Frequently Asked Questions
How efficient is a GSHP?
The GSHP is one of the most efficient residential heating and cooling systems
available today, with heating efficiencies 50 to 70% higher than other
heating systems and cooling efficiencies 20 to 40% higher than available
air conditioners. That directly translates into savings for you on your
Can one system provide both space heating and cooling for my
home? And what about heating hot water?
Yes. A GSHP can be a combination heating/cooling and hot water heating
system. You can change from one mode to another with a simple flick on
your indoor thermostat. Using a desuperheater, some GSHPs can save you
up to 50% on your water-heating bill by preheating tank water.
How does a GSHP system heat water for my home?
Using what is called a desuperheater, GSHPs turn waste heat to the task
of heating hot water. During the summer, when the system is in cooling
mode, your hot water is produced free as a byproduct of the thermal
process. In winter, with the heating mode, the desuperheater heats
a portion of your hot water. Desuperheaters are standard on some units,
optional on others. Stand-alone systems that will heat water all year
around can be purchased.
How much space does a GSHP unit require?
Most of a GSHP installation is underground. Inside the house, the heat
pump units are about the same size as a traditional heating and cooling
How long will my GSHP system last?
GSHPs are durable and highly reliable. The GSHP contains fewer mechanical
components, and all components are either buried in the ground or located
inside the home, which protects them from outside conditions. The underground
pipe carries up to a 50-year warranty.
How noisy is the GSHP unit?
GSHPs are very quiet, providing a pleasant environment inside & outside
of the home. GSHPs have no noisy fan units to disturb outdoor activities,
on or near the patio.
How safe are GSHPs?
GSHP systems are safe and protected. With no exposed equipment outdoors,
children or pets cannot injure themselves or damage exterior units.
GSHPs have no open flame, flammable fuel or potentially dangerous fuel
What about comfort?
A GSHP system moves warm air (90-105(F) throughout your home or business
via standard ductwork. An even comfort level is created because the
warm air is moved in slightly higher volumes and saturates the building
with warmth more evenly. This helps even out hot or colds spots and
eliminates the cold air blasts common with fossil fuel furnaces.
How effective is this underground system?
The buried pipe, or ground loop, is the most recent technical advancement
in heat pump technology. Recently, new heat pump designs and improved
buried pipe materials have been combined to make GSHP systems the most
efficient heating and cooling systems available.
Are GSHP systems guaranteed?
Nearly all GSHP system manufacturers offer a warranty for major components
that is equivalent to the warranties for conventional heating and cooling
systems. Manufacturers of plastic pipe used for ground loops warrant
their products for 50 years.
Can these systems be used for commercial, industrial, or apartment
Yes! Many GSHP systems are being installed using a multitude of systems
hooked up to an array of buried vertical or horizontal loops. This simplifies
zone control and internal load balancing.
What are the advantages to an HVAC dealer?
GSHP systems create a huge retrofit market not subject to wild fluctuations
in housing construction. There is also ample opportunity for stable
growth benefiting the dealer and his employees. In addition, these
systems are relatively maintenance-free, requiring only regular filter
changes. This means fewer maintenance and support calls. There is no
outside equipment, so wear and tear is less.
How will I save money with a GSHP?
GSHPs save money, both in operating costs and maintenance costs. Investments
can be recouped in as little as three years. There is a positive cash
flow, since the energy savings usually exceeds payment on the system.
How much does a GSHP cost?
The initial investment for a GSHP system is greater than that of
a conventional system. However, when you consider the operating
costs of a geothermal heating, cooling, and water heating system,
energy savings quickly offset the initial difference in purchase
What other costs are there besides the GSHP system?
You can expect an installation charge for any electrical work, ductwork,
water hook-up, and other provisions or adaptations to your home
that are required. Your installer can estimate these costs in advance.
How would increased use of GSHP systems affect electricity
cost and availability?
The reduced peak load requirements would allow utilities to serve
more customers and to lower fixed costs per customer, thus offsetting
some increased variable costs. This would result in less cost per
kilowatt, since fixed investment for new capacity is high.
Does my state offer any incentives for installing a GSHP
Some utilities offer rebates or incentives to their customers who
purchase GSHPs. To see what your state has to offer click
Some manufacturers and companies have cost and/or savings calculators
on their Web sites. Please see our Links
Are GSHP systems difficult to install?
Most units are easy to install, especially when they are replacing another
forced-air system. This is known as a retrofit. GSHPs can be installed
in areas unsuitable for fossil fuel furnaces because there is no combustion
and thus no need to vent exhaust fumes. Ductwork must be installed
in homes without an existing air distribution system. Your dealer or
installer can assess the cost of installing ductwork.
Can I install a ground source heat exchanger myself?
