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When I bought my home back in 2005 it came with a typical HVAC system which had a large unit placed by the side of the house.

Around 2009 this HVAC system was starting to show its age and I decided I wanted to upgrade the unit to better serve the heating and cooling needs of my home.

When I was researching replacement units I came across the concept of using geothermal energy as a more efficient way of air conditioning.

The more I read about using geothermal energy, the more I became intrigued.

It did not take long before I decided that my new system would be a geothermal unit.

Geothermal concept.

With a typical HVAC system, the main unit is placed outside (the units are often quite noisy and take up a decent amount of space prohibiting indoor installations).

The air being drawn into the system is therefore the same as the outdoor temperature.

This introduces a large amount of energy inefficiency.

The delta between the outdoor temperature and the desired indoor temperature can be quite large.

When it is hot outside the HVAC unit is drawing hot air in.

A large amount of energy is then required to convert this heated air to your desired indoor temperature, which is accomplished by running that air through the coolant system.

In the winter, when outdoor temperatures drop, you are introducing cold air into the system.

A large amount of energy is again required, this time trying to raise the temperature of the cold air to a more tolerable level.

Geothermal units are quite elegant by design, taking advantage of the more constant temperature that can be found underground.

There are various geothermal configurations that can be utilized to maximize the efficiency for energy transfer.

Each configuration has its pros and cons.

There may also be constraints for which system can be implemented because of the property itself (either because of property size or lack of any nearby bodies of water).

Because of the natural waterfalls on my property, I knew that my home was sitting on a very large underground aquifer (the majority of the water going over the 50 ft waterfall disappears underground).

I also already had two high volume producing wells that supplied water to the main house and the guest house so I knew a 3rd well could easily be put in.

I therefore opted to implement a vertical open loop geothermal system.

It was quite an impressive feat of coordination between the well drilling company and the HVAC geothermal company.

A 150 ft or so well was drilled near the front of my property (that location was chosen as it was adjacent to a natural spring that originated on my property).

Large PVC tubing was then placed for both the water inflow and outflow of the geothermal system.

The inflow tubing had to be much thicker as the water being actively pumped to the house came with a powerful pressure head.

Because water draining from the system was not pressurized, the outflow piping had much thinner walls.

The system I chose required digging about a 500 foot trench from the front yard along the driveway and towards the side of the house where it entered into the garage to service the two geothermal units I had purchased (one for each floor of the home).

A pump was placed at the well cap which would be called into action whenever the geothermal unit was activated.

Water from deep underground, which was around 50 degrees in temperature, would then enter the geothermal unit, go through a heat exchange, and then return back to my front yard where it would flow into the natural spring (we had a landscaper later make it look like a small stone waterfall to pay homage to the natural surroundings).

The geothermal effect.

Because the water source was a constant 50 degrees in temperature, regardless of the season, there was a much smaller delta between that temperature and my desired indoor temperature.

I typically keep my home at 71 degrees year round.

In winter I would therefore only need enough energy to bring the temperature up 21 degrees from my supply source, far more efficient than raising it 60+ degrees with the old system.

During the summer months my geothermal unit was even more efficient as the water source at 50 degrees by itself was enough to reduce the indoor temp.

To further increase the energy savings, I coupled this geothermal system with a geothermal hot water tank that siphoned off heat from the heat exchange unit during summer months.

I was essentially getting a free heating element for my hot water for a good portion of the year.

Another pleasant side effect of geothermal heating in the winter was that the indoor air did not feel as dry as before.

It is just a guess but I think a standard HVAC system takes a lot of moisture out of the air due to the amount of heating required to bring the temperature up.

Cost savings.

I am very lucky that my electric company provides relatively cheap electricity to my area, about 10 cents/KWh. 24/7.

Even with the low utility costs, I still did notice a savings from my monthly utility bill, with about a 15-20% savings during the summer months and about 10-15% during the winter months.

The entire system cost me about $35k to install, which was definitely more expensive than if had I gone with a standard system.

However I was able to take advantage of the government green energy program and ended up getting a tax refund of almost $8k.

The timing of my refund check could not have happened at a worse time, however.

It just so happened that I was in the beginning of my divorce in 2010 and when I had to file my taxes my now ex would not agree to signing off on the paperwork unless any tax refund would be put into an escrow account for the judge to later decide how to divide it.

Well that refund was indeed deposited into the escrow account and the judge promptly decided to award her the full amount (this was unfortunately a recurring theme throughout the divorce).

So the savings I anticipated when choosing a geothermal system vanished and my ex benefited instead.

Even without this tax rebate, I am happy with my decision to go with geothermal.

 

 

Note:

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-Xrayvsn