Geothermal heat pumps use renewable energy from the sun, stored in the ground or nearby water to heat and cool a home. Up to 60% of the energy from the sun that reaches the ground is stored their, maintaining a predictable temperature just a few feet below the surface. Rather than use electric or gas, geothermal uses the energy literally stored in your backyard to heat and cool your home without any direct emissions.
The geothermal equipment may be called a heat pump, but don’t be deceived, it provides both heating and cooling. It also may be a much more practical option for your home than you might think. Let’s talk a little about how geothermal works, and how it’s installed.
How does geothermal work?
Geothermal uses a couple different types of piping systems called ground loops, filled with a glycol or methanol solution. The solution is circulated through the ground loop, and transfer heat energy between a home and the ground.
- To heat your home, the solution is cold when it enters the ground loop and absorbs heat from the ground. The warmer solution enters the heat pump to extract the warmth to heat the air that is circulated around the home. The heat extraction cools the solution again, which is circulated back into the ground coil to repeat the process.
- To cool your home the process is basically reversed. Warmer solution enters the ground loop and the cooler ground absorbs heat to make it cooler. The cooled solution enters the heat pump and is used to cool the air in the home. The process of cooling the air warms the solution again and it is recirculated through the ground loop to repeat the process.
The above description is a bit simplified. If you’d like more details check out this interactive illustration of how geothermal heat pumps work over on Bosch’s website.
How are geothermal heat pumps installed?
Without an understanding of the installation options, many people assume geothermal isn’t an option for them because they don’t have enough land. Others assume geothermal is only an option when building a new home. While it is true that installation can be a bit easier during construction of a home, several options exist for installation of the ground loop which makes geothermal work in a wide variety of situations.
The heat pump itself is installed inside the home and is connected to the air ducts. The ground coil can be installed in one of four ways.
- Horizontal ground loop – the pipes are installed in long trenches four to seven feet deep. This type of installation is most common for residential systems.
- Vertical ground loop – the pipes are installed in holes drilled 150 to 400 feet deep. This type of installation is common in commercial and residential areas where space is limited.
- Lake/Pond ground loop – When a space is close to a body of water large and deep enough, the ground loop pipes can be installed underwater typically as a long coil. The system works the same way except the heat exchange is done with water instead of soil.
- Well water ground loop – Under certain circumstances when a large enough well is accessible by the geothermal system, well water may be used in the ground loop. Typically ground loops are closed, meaning the water solution stays inside. Well water ground loops are open systems, meaning the water is pumped directly through the system and back out into the well. The quality of the well water is unaffected by the system.
How much can I save with geothermal?
Alright .. great, so I can install geothermal, now tell me how much I can save. That really depends on a lot of different factors. The good news is Bosch has a savings calculator that you can use to answer this question based on your exact situation.
To give you a taste of the potential savings I ran a scenario through the savings calculator. Based on St. Louis area utility rates, replacing an existing 3 − 15 year old, average efficiency conventional system in a 1500 to 2500 sq ft home can save $514 annually on heating and cooling costs, and reduce energy consumption by 55%.
Incentives to purchase geothermal
Aside from the cost savings and reduced environmental impact that geothermal heat pumps have, there is also a tax credit of 30% of the total equipment and installation costs available. The tax credit is available on geothermal systems installed on or before December 31, 2016. Visit the Energy Star website for further details.
Find out if Geothermal is right for you
Now that you’ve learned more about geothermal, the best way to get started on finding out if it would be a fit for your home is to visit our Geothermal page and request a bid , or call us directly at 636-916-1122. We will schedule free in-home consultation to discuss your needs and answer any questions you may have. As always, thank you for reading.