The Basics of Geothermal

Geothermal heating (known as Ground Source Heat Pumps, or GSHP’s) at its most basic is just transferring heat energy between the Earth and your home. In the winter when you need to heat, you simply transfer the heat from the earth into your home. In the summer when you need to cool, it is just the opposite; heat is taken from your house, and put back into the earth.

Geothermal systems can be installed basically anywhere, and have no need for natural hot springs or geysers under your house. This system just uses a heat exchanger in the earth to transfer the heat energy.

The United States E.P.A. has called ground source heat pumps.

“The most energy efficient, environmentally clean and cost effective space conditioning system available.”

Geothermal systems provide highly efficient, clean, quiet and renewable heating and cooling at a very low cost.

The bottom line is a geothermal heating system will save you thousands of dollars per year on heating costs. No longer with you have to worry about the volatility of heating fuel costs and availability. No longer will you be worried about the environmental affects of heating your home.

The value added to your home from a renewable heating system is also a great bonus.

Geothermal heating is clean, cheap and efficient heating in almost any situation.

Geothermal Heating Explanation

Heating Process

Geothermal heating simply pumps heat from the earth into your home. A liquid is circulated through a large loop(s) in the ground called a ground loop. While that liquid is traveling through the pipe buried in the ground, it absorbs the heat from the surrounding ground. That liquid then carries the heat to the heat pump, which acts similar to a refrigerator in taking that heat through a refrigerant cycle inside the heat pump, and discharging it to your home heating distribution system (forced air or radiant floors).

Cooling Process

Geothermal cooling works the same as geothermal heating, except in reverse. Heat is taken out of the structure in the home, put into the circulating liquid inside the ground loop, and absorbed into the cool earth. This “reversed” cycle is simple to switch a heat pump into with its reversing switch. When a ground source heat pump is in cooling mode it is functioning the same as a refrigerator, pulling heat out of the house, putting it through a refrigerant loop, and then expelling it out. A refrigerator does that using the coils on the back. A GSHP does it using the large earth loop and cool mass of earth, making it more efficient to have heat go to cold instead of hot ambient air.

Water Heating

As a by-product of the natural function of the heat pump, hot water can be produced for the domestic hot water load of the household. Using a “desuperheater” addition to the heat pump, you are able to capture the excess heat from the compressor that may otherwise be lost in the cabinet of the heat pump, and pump it straight into your home’s hot water heater. This helps reduce costs of heating the hot water tank, which can directly save you money.

Ground source heat pumps can also be configured with a dedicated hot water coil for on demand water heating. This double walled heat exchanger differs from a desuperheater in that it operates when there is a “call” for heat from in the domestic water tank.

For most residential applications where there is a lower domestic hot water load the desuperheater is the more economical choice.

In applications where there is a significant domestic water heating loads the dedicated hot water coil can be considered.


General Cost

Like most things, the cost of the whole thing is the bottom line deciding factor. But direct initial costs cannot be the only comparison.

Geothermal systems will usually cost more to install initially, but will easily pay themselves off over time just in money saved from cheap operation. The typical payback period we are seeing is usually 3-6 years, depending on your situation.

Huge federal and state discounts are available specifically for these systems, and when paired with a renewable energy loan, can potentially cost you no extra money per year to install and heat with a geothermal system, AND pay back the loan. All of that for the same cost of just heating your house with a conventional system.

The value added to your home from a renewable heating system is also a great bonus.

Geothermal heating is clean, cheap and efficient heating in almost any situation.

Energy Savings

The operating costs of a geothermal system are roughly 1/3rd of the operating costs of a traditional heating system. So instead of paying $3000 per year to heat your home, you could be paying around $1000.

With the renewable system, you are using ‘free’ energy directly from the earth, and the only operational cost is the electricity needed to transfer that energy from the earth into your home.

The instant the geothermal system is installed, it saves a significant amount of money over the conventional system.

Geothermal Tax Credits

Now is the absolute best time to take advantage of huge tax credits for geothermal heat pumps.

There is currently a 30% federal tax credit towards the installation of a ground source heat pump in a residence. Thats money straight off of your taxes.

There is also many state rebates and incentives for ground source heat pumps, and they can all be found at the DSIRE website.

Renewable Energy Loans

With the large stimulus recently passed by the federal government, there is an abundance of money set aside by state programs for renewable energy loans. These loans are becoming more and more readily available, and are offered at low fixed rates. With the energy savings associated with geothermal heating, the principal and interest of the loan can be paid, and then some. Many homeowners are enjoying a geothermal heating system without the large upfront fee, and are still in the positive with money while paying back the principal and interest on the loan.

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