Cooperative Living September 2016 - 28

EnergySense | by Pat Keegan and Amy Wheeless, Contributing Writers
Is a geothermal heat pump right for you?
D
Upgrading to a more efficient HVAC system is a great way to reduce your monthly energy bill.
ear Pat: I am planning to
replace my current heating
system with a geothermal
heat pump. It is pricey compared to
other options, but it seems like an
efficient option, and I like the fact
that it includes air conditioning.
Would a geothermal heat pump be a
good choice for me? - Ralph D.
Dear Ralph: In most areas of the
U.S., space heating and cooling
account for a large percentage of
overall home-energy use, so
upgrading to a more efficient HVAC
system is a great way to reduce your
monthly energy bill. A geothermal
heat pump, also known as a groundsource
heat pump, is among the most
efficient types of heating and cooling
systems you can consider installing in
your home.
Even when it is extremely hot or cold
outside, the temperature a few feet below
the surface of the ground remains
relatively constant and moderate. A
geothermal heat pump system uses this
constant ground temperature to help
heat and cool your home. As a result,
geothermal heat pumps are quite efficient.
For example, according to the U.S.
Environmental Protection Agency,
geothermal heat pumps use up to 44
percent less energy than traditional airsource
heat pumps, and up to 72 percent
less energy than electric-resistance
heaters combined with standard
air conditioners.
A geothermal heat pump system is
made up of three main components:
* The collector, or loop field, which is in
the ground and cycles a liquid, like
antifreeze, through dense plastic
tubing;
* The heat pump that is in your home;
* The duct system that distributes
the heated or cooled air throughout
your home.
26 | Cooperative Living | September 2016
A geothermal heat pump can have many
different connections to the ground.
may be possible. The loop field is
connected to the heat pump and
then placed at least 8 feet below the
surface of the water. If a homeowner
has access to a pond that is
sufficiently wide and deep, this
option can be the lowest cost.
Geothermal systems typically cost
During the winter, the collector absorbs
the heat stored in the ground and the
liquid carries that heat to the heat pump,
which concentrates it and blows it into the
ductwork, warming your home. In the
summer, the heat pump extracts heat
from the home and transfers it to the
cooler ground.
The collector that exchanges heating
and cooling with the ground can be set up
in one of three main ways:
* Horizontal system: Plastic tubing is
placed in trenches 4 to 6 feet below the
surface of the ground. This system
works well when a home or business
has sufficient available land, as these
systems may require up to 400 feet of
trenches to be dug.
* Vertical system: If the site does not
have sufficient space for a horizontal
system, a collector can be placed
vertically. In this system, a drill digs
100 to 400 feet below the surface and
places the tubing. This system can be
more costly than a horizontal system,
but will have less impact on any
existing landscaping and can be used
on smaller lots.
* Pond system: If a home has access to a
pond or lake, a pond system (also
known as a water-source heat pump)
more than other heating systems,
largely because of the collector and
the associated digging or drilling, but
their high efficiency can help reduce
the payback time. The cost will vary
based on whether new ductwork is
needed and the type of collector you
install, among other factors. However,
there are incentives available for those
who install qualified geothermal heat
pumps. Most notably, there is a 30 percent
federal tax credit for installing an ENERGY
STAR-rated system before the end of 2016
- so, if your system and installation cost
$20,000, you could take $6,000 directly off
your federal tax bill. Some states also offer
tax incentives, and your electric co-op may
offer rebates or financing to help you pay
for the system.
For those with high energy bills
resulting from heating and cooling, an
efficient geothermal system is a good
option to consider. In addition, those
building new homes should consider at
the outset whether to install a geothermal
heat pump. With new construction, the
system can be included in the mortgage
and installing it before the home is
completed means no disruption to your
landscaping.
Talk with a qualified energy auditor
who can help you evaluate the different
heating and cooling options that would be
best for your home. 
This column was co-written by Pat Keegan and
Amy Wheeless of Collaborative Efficiency. For
more information on geothermal heat pumps,
please visit: www.collaborativeefficiency.com/
energytips.
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Cooperative Living September 2016

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