FAQ
Frequently Asked Questions:
Geothermal
Systems
Q: How does a geothermal system work?
A: The earth's temperature, a few feet below the surface, varies only slightly year round. Temperatures range from about 45º in northern latitudes to about 70ºF further south. By taking advantage of these constant temperatures, a geothermal system provides extremely efficient heating and cooling. In winter, the pipes (ground loops) that are buried underground circulate a fluid which absorbs heat from the earth. The fluid then carries the heat into the home where the geothermal system uses a heat pump to concentrate the earth's thermal energy. Then, to fill the interior or your home with warmth, the resulting air is circulated through standard ductwork. This process is reversed in the summer. In your home, the heat is removed from the air and is transferred through the heat pump to the ground loop piping. This excess heat is carried back to the earth by the fluid in the ground loop. The minor amount of electricity used to operate the ground loop pump and fan is the only external energy needed for a geothermal system.
Q: How efficient are geothermal systems/ground source heat pumps?
A:
By tapping the earths energy to get its power, geothermal systems are one of today's most efficient heating and cooling systems. With a heating efficiency about 60% higher and a cooling efficiency about 30% higher than today's heating and cooling units, ground source heat pumps are able to save you money on your utility bills.
Q: Has the geothermal technology been around long?
A: In recent years, with many improvements being made in the materials used, the installation methods, and the efficiencies of the compressors, pumps and other equipment, geothermal technology has been making its way into mainstream use. However, many homeowners have been enjoying the the benefits of a geothermal system for much of the 20 plus years that the basic technology has been around.
Q: What about comfort and safety?
A:
During cold winter months, a geothermal heat pump system uses a standard duct network to move warm air throughout your home producing a very even comfort level. This even comfort level is achieved by moving the warm air in slightly higher volumes. Therefore, it saturates the air more evenly. This eliminates the cold air blast that is typical with fossil fuel furnaces. Ground source heat pumps are very quiet, providing a pleasant environment inside and outside. There are no noisy fan units to disturb outdoor activities. With no exposed equipment outdoors, children or pets cannot injure themselves or damage exterior units. These systems are well protected and safe with no open flame, flammable fuel, or potentially dangerous fuel storage tanks. It also completely eliminates a potential source of poisonous carbon monoxide within the home. Finally, you, the customer, have the peace of mind knowing you're being environmentally responsible by reducing your energy consumption while using an inexhaustible energy source--the earth.
Q: How much does a system like this cost?
A: A geothermal system for the home will cost more than if you bought the typical heat furnace and central air conditioning system. However, with more contractors offering geothermal systems and the industry developing innovative ways to install these systems faster and more efficiently, the installation costs have declined greatly in recent years and are expected to continue to fall. To get an accurate comparison of the costs you need to consider a few things:
- How long it takes to recover the difference in costs between the two systems. Payback for geothermal heat pump systems can run anywhere from two years to six years depending on many things including amount of its use, how well your walls are insulated, and the tempature outside. Heating and cooling costs for a typical 2,000-sq.-ft. home can run as low as $1 a day.
- The savings from heating, cooling, and domestic hot water must be combined to get an accurate picture of total energy savings.
- Maintenance costs on a geothermal system tend to be quite lower than the typical house a/c and heating system due to the system's reliability. With all components located inside the house/building or buried in the ground, these systems are highly durable.
Q: Can I get tax credit for installing this system?
A:
Depending on where you live, some states and providences do have tax credits for installing geothermal systems. Texas offers customers rebates on solar water heaters and energy-efficient equipment, such as heat pump water heaters, heat recovery water heaters, and package air conditioners and heat pumps. Austin Energy’s revenues fund The Home Energy Air Conditioning and Appliance Rebate Program and also offer a Home Energy Loan Program. Check with your electric utility provider, Department of Commerce, or Ministry of Revenue for further information.
Q: Can these systems be used for commercial buildings or apartment complexes?
A: Yes, multiple systems can be installed by hooking them up to an array of buried vertical or horizontal loops, thus simplifying zone control and internal load balancing.
Q: How much space does a geothermal system require?
A:
The ground source heat pump unit inside the house is about the same size as a traditional heating and cooling unit. Most of the rest of the installation is buried underground so it depends on which system is used.
Q: Which system is best, open or closed-loop?
A:
The net results in operating cost and efficiency are virtually the same. Which system to choose depends mainly on whether you have an adequate ground water supply and means of disposal. If you do, an open loop can be used very effectively. If not, either a horizontal or vertical closed-loop system is your best choice. Over a period of years, a closed-loop system will require less maintenance because it's sealed and pressurized, eliminating the possible build-up of minerals or iron deposits.
