How Do You Heat A House With Geothermal?
What is Geothermal Energy?
Geothermal energy is energy generated from heat stored in the Earth. The geothermal energy used for heating comes from just below the Earth’s crust and is considered a renewable energy source. There are three main types of geothermal energy systems used for heating:
- Direct geothermal – Uses hot water directly from a geothermal reservoir brought up through a well.
- Direct-use – Uses hot water from an aquifer directly to provide heat.
- Geothermal heat pumps (GHPs) – Use stable ground or water temperatures near the Earth’s surface to control building temperatures.
The Earth’s interior remains a constant 50–60°F throughout the year. A geothermal heating and cooling system taps into this resource by circulating water or a water-antifreeze solution through pipes buried in the ground. In winter, the fluid collects heat from the Earth, bringing it indoors to warm the air. In summer, the process runs in reverse, taking heat from the air and transferring it back into the ground.
Benefits of Geothermal Heating
Geothermal heating systems offer many benefits over traditional heating methods like furnaces and heat pumps. Some of the top advantages of geothermal heating include:
- Higher Efficiency – Geothermal systems are over 3 times more efficient than the most efficient gas furnace. This is because geothermal heating taps into the constant temperatures of the earth, which act as a massive thermal battery.
- Lower Energy Bills – The high efficiency of geothermal heating means you’ll use much less energy to heat your home, resulting in utility bill savings of up to 60% annually.
- Reduced Carbon Footprint – Geothermal systems reduce reliance on fossil fuels for heating. This allows homeowners to minimize their carbon footprint and environmental impact.
- Tax Incentives – The U.S. government offers tax credits and rebates for installing an ENERGY STAR certified geothermal system, helping offset the upfront costs.
With benefits like drastic energy savings, renewable operation, and available tax incentives, geothermal heating is one of the most advantageous ways to heat a home sustainably.
How Geothermal Heating Works
Geothermal heating systems use the earth’s natural underground heat to provide energy efficient and environmentally friendly heating and cooling for homes and buildings. Here’s an overview of the main components and how they work together:
Underground Loops – Long pipes are buried vertically or horizontally underground to access the earth’s constant temperature. A liquid solution circulates through the pipes absorbing the underground heat.
Heat Pump – The liquid solution travels back above ground into the heat pump unit. Here, a heat exchanger transfers the absorbed underground heat to refrigerant in a vapor compression cycle, amplifying the temperature.
Heat Exchanger – The refrigerant then passes through a heat exchanger, which transfers its gained heat to water or air.
Distribution System – Fans and ductwork distribute the heated air or water is pumped through radiators to heat up rooms in the home.
The process works in reverse for cooling – extracting heat from indoor air and transferring it through the underground loops back into the earth. This allows geothermal systems to provide efficient heating and cooling from a free and renewable resource.
Types of Geothermal Systems
There are two main types of geothermal systems used for heating homes – open loop and closed loop. The type used depends on the geological conditions of the land where the system is being installed.
Open Loop Systems
Open loop systems take advantage of underground reservoirs of water. They pump water up from a well to extract heat, then discharge the water back underground after running it through a heat exchanger. These systems are only viable where there is an abundant supply of groundwater that can be sustainably used.
Closed Loop Systems
Closed loop systems recirculate an antifreeze solution through pipes buried underground. The pipes either run vertically in holes bored into the ground or horizontally in trenches. The antifreeze solution extracts heat from the earth as it circulates.
Vertical Loop
Vertical loop systems have pipes that extend 300-400 feet straight down into the ground. This takes up less surface space but requires deeper drilling. Vertical loops are used where land space is limited.
Horizontal Loop
Horizontal loop systems have pipes buried 4-6 feet below the surface, coiled in horizontal trenches up to 400 feet long. More yard space is required for the trenching, but less deep drilling is needed. Horizontal loops are generally more cost-effective for residential installations.
Installing a Geothermal System
Installing a geothermal heating and cooling system is a complex process that is best left to experienced professionals. While it may be theoretically possible for a homeowner to install their own ground loop, the excavation, piping, and integration into the home’s HVAC system is not a DIY project.
It’s highly recommended to hire a qualified geothermal contractor to handle the entire installation. They will pull the required permits, properly size the ground loop and geothermal unit to your home’s heating/cooling demands, oversee the ground loop installation, connect the piping into the home, and integrate the system with your existing HVAC ductwork and controls.
The permitting and regulations for geothermal systems vary by municipality. Many areas require both plumbing and HVAC permits, as well as inspections at certain stages of the installation. Your contractor will be familiar with the local permitting procedures and codes.
Sizing the ground loop field is a critical part of the installation, as an undersized loop will lead to inefficient system performance. The loop field needs to be large enough to exchange heat with the ground over many heating and cooling cycles for many years. Proper sizing depends on climate, soil type, loop piping layout, and the home’s energy needs. Advanced simulation software is used to optimize the loop field design.
Installing the underground loop piping involves trenching or horizontal directional drilling to place the pipe at the proper depth. The piping is pressure tested before backfilling the trenches. Then the system can be connected to the home’s HVAC equipment and water source heat pump or geothermal unit. Proper installation is key to maximizing performance and lifespan of a geothermal heating and cooling system.
Cost of Geothermal Heating
The upfront cost of installing a geothermal heating system can be quite high compared to conventional HVAC systems. Installation costs can range from $10,000 to $30,000 depending on the size of your home, the type of geothermal system, and the complexity of installation. However, there are several factors that help make geothermal heating affordable.