It's not recommended. Thermal fusion of the pipe, drilling and trenching
are procedures best handled by licensed professionals. Nonprofessional
installations may result in less than optimum performance, which could
cancel out anticipated savings
How far apart are trenches and vertical boreholes spaced?
Trenches are spaced four to five feet apart while boreholes are spaced
ten to fifteen feet apart.
How long does it take to install a horizontal system?
This depends on soil conditions, length and depth of pipe, and equipment
required. A typical installation can be completed in one or two days.
How long does it take to install a vertical system?
With the vertical installation, time varies with conditions on the site
such as type and depth of the overburden, type and hardness of the
bedrock, and the presence of aquifers. Typical drilling times are one
or two days; total installation can usually be accomplished in two
What are the advantages and disadvantages of the horizontal
and vertical installations, respectively?
Horizontal installations are simpler, requiring lower-cost equipment.
However, they require longer lengths of pipe due to seasonal variations
in soil temperature and moisture content. Since a horizontal heat exchanger
is laid out in trenches, a larger area is usually required than for a
vertical system. Where land is limited, vertical installations or a compact
Slinky™ horizontal installation can be ideal. If regional soil
conditions include extensive hard rock, a vertical installation may be
the only available choice. Vertical installations tend to be more expensive
due to the increased cost of drilling versus trenching, but since the
heat exchanger is buried deeper than with a horizontal system, vertical
systems are usually more efficient and can get by with less total pipe.
Your GSHP contractor will be able to help you decide which configuration
best meets your specific needs.
How can I be sure the pipe is installed properly?
Use a reputable contractor. Don't be afraid to ask for and use references.
Reputable dealers and loop installers will be happy to give names and
phone numbers for you to call and confirm their capabilities. Find
out where the installer received training, whether he or she is IGSHPA-accredited,
and how many systems he or she has installed. Also, check with your
utility company representative for names of installers. A list of IGSHPA-trained
and accredited installers is available on our website.
Is it advisable to install a GSHP system large enough
to handle my total heating needs?
GSHP systems are generally sized to meet all your cooling needs. Depending
on heating needs, a GSHP system usually supplies 80-100 percent of your
design heating load. Sizing the system to handle your entire heating
needs may result in slightly lower heating costs, but the savings may
not offset the added total of the larger system. Special consideration
should be given to systems in the north where multiple capacity units
should be considered to handle the large variation between heating and
cooling loads. Your dealer/installer should provide a heating and cooling
load calculation to guide your equipment selection.
How do GSHPs protect the environment?
GSHP systems conserve natural resources by providing climate control
very efficiently-thus also lowering emissions. GSHPs also minimize
ozone layer destruction by using factory-sealed refrigeration systems,
which will seldom or never have to be recharged.
What are the environmental benefits of GSHP systems?
Currently installed systems are making a huge difference in our environment!
The systems are eliminating more than three million tons of carbon
dioxide and is equivalent of taking 650,000 automobiles off the road. GSHP systems
conserve energy and, because they move heat that already exists rather
than burning something to create heat, they reduce the amount of toxic
emissions in the atmosphere. They use renewable energy from the sun,
and because the system doesn't rely on outside air, it keeps the air
inside of buildings cleaner and free from pollens, outdoor pollutants,
mold spores, and other allergens.
Do soil freezing conditions create any problems?
Not if a system is properly designed and installed. The three to four
foot depths allow the sun to melt the frozen soil during the summer.
Adequate length per ton capacity prevents objectionable soil movement.
Does this mean that in extremely cold climates additional
heat sources are necessary?
All systems require an emergency back up. Heat pumps can provide all
the heat necessary even in the coldest weather. An economic analysis
by your contractor should dictate what portion of the heat should be
provided by the heat pump and what portion by auxiliary means.
Will my existing ductwork function with this system?
Yes, in most cases. Your dealer or installer will be able to determine
ductwork requirements and if any minor modifications are needed.
Will an underground loop affect my lawn or landscape?
No. Research has shown that loops have no adverse effects on grass, trees,
or shrubs. Most horizontal installations require trenches about six
inches wide. Temporary bare areas can be restored with grass seed or
sod. Vertical loops require little space and do not damage lawns significantly.
My yard contains many shade trees. Will this affect
ground temperature and my ability to use it as an energy source?
Not at all. The system is installed deep enough that it utilizes constant
Can a GSHP system be added to my fossil fuel furnace?
Yes. Called dual systems, they can easily be added to existing furnaces
for those wishing to have a dual-fuel heating system. Dual-fuel systems
use the GSHP system as the main heating source, and a fossil fuel furnace
as a supplement in extremely cold weather should additional heat be needed.
Will I have to add insulation to my home if I install one of these systems?
Ground source heat pump systems will reduce your heating and cooling
costs regardless of how well your home is insulated. However, insulating
and weatherizing are key factors in gaining the maximum amount of savings
from any type of heating and cooling system.