Geothermal energy is heat that comes from the subsurface of the earth — a region of the mantel where temperatures range from 45 to 75 degrees Fahrenheit at all times. Geothermal power plants tap into this thermal heat to generate electricity. We can also use this energy to heat or cool homes directly through a residential geothermal energy system.
Residential geothermal systems use a heat pump to exchange heat with the earth to heat a home in the winter and cool it in the summer. These systems have significant environmental advantages. First, geothermal energy is a clean source of energy and the system requires only a small amount of electricity to operate. Also, geothermal energy is accessible 24 hours a day, making it a reliable energy source with an extremely low carbon footprint.
Selecting the best geothermal system for your home depends on your local climate, how much land you have available, and soil conditions. If you’re interested in using geothermal energy in your home, it’s essential to understand the different options available, including closed-loop, open-loop, and hybrid systems.
Closed-Loop Systems
This type of geothermal energy system is the most common, and it typically includes two different loops made of plastic tubing. The first is the refrigerant loop, which is installed inside your home. The second is the water loop, which is typically buried underground.
As the fluid circulates in the outside tubing, the ground heats it. Then, the fluid goes into the home where it exchanges heat with the refrigerant loop. Of the closed-loop systems, there are three varieties to know:
1. Vertical Loop System
In this geothermal system, you install the tubing vertically in the ground. If your property has limited land available — or you want to minimize the impact on your landscaping — this option may be ideal. However, if you live in an area with rocky ground, digging holes between 100 and 500 feet deep may prove too difficult.
Of all the closed-loop systems, vertical systems are considered the most expensive to install. However, the total cost will depend on multiple factors, including environmental factors, regulations, and square footage. Consult with a professional to receive an accurate cost estimate.
2. Horizontal Loop System
For this type of geothermal system, you install the tubing horizontally, which tends to be more effective than vertical installations. However, this requires more land than a vertical system. Plus, with the tubing closer to the surface of the ground — around 3.5 to 6.5 feet — it’s more likely to be affected by weather conditions. Therefore, it’s usually not recommended for homeowners who see long or cold winters.
This closed-loop geothermal system is typically cheaper than its vertical counterpart, making the initial installation more affordable. Contact a professional to learn more about specific land requirements and pricing.
3. Pond/Lake Loop System
Do you have a body of water on your land? If so, you can choose this geothermal energy system, where you install the tubing at the bottom of a pond or lake. The tubing is laid in a coil, also called a “slinky” closed loop at least 8 feet under the water’s surface to prevent winter freezing.
This geothermal system is ideal when it is a viable option because it tends to be less expensive than other installations. The price varies depending on how close the water body is to your home.
Open-Loop Systems
Similar to a pond/lake loop system, an open-loop system requires water via a well or a surface body of water. The liquid gets directed into the tubing and to the heat pump, where the heat is exchanged with the refrigerant loop. Then the water returns to the ground through the well or surface discharge. This option is best for homeowners who have an adequate supply of clean water and can meet all local codes and regulations.
On average, open-loop systems are cheaper to install than closed-loop ones, allowing you to save up to 60% on the costs. Keep in mind, however, that these systems also require more maintenance than other geothermal systems, including filter changes, water softening, and well testing.
Hybrid Systems
Hybrid systems aren’t as conventional as closed- or open-loop systems, but they’re still available.
They take advantage of a combination of geothermal resources, such as standing column wells and cooling towers. These geothermal systems are primarily used for cooling, rather than heating, making them a viable option for homeowners in warmer regions.
Choosing the Right Geothermal System
If you plan to make the switch to geothermal energy, you can realize many benefits. Geothermal heat pumps typically use 25% to 50% less electricity than conventional heating and cooling systems. They are also generally quieter, last longer, and need less maintenance than conventional systems. You can save up to 60% on heating costs and up to 50% on cooling costs each year. Plus, you can take advantage of the federal tax credit to bring down the costs of installation.
Before you make the switch, do your research and decide which type of system is right for you. Closed-loop, open-loop, and hybrid options all come with pros and cons, but each one delivers key benefits for homeowners. Determining which type of system fits your living situation will lead to long-term contentment.
See how a residential geothermal system works in this video from the U.S. Department of Energy:
Feature image by Harrison Haines from Pexels
About the Author
Holly Welles is a home improvement writer and the editor of The Estate Update. Her work on environmental design has been published on Today’s Homeowner, Build Magazine, and other industry publications.