absorb or add heat to the water. This system takes advantage of the higher conductivity of soil and rock, as well as the relatively constant underground temperature of 68"“70 degrees Fahrenheit"”opposed to the variable air temperature above ground"”to transfer the heat. Once the heat transfer occurs, the water flows back up into the home, where it heats or cools the air.

Geothermal heat pumps move water through pipes in the surrounding ground to transfer heat from the home to the rock, or vise versa.

Courtesy of Howard G. Rogers (original source for diagram unknown)

Cost of a geothermal heat pump
The cost to install a geothermal heat pump can be about twice that of a traditional HVAC system, but Lonsberry insists it is worth it.

He said most of the cost goes into drilling the holes for the piping. When asked how it compares to drilling a water well, he said it is much lower because there is no pump or casing to install and the holes are smaller in diameter.

While the initial cost can deter some people, Lonsberry said it must be viewed as an investment.

"Most of our customers have been pretty savvy in investments, so they see the benefit," Lonsberry said. "They usually see payback in three to six years. The systems then last 25-30 years and just keep paying them back year after year, with little to no maintenance."

Howard Rogers, Fredericksburg resident and geothermal expert, believes installing a geothermal heat pump within the next couple of years will cost a homeowner no more than the cost of a conventional unit when all the tax credits and rebates from the federal government and local power companies are added up. He even calculates the payback for a geothermal system could be seen in as little as two years.

Energy Star has deemed geothermal heat pumps to be so efficient that the federal government is offering a tax credit of 30 percent on the entire cost"”including landscaping and ductwork, if they are required"”till the end of 2016. The tax credit on energy efficient traditional systems, is only 30 percent of the cost, with restrictions and cost limits, until the end of 2010.

Added benefits
In addition to lower energy bills, better efficiency and tax credits, Lonsberry said geothermal heat pumps allow users to keep the temperature higher, and humidity lower, making for a more comfortable environment than traditional units offer.
He points out that one of these systems makes the atmosphere outside on the porch more enjoyable as well, because the need for the noisy outside unit has been eliminated.

A geothermal heat pump can also be modified to heat a home’s usable water with the heat it pulls from the home’s air in the summertime. The result is free hot water and an even lower energy bill. Lonsberry said this little addition to the system makes heating water cheaper and more efficient than even tankless water heaters, so he includes them on every system he installs.

Geothermal in Fredericksburg
Rogers was one of the earliest converts to geothermal heat pumps in Central Texas.

"I spent 20 years running a brick plant…worrying about energy prices"”it was a matter of survival," Rogers said.

The ceramic and brick industry was conscious of energy prices and the benefits of geothermal heat pumps, even in the 1950s, he said.

In 1976 Rogers began a second career in energy consultation, and in 2005, he included a geothermal heat pump when he built his new residence in Fredericksburg.

"I planned every detail of the house carefully"”every light outlet, every appliance, placement of windows, white metal cool roof and insulation," Rogers said. "When it came to the a/c, I had a lot of options, but geothermal takes advantage of subsurface stable temperatures."   Read here to learn more about Roger’s hyperefficient geothermal home.

Lonsberry said many people wonder about drilling into limestone, but his drillers do it everyday. In fact, Lonsberry said, limestone is ideal for geothermal heat pumps because it conducts heat better than soil does. The Llano area, with so much granite, is a bit tougher in which to drill, he admits, but not always impossible.

Installing a geothermal heat pump
Rogers recommends that any person interested in installing a geothermal heat pump inside the city limits talk to the building inspectors and of course the driller himself. Roger said the drillers are very aware of the legal requirements and should help you meet all of them. He recommends using either Advanced Mechanical Systems in Austin or Southwest Mechanical in San Antonio.

Lonsberry said the thing to keep in mind the most when considering one of these systems is space availability. The holes have to be 20 feet apart, and there must be enough room to get the drilling rig"”roughly the size of a dump truck"”onto the lot.

"While open land is ideal, we’ve gone alongside driveways or houses," said Lonsberry. "We can even pave over the holes."

Rogers’ system was installed in his 15-foot setback, but he was particularly impressed by the installation of a system for his friend and City Public Service employee in San Antonio. The gentleman had a home on a tight lot in the King William District and Southwest Mechanical was able to install the system  and still meet the criteria for the historic neighborhood.

contributed by  Aden Holasek    11/01/2010 and updated by John Watson    6/17/2013

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