Geo Thermal has been in the building industry long enough
for there to be solid results on how these heating and cooling systems
are working in ultra energy efficient homes. We have multiple houses that use
geo thermal systems for heating and cooling just as we have multiple houses
that use conventional and hybrid heating and cooling systems. Because of an
increased interest in geo thermal systems lately, I thought that I would put my
thoughts together and let everyone have access to them.
In the past, I would always be against geo thermal systems in the
houses that I designed and built because of how little those systems would run
in the types of homes that we were building. Another reason that I would be
against the geo thermal systems is because our HVAC subcontractors would always
say, "What do you want to use for the supplement heat?". I have a
problem with that. Apparently, the geo thermal systems that our 'subs' were
installing around the state would not work below about 28 degrees Fahrenheit,
well, let me rephrase that, the systems would switch functions at about 28
degrees. Inside of geo thermal units, there are electric elements that will
heat the air or liquid depending on what type of heating system the house has
(forced air/radiant heat?). That is why the 'subs' would ask what supplemental
heat source we wanted, because using the 'onboard' electrical elements in geo
units gets very pricey. One of our past homeowners who has geo thermal in his
house told me that he had an $1,800 electric bill during a cold month a winter
ago because his geo thermal unit heated his house with the onboard electrical
element.
So why is there still so much hype over geo thermal? In my
opinion, because it is a cozy blanket/warm feeling for people buying a house in
a time when energy prices are unstable. A recent conversation that I had with a
potential client opened my eyes to the opinion I just gave. The potential
client ask another builder about building an energy efficient home and the
builder said, "Well, we put geo thermal in all of our houses." The
builder became confused when asked further about what made the house energy
efficient. Putting geo thermal in a conventional 'production builder' house may
make sense, because a propane fired furnace would cost a fortune to run in a
house like that. I don't know enough about the house in question to form any
other opinions. The point is, a
'hot button' is not always the best fit even though everyone is always
mentioning it.
I will go on record as saying that geo thermal has its place in
the building industry and may or may not be the best fit for any particular
project. As I said to someone recently, .."the
answer to the question of if geo thermal is the best fit for your project is
like a law question, it depends." Science
is what dictates what is used in house. As I mention in my book 'Build
Green, Make Green, Save Green', I feel that Newton's Third Law of
Motion (..This means that for every force there is a reaction force that is
equal in size, but opposite in direction. That is to say that whenever an
object pushes another object it gets pushed back in the opposite direction
equally hard. )(Rice University) can be applied in its own way to a house.
Meaning, that whomever is building the house must remember that for everything
they do to a house, whether it is insulation or installing a wood burner, that
something else will occur as a result of that installation. Mold and mildew is
an example of this point, so is indoor air quality. Another example is
something I hadn't considered a while back. A person I knew well told me that
his father built an Insulated Concrete Form (ICF) house a while back and that
he wanted to pick my brain. I said "OK", and he started to tell me
that his father's house had a weird, almost 'septic' smell to his house. I
asked if there was an air exchanger in the house and this guy said, "No,
he just opens the windows a little bit to get the house to breath." Would
anyone ever think that make up air could come through plumbing vents? That is
what was causing the 'septic smell' in his father's house. Equal and opposite
force. Also, opening windows in the winter to get the house to 'breath' kind of
defeats the purpose of having such a tight exterior envelope if you ask me!
When I am designing a house and getting ready to estimate the cost of the house, I always have multiple heating systems figured for that house. By doing this, we can see which system will be the best pay back for the house. We have houses that are Platinum Certified LEED for Homes houses that have natural gas fired boilers, propane fired boilers or natural gas fired forced air furnaces. We also have used propane fired forced air furnaces in several of our houses because we have found that those heating systems don't run very hard in the homes that we build and don't cost very much to run.
I am certainly not bashing geo thermal companies or people that
want or have these heating and cooling systems. I am simply giving my input
based on multiple case studies of houses that we have built. Whenever I hear or
see an email of someone asking about geo thermal, my first response is in the
form of a question, "Tell me why you are thinking about using geo
thermal". Sometimes people get defensive, so I will follow up my question
saying something like, "there is no right or wrong answer, I am just
trying to understand more about what you want and need." Recently, I met
with a potential client who mentioned geo thermal and she answered my question
about geo thermal in her own way. I asked her a follow up question that sounded
something like, "what do you heat with now, what does your current house
use as a heating source?" Her reply was, "this house is all electric,
but we always heat with wood, using the wood burner downstairs.." Again,
another follow up question, "Do you want a wood burner in your new
house?" To which, she replied, "definitely". Had she replied,
"No, burning wood is too much work for us..", then I would have asked
further questions about what fuel sources were available and geo thermal to see
if the system may be a good fit for them. Instead, knowing that they want to
heat with wood means that the heating system that we would install in their new
house would basically be supplemental heat until such time as they no longer
wished to heat with wood, which could be 20 or more years into the future.
Are you tracking so far? Good. My point in all of this, is that
there is much discussion and 'scientific-ness' that goes into selecting the
parts of a house, heating and cooling systems included. That is why I always
called our houses 'Hybrid Homes', because of the origin of the word hybrid.
Latin for hybrid is mulus which translate to mule. A mule is the first hybrid
in recorded history and dates back to the ancient Romans who combine a donkey
and a horse. This combination of a donkey and a horse had to be very specific
or else the offspring would not be a mule nor be able to function as a mule,
which was the reason the ancient Romans would go through all the trouble of
tracking down these specific animals. For the record, the correct combination
for creating a mule is a male donkey and a female horse.
As you can see, you can still combine components to create
something else, but in order to have the outcome turn out as the designer or
builder intended, the combination of components has to be correct to not create
an unfavorable result. This is normally the case in the building industry and
thankfully more builders are catching on and understanding the importance of
what goes in to a house.
In closing, I will continue to say that geo thermal has its place
in building. In fact, if anyone reading this can explain geo thermal better,
than please do in the comment section. I want to learn more about why people
are so interested in geo thermal if the system is so limited.
Thank you for reading, stay tuned for more entries coming soon..
AB
