1910 S. Riverside Drive, Iowa City, IA 52244   Ph: (319) 337-3520 Fax: (319) 338-0157         

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How efficient are geothermal heat pump systems?

Actual efficiencies will depend on a number of factors, but generally speaking, a geothermal heat pump can be between 2 to 5 times more efficient at producing heat than a gas, propane or oil furnace (based on the amount of energy consumed to produce a given amount of heat). For cooling, a geothermal system (30 EER) can be up to 3 times more efficient than an air source air conditioner (10 EER).

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Why are geothermal heat pumps so effective?

Geothermal heat pumps use the ground temperatures as a "source" for heat energy during heating, and use the ground as a heat "sink" during cooling. The earth acts as a giant, free energy battery, providing an endless, renewable source for heating and cooling comfort. Standard heat pumps use outdoor air for heating and cooling. Because the ground temperature is much more moderate and stable than air temperatures, geothermal system operation is much more energy-efficient, especially at extreme outdoor temperatures.

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Are these systems reliable?

Yes. Geothermal units are not subject to some of the same forces that cause wear and tear on other types of systems. And earth loops are installed using a special grade of polyethylene pipe with heat-fused fittings designed to last 50 years or more. 

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What kind of underground loop system is best?

It depends on several factors. Homes on larger lots usually have horizontal loops installed. Smaller lots may require a vertical loop. A nearby pond can also be used. If you have a well water system, that may be an option. Your Bryant ® dealer is trained to determine which loop design is most appropriate for your home. Regardless of the loop system selected, the operating costs are all about the same

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How much space is needed for a closed loop system?

The smallest closed loop design, the vertical loop, may require a space of only 15x15 feet, or a line of 3x45 feet, located at least 10 feet away from the home, and 10 feet from property lines. Horizontal loops require considerably more space.

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How is the unit size and loop design determined?

Bryant dealers use geothermal system design software to determine the most appropriately sized unit and loop for your home. The software takes many factors into consideration including: the heating and cooling requirements of the home, loop type, depth, soil conditions, earth temperatures, outdoor air temperature extremes, local fuel rates and much more. In addition, the software can demonstrate energy costs for a Bryant geothermal system versus another type of heating and cooling system.

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Will the fluid in the loops freeze during a long, cold winter?

No. Antifreeze in the loop fluid eliminates any concerns about freezing.

 

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Can a well be used instead of an earth loop?

Yes. Prior to using a well for a geothermal installation, the water quality must be checked.  Sufficient water volume is needed for the unit, usually about four to nine gallons per minute during operation. A discharge location like a pond or drainage ditch is also required.

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What is the actual efficiency of a geothermal system?

The energy efficiency of a geothermal system is rated by an industry standard known as ARI/ISO 13256-1, which specifies a set of conditions by which efficiency is determined. The rating for heating is Coefficient of Performance (COP). It's a ratio of the amount of energy used to operate the unit compared to the amount of energy output. Bryant's highest efficiency geothermal units have a COP in excess of 4.5 (that's 450% efficient), compared to a high-efficiency air source heat pump with an average seasonal COP around 1.8. The rating for cooling is called Energy Efficiency Ratio (EER). It's calculated by dividing BTUs per hour output into the watts used. Bryant's highest efficiency geothermal units have EERs around 20-32. That's about 2-3 times better than many air conditioners and heat pumps. But because geothermal units are not rated according to the same industry standard as furnaces, air conditioners, and heat pumps, it is difficult to compare, for example, an AFUE and HSPF to COP, or SEER to EER. To get the full energy efficiency story, compare the dollars. Your Bryant dealer can calculate operating cost estimates using Bryant's geothermal system design software.

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Is comfort compromised to get all this efficiency?

No. In fact, geothermal systems can provide exceptional comfort without the “cold blow” from standard air source heat pumps during heating; or short, hot blasts of air associated with some standard efficiency gas furnaces. Geothermal units deliver air at temperatures that provide comfort throughout the house. The Bryant dual capacity units with variable-speed fans precisely match the needs of the home to deliver comfort no matter what the outdoor air temperature is.

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Can the existing duct work and electrical service be used?

Generally, the existing duct work can be used with a geothermal unit without extensive modification. Variable-speed blowers used in many of the Bryant ® geothermal units can compensate for a less-than-optimum duct system. For the electrical supply, a 200-amp service for the home is recommended.

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What about radiant floor heating?

A geothermal system can be designed to provide warm water for radiant floor applications. Bryant's water-to-water geothermal units are much more efficient than today's best boilers.

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Are geothermal systems more expensive to install, and how long does it take for the extra expense to pay for itself?

Geothermal systems are generally more expensive to install than ordinary systems. For replacement installations, the added cost can be recovered faster than you think, due to the high energy efficiency of geothermal. In a new home where the added cost of the system is included in the mortgage, the monthly energy savings may be greater than the added cost, providing the homeowner with a positive cash flow from day one. Because every situation is somewhat unique, your Bryant dealer can demonstrate the complete financial scenario for your home using the geothermal system design software. Many homeowners find that a Bryant geothermal system is a great investment.

source: www.bryant.com 

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