Energy Saving Ideas

Geothermal Heat Pumps Worth the Investment

As energy costs increase, lowans are looking for ways to improve home energy efficiency and lower utility bills. For people building a house or replacing a heating system, a geothermal heat pump system (GHP) is worth consideration. A geothermal heat pump system can provide a home’s heating, cooling, and hot water with indoor comfort and lower energy bills.

What is a Geothermal Heat Pump?
A heat pump warms a home by transferring heat rather than creating it. A GHP loop system moves heat from the ground into the home during the winter while pulling heat from the home and dispersing it into the ground in the summer. The earth is consistently warmer than the air in the winter and cooler than the air in the summer.

Heat from the earth is transferred through a system of underground or underwater pipes. The heat from the earth is then delivered through the existing air delivery ductwork, just like conventional heating and cooling systems. The GHP systems are not only used in residential areas but also in factories, schools, and office buildings.

Benefits of Geothermal Heat Pumps
A GHP system is the most energy efficient, environmentally clean, and cost-effective form of space conditioning available, according to the Environmental Protection Agency (EPA). GHPs can lower utility bills from 25 to 50 percent and in addition to its cost effectiveness, offers quiet operation, free or reduced-cost hot water, and improved comfort.

System maintenance is minimal (occasional cleaning of the heat exchanger coils and regularly changing the air filters keeps the system running).

Unlike any other heating and cooling system, a GHP can provide free hot water. The water is heated with a device called a "desuperheater," which transfers excess system heat to the hot water tank. In the summer, hot water is provided virtually free; in the winter, water-heating costs can be cut in half.

System Installation
There are four basic types of ground loop systems. Three of these—horizontal, vertical, and pond/lake—are closed-loop systems. The fourth type of system is the open-loop option, which can be installed in existing groundwater wells. The best option for a home depends on the climate, soil conditions, available land, and local installation costs at the site. The most common option for ground source heat pumps is the closed loop, in which pipe is buried horizontally at 4-6 feet deep or vertically at 100 to 400 feet deep. The pipes are filled with an environmentally friendly antifreeze/water solution that acts as a heat exchanger. To discuss which option is best for your home, contact a qualified installer or call your local utility company.

Cost
Because it uses less electricity to move heat rather than create it, installing a GHP system can save a homeowner a considerable amount of energy and money. According to the U.S. Department of Energy, homes that replaced their electric heating systems with GHP systems saved about 42 percent on their energy bills for heating, cooling, and water heating.
Roy Goettig, the executive director for the Iowa Heat Pump Association, says that there are many factors that together determine the cost of the GHP system.

"Any heating contractor that just throws out an estimate is not doing his job," Goettig said. He feels that a contractor needs to consider the ductwork, the size and the style of the home before estimating a price. He also suggests to new homeowners that the higher price of the unit will pay for itself and is one comprehensive price, where conventional systems may not include the cost of everything needed.

“ One difference between a geothermal and another system is the cost of the loop, which is generally $3,400 to $5,000," Geottig said. "If somebody was borrowing money for that additional cost, the savings on energy bills would pay that additional monthly payment for the loan and put some money back in their pocket."

A house that has heating and cooling bills of $1,500 per year with an electrical or gas system can expect to pay around $700 per year with a GHP system, according to Goettig. He adds that the utility price gap between a geothermal system over conventional heating and cooling systems will widen as electrical and gas costs rise, meaning even more savings for the GHP system user.

"The fact that energy is so important in our lifestyles, and taking a look at the world picture, using a cleaner energy source and not relying on oil or a product out of your control is incredibly important," Goettig said.

Homeowners should check with their local utility and ask if they offer any rebates, financing, or special electric rate programs. Many GHP systems also carry the Energy Star® label which can now be financed with special Energy Star® loans from financial institutions. Ask a contractor about Energy Star® loans or call the Energy Star® toll-free hotline at 1-888-STAR-YES for a list of financing options.

More Information and Additional Resources
Additional information can be found by contacting Roy Goettig, executive director of the Iowa Heat Pump Association at www.iaheatpump.org, the Energy Efficiency and Renewable Energy Network at www.eren.doe.gov, the Geoexchange Web site at www.geoexchange.org, the Environmental Protection Agency at www.epa.gov, and U.S. Department of Energy at www.energy.gov.

Additional information on home energy savings can be found on the Iowa Energy Center’s Web site, www.energy.iastate.edu or by calling (515) 294-881

The Iowa Energy Center is a nonprofit organization dedicated to increasing Iowa's energy efficiency and the use of renewable fuels.

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