what is geothermal?
and cooling is an exchange of heat
with the earth. The actual soil
under the typical building site
has a tremendous ability to store
and release heat. A geothermal system
is a machine designed to use this
ability. There is a basic law of
physics that states; it is more
efficient to move heat that already
exists than to make new heat from
another form of energy. Geothermal
is a concept that puts this basic
law to work for the advantage of
property owners everywhere.
How does a geothermal
The temperature of an object is
a reflection of the concentration
of British Thermal Units (BTU’s).
If we take some BTU’s out,
we lower the temperature. If we
put some BTU’s in, we raise
the temperature. Whenever we take
BTU’s out of something, those
BTU’s have to be put somewhere.
A geothermal system connects the
inside of a building with the earth
beneath it. An exchange of BTU’s
between the two keeps the temperature
inside the building constant and
comfortable. When the temperature
inside a building is too warm, the
geothermal unit takes just the right
number of BTU’s out of the
building to make it cool and comfortable
and puts those BTU’s into
the earth. When the temperature
inside gets too cool, the system
changes direction and removes BTU’s
from the earth and adds those BTU’s
to the inside of the building raising
the temperature just enough to keep
the inside warm and comfortable.
There are currently three ways
that geothermal units connect with
the earth. Two use liquid and one
does not. The two that use a liquid
are “Open Loop and Closed
Loop”. The other is called
Direct Exchange (DX).
How efficient are geothermal
The first part of the answer lies
in how energy efficient a building
envelope is or will be upon completion?
A conventional high efficiency gas
forced air heating system can be
in the range of 92-94% efficient.
This means for every dollar spent
purchasing energy; you get .92-.94
cents worth of heat or energy in
By comparison, a geothermal heat
pump is measured in Coefficient
of Performance (COP), this means
that a heat pump operating at COP
4.0 during the heating season provides
4 units of heat for each unit of
energy consumed. The output heat
comes from both the heat source
and 1kW of input energy. This means,
for each dollar spent on energy,
you can receive a $4 dollar return.
This also means a 3-5 year payback
for most property. With a life expectancy
of between 20-25 years on a properly
designed and installed geothermal
system, returns can be enormous
even without calculating future
energy price increases.
What types of properties
are well suited for a geothermal
The majority of properties will
be a candidate for a geothermal
system. In the past two years, the
Eastern US has had over 50,000 geothermal
heat pump installations. Harvard
University has committed to using
geothermal and other alternative
energy sources on all new structures
and is in the process of retrofitting
existing buildings as well.
What does a geothermal
There are many variables discovered
in the analysis and design phase
of each project that can affect
the final installed price. Each
project, whether a single family
home or a multiple story office
complex begins with a feasibility
study to determine if a geothermal
heating and cooling system is the
right choice. Yes, geothermal is
more of an investment than a conventional
HVAC system. A better question today
maybe; what is the cost of not installing
an alternative energy system?
Earth provides us the food we eat,
the air we breathe and the water
we drink. Energy for transportation,
the lumber and steel to build our
homes and places for work and worship.
Mother earth also gives us the means
to stay warm or cool year around.
Each choice we make carries an investment;
the outcome of our choices will
be felt for decades to come.
How long do geothermal
20-25 years. Loop fields can last
50 years or more. There is no outside
placement of equipment to rust or
hide from view. Much lower
operating maintenance than conventional
systems, with few moving parts.
Is there a best time to
“Go Geothermal”? Yes,
there are several:
– At the design stage for
most building and remodeling projects,
– When replacing a failing
conventional HVAC system,
– and retrofitting of existing
buildings can be commenced at anytime.
What system is best for
my property? What size and what
options should I consider? How much
will I need to invest? How long
of a payback?
You can buy clothing "off
the rack" but a geothermal
system needs to be tailor made for
each property. Consult with fully
trained and certified IGSHPA contractors:
Here to search for a Geothermal
Specialist in your area