Get a copy of The Smart Guide to Geothermal for more FAQs and a wealth of information for homeowners, builders and architects.
EXCERPT FROM THE BOOK: THE SMART GUIDE TO GEOTHERMAL
Can one geothermal system provide both heating and cooling for my home?
Yes. One of the advantages of a GHP is that instead of two separate systems, one push of a button on the thermostat switches from heating to cooling.
Can a GHP be installed in new homes as well as older homes?
Yes. GHP systems are being installed every day in new construction as well as in older homes.
What are the options for earth loops?
Earth loops fall into two categories: open loop and closed loop. Open loops take water from a pond or well, extract the heat and then return it to the same or another location. New water is constantly being used. Horizontal closed loops circulate water in underground plastic pipes, extracting the heat in a continuous operation that uses the same water. Vertical closed loops send the water into vertical bore holes and then return it to the GHP. DX or Direct Exchange systems use copper piping instead of plastic and send the refrigerant through the ground and back. Instead of having a separate ground loop and refrigerant loop, they are combined into a single loop. See chapters 4 and 5 for details.
What are the advantages and disadvantages of these various configurations?
Open loops are generally less expensive because there is less trenching. Horizontal closed loops require more available land space. Vertical bore holes require less space, but are more expensive to drill. DX systems are usually more efficient and require less ground space since the holes are drilled at angles from a central point. Chapter 7 has additional information.
Can I install my own geothermal system?
Yes, if you are a certified, trained and experienced installer. Otherwise, forget it. Read chapter 15 for why this is important.
How much space should I allow for the interior equipment?
The floor footprint of the heat pump is about the same as a refrigerator, but ductwork and piping can double that.
How can a GHP heat my domestic water?
A desuperheater is an optional add-on with a separate heat exchanger that can provide excess heat to your hot water tank. Chapter 10 describes this plus other methods of obtaining hot water.
Is a geothermal heat pump noisy?
No, a GHP is very quiet, especially compared to fossil fuel burners with their abrupt, noisy start up while sucking in huge amounts of air.
Are GHPs safe?
Well, they are a little hard to steal. Sorry, could not resist that. The lack of any combustion means no flames, no noxious gases. They are as safe as your refrigerator.
Can a GHP be connected to an existing radiant system?
Absolutely, and also to an existing hot water system, or a hot air system. This can save considerable expense. Radiant or hot water will not permit heat pump air conditioning, of course.
Will an underground horizontal loop affect my landscaping and lawn?
With horizontal trenches, yes, but only for a week or so. The grounds will soon be back to normal. It is also possible to bore underground horizontally if your contractor has the proper equipment. This reduces the impacted area considerably. See chapter 4.
What level of maintenance is required?
Very little maintenance is needed. There is no outside equipment, as with an air conditioner; no annual tune-ups or nozzle replacement, as with an oil burner; and no chimney to clean. Air filters need replacement as with any air delivery system. Water filters need cleaning if you have an open-loop source.
How do I determine how efficient my GHP unit is?
Look for the Energy Star label or go to your manufacturer's web site. The Coefficient of Performance (COP) indicates heating efficiency. Your unit should have a COP of 3.3 to 3.6 or greater. Mine is 4.1 and that means it is 410% efficient. Chapter 18 provides much more information including definitions about GHP efficiencies.
How much does a GHP cost?
Buying a heating/cooling GHP system is not like buying a refrigerator off the shelf. Each installation is unique and calculating cost requires a qualified contractor. Chapter 12 provides more details. Visit manufacturers' websites for their online savings/cost calculators.
Will a GHP reduce my living expenses?
A GHP will significantly cut your annual heating/cooling costs every year. In addition, the costs to maintain the system will be lower.
What financial incentives are provided?
Substantial US federal incentives provide a tax credit of 30% of the cost for GHP systems, but these tax credits are set to expire in 2016. Your state or power company incentives can be found online at www.dsireusa.org. Canadian incentives can be found at www.oee.nra.gc.ca. More information can be found in chapter 13.
What is a typical payback period for a GHP system?
Payback is defined as the time in years that it takes to recover the added costs of a GHP compared to a standard heating plus cooling system. It can range from zero to 5 years or more. Chapter 14 explains more.
Does a GHP increase the value of my home?
Yes, it does; the EPA has stated that it increases $20 for every dollar of energy saved. If you save $2,000 per year by not buying fuel oil or natural gas, the increase in your home's value will be $40,000. Please refer to chapter 8 for a more rigorous discussion of this.
How long will a geothermal system last?
A geothermal heat pump can last 20 to 25 years, much longer than a standard oil burner.
Do geothermal systems have warranties?
GHP manufacturers offer equipment warranties, varying from 1 to 5 years, or more. This is one criteria for judging/selecting a manufacturer. Appendix C lists manufacturers in the US and Canada along with their warranties. In addition, you should get an installation warranty from your local installer.
How does geothermal energy benefit our environment?
This is important and should be well understood. All other methods of heat/cooling your home use up energy sources that are not renewable or produce pollutants into the atmosphere. A GHP emits no pollutants on-site and uses energy in the earth that is continually renewed by nature.
See more FAQs in the book, The Smart Guide to Geothermal