Many federal, state, and local governments offer incentives in the form of tax credits, rebates, and financing options to make geothermal more affordable. These incentives can cover 30% to 60% of the upfront costs. The federal government offers a 26% tax credit for installing a geothermal system. Many states and utilities also provide additional incentives.
While the installation costs are high, geothermal heating can provide huge long-term savings. The underground loop system has a long lifespan of over 25 years with minimum maintenance. Once installed, geothermal systems provide heat and cooling at remarkably low operating costs, providing 70% to 80% savings on annual heating and cooling bills compared to conventional systems.
With the energy efficiency, government incentives, and long-term savings, most homeowners find that the upfront investment in geothermal heating pays for itself within 3 to 10 years. Going geothermal provides great value and allows you to reduce your environmental footprint.
Maintenance of Geothermal Systems
Like any heating system, geothermal heat pumps require some regular maintenance to keep them operating efficiently. Overall, geothermal systems tend to require less maintenance than traditional systems like gas or oil furnaces. However, there are a few key maintenance tasks that should be performed annually.
One of the most important maintenance items is checking the antifreeze level and mixture. Geothermal systems rely on a water and antifreeze solution flowing through pipes underground. The antifreeze helps prevent the pipes from freezing in cold weather. The antifreeze level and concentration should be checked once a year and topped off if needed.
Ensuring proper water flow is also crucial for maintenance. The pumps and pipes in a geothermal system can accumulate mineral deposits over time that restrict water flow. Flushing the pipes annually helps remove buildup and ensure the system runs smoothly. Flow meters can also be checked to make sure the water is moving at the proper rate.
In addition to antifreeze and water flow, the air filters, backup heating elements, and ventilation should be inspected regularly. Technicians can perform annual check-ups to clean and calibrate parts and identify potential problems. With proper maintenance, a geothermal system can provide decades of reliable, efficient heating and cooling.
Is Geothermal Right for You?
If you’re considering installing a geothermal heating system for your home, there are a few factors to weigh:
Home size and layout
Geothermal systems work best for heating larger homes with an open floor plan. The stored heat in the ground can more easily be distributed throughout a spacious home. Geothermal may not make sense for very small homes.
Climate and soil
The climate where you live and the soil conditions on your property will impact the efficiency of a geothermal system. Areas with temperate winters and summers are ideal. Soil with high clay content is best for conducting heat into the ground loops.
Budget
While geothermal systems can save on energy costs long-term, the upfront installation cost is quite high, often $20,000-$30,000. Make sure you can recoup the installation costs within 5-10 years through energy savings.
Environmental goals
Geothermal heating is an eco-friendly, sustainable option. If you want to reduce your carbon footprint, geothermal is one of the greenest heating solutions available today.
Top Geothermal Heating Brands
The geothermal heating market has become increasingly competitive over the years as more manufacturers offer innovative products and expanded lines. Here are some of the top brands to consider when shopping for a geothermal heating system:
ClimateMaster
ClimateMaster is one of the leading geothermal heat pump manufacturers in the industry. They offer comprehensive geothermal and water-source heat pump systems for residential and commercial buildings. ClimateMaster’s product lines include the Trilogy Series, Tranquility Series, and TMW Series. They back their geothermal heat pumps with warranties up to 10 years on parts and labor.
WaterFurnace
WaterFurnace has over 30 years of experience specializing in geothermal and radiant heating and cooling systems. They manufacture a wide selection of geothermal heat pumps including the Envision Series, 7 Series, and 5 Series. WaterFurnace products come with warranties up to 10 years on parts and labor.
Bryant
Bryant offers ENERGY STAR certified geothermal heat pumps as part of their Evolution System line. Available models include the Preferred, Legacy, and Vision. Bryant geothermal systems are backed by 10-year parts and labor warranties. They also provide strong dealer support.
Carrier
Carrier’s geothermal heat pump offering is the Carrier Infinity Series which includes the Greenspeed variable capacity technology. Their systems come with warranties up to 10 years on compressor and coil parts. Carrier has an extensive network of dealers to facilitate installation and maintenance.
When evaluating top brands for a new geothermal heating system, be sure to consider the product range, features, warranties, and dealer network coverage in your area. This can help narrow down the selection to the best option for your home’s heating and cooling needs.
Future of Geothermal Heating
Despite geothermal heating already providing tremendous benefits in terms of efficiency, cost savings, and environmental sustainability, the future still holds much promise for further growth and maturation of the technology.
With increasing concerns over rising energy costs and climate change, analysts project strong and steady growth for geothermal heating systems in the coming years. The global geothermal heating market is expected to expand at a compound annual growth rate (CAGR) of 5.3% from 2022-2027, reaching a total market size of $130 billion by 2027 according to research firm Global Market Insights.
Several key factors are contributing to this bright outlook:
- Consumer awareness – As more homeowners learn about geothermal benefits, adoption rates increase.
- Government incentives – Rebates and tax credits in many regions help offset geothermal installation costs.
- Technology improvements – New techniques and equipment lead to greater efficiency and lower operating costs.
- Economies of scale – As demand rises, costs per unit decrease.
In terms of innovation, companies are making steady advancements such as more sophisticated heat pump designs, hybrid geothermal systems, and integration of geothermal with other renewable energy sources and smart home platforms.
There are still challenges, like the high upfront installation expense. But new financing options combined with rising energy prices are making the long-term payoff more compelling. And for new construction, geothermal systems have a clear cost advantage versus traditional HVAC.
Overall, geothermal energy is positioned to play an expanding role in building a clean energy future and reducing the impacts of climate change globally.
