Geothermal Energy Facts
Answers to Popular Questions

Geothermal heating and cooling uses renewable ground source energy derived from heat deep in the Earth’s crust. For every 100 meters you move below ground, the ground temperature increases approximately 3 degrees Celsius. Geothermal heating and cooling uses the abundant supply of natural and stable energy stored in the Earth for homes and business properties.

Geothermal Facts and Statistics

  • According to the EPA, replacing an ordinary HVAC system with geothermal is the environmental equivalent of planting 750 trees
  • The U.S. General Accounting Office estimates that if geothermal systems were installed nationwide, they could save several billion dollars annually in energy costs and substantially reduce pollution
  • Today there are more than 1,000,000 geothermal installations in the United States
  • Geothermal systems represent a savings to homeowners of 30 to 70% in the heating mode and 20 to 50% in the cooling mode, compared to conventional systems
  • Surveys consistently show that more than 95% of all geothermal system owners would recommend it to a friend
  • Geothermal heat pumps strengthen U.S. energy security. For every 100,000 homes using geothermal HVAC, the U.S. reduces its foreign oil consumption by 2.15 million barrels a year
  • Schools using geothermal systems in the U.S. are saving a combined $25 million dollars a year in energy expenses and are putting those funds into better equipment, books, computers, and more teachers
  • Geothermal systems produce no on-site emissions
  • Geothermal units are stored indoors, so there are no outdoor units creating heat and noise. They are also protected from the elements.
  • Geothermal units have no chemical byproducts, therefore greatly reducing the risk of carbon monoxide poisoning in your home or gas leaks
  • Every 100,000 homes with geothermal heat pump systems reduce foreign oil consumption by 2.15 million barrels annually and reduce electricity consumption by 799 million kilowatt hours annually
  • According to the EPA, geothermal systems are the most energy efficient, environmentally friendly, and cost-effective comfort systems available.

General Geothermal Heating & Cooling Questions

How does Geothermal Energy Work?

The temperature in St Louis fluctuates all the time through the changing seasons. The ground temperature that is four to six feet below the ground surface remains relatively constant all year long. The Earth absorbs around 40% – 60% of the heat from the sun, making the earth a giant solar panel. During the geothermal installation process, Hoffmann Brothers installs polyethylene pipes or loops underground by digging wells. The pipes are filled with a water solution and sealed using heat fusion. These loops run from the ground into your home to your geothermal heat pump.

How does Geothermal Energy Work in my Home or Business?

  • Whether you have a horizontal, vertical, or lake closed-loop Geothermal system, your Geothermal heat pump is going to treat the earth as an energy reservoir for heating and cooling your home; during the hot Summer months, your geothermal system will remove the heat from your home or business and transfer that heat into the earth via your closed-loop system. During the cold winter months, your geothermal heat pump will utilize your closed-loop system to take the heat energy stored within the earth and move it into your home or business.
  • Geothermal systems are extremely quiet. You don’t have an outdoor air conditioner that rattles or vibrates in the summertime when you are trying to enjoy the outdoors. The Heat pump is installed within your home or business and operates quietly and efficiently to maintain a comfortable indoor climate.
  • Geothermal heating and air conditioning systems do not use fuel to run. Geothermal heating is flameless and, therefore, produces no health and safety concerns that come with burning fossil fuels. The US Department of Energy (DOE) along with the Environmental Protection Agency (EPA) have named geothermal systems the most environmentally friendly way to heat and cool your home.
  • Because geothermal heat pump systems are so efficient, much less energy is required to heat and cool your home or business. This reduced energy requirement often means that less fossil fuels will be consumed to maintain a comfortable indoor climate. The Environmental Protection Agency (EPA) estimates that geothermal systems can reduce energy consumption- and corresponding emissions- up to 44% compared to air-source heat pumps. Furthermore, the EPA estimates up to 72% reduction in energy consumption when compared to electric resistance heating from standard HVAC equipment.

What Is A Geothermal Heat Pump?

A geothermal heat pump is an electrically-powered device that uses the Earth’s natural heat storage ability to heat and cool your home or business at significantly less energy costs.

How Efficient Is A Geothermal Heat Pump?

The geothermal heat pump is one of the most efficient residential heating and cooling systems available today, with heating efficiencies 50 to 70% higher than other heating systems and cooling efficiencies 20 to 40% higher than available air conditioners. That directly translates into savings for you on your utility bills.

How Long Will My Geothermal System Last?

Geothermal units are durable and highly reliable. The geothermal heat pumps contain fewer mechanical components, and all components are either buried in the ground or located inside the home, which protects them from outside conditions. The underground pipe carries up to a 50-year warranty.

How Noisy Is The Geothermal Heat Pump Unit?

Geothermal units are very quiet, providing a pleasant environment inside and outside of the home. Geothermal units have no noisy fan units to disturb outdoor activities, on or near the patio.

How Safe Are Geothermal Heat Pumps?

Geothermal systems are safe and protected. With no exposed equipment outdoors, children or pets cannot injure themselves or damage exterior units. Geothermal heat pumps have no open flame, flammable fuel or potentially dangerous fuel storage tanks.

What About Comfort Of Geothermal Systems?

A geothermal system moves warm air (90-105(F)) throughout your home or business via standard ductwork. An even comfort level is created because the warm air is moved in slightly higher volumes and saturates the building with warmth more evenly. This helps even out hot or cold spots and eliminates the cold air blasts common with fossil fuel furnaces.

How Effective Is This Underground System?

The buried pipe, or ground loop, is the most recent technical advancement in heat pump technology. Recently, new heat pump designs and improved buried pipe materials have been combined to make geothermal systems the most efficient heating and cooling systems available.

Are Geothermal Systems Guaranteed?

Nearly all geothermal heat pump system manufacturers offer a warranty for major components that is equivalent to the warranties for conventional heating and cooling systems. Manufacturers of plastic pipe used for ground loops warrant their products for 50 years.

Can These Systems Be Used For Commercial, Industrial, Or Apartment Requirements?

Yes. Many geothermal systems are being installed using a multitude of systems hooked up to an array of buried vertical or horizontal loops. This simplifies zone control and internal load balancing.

What Are The Advantages To An HVAC Dealer?

Geothermal systems create a huge retrofit market not subject to wild fluctuations in housing construction. There is also ample opportunity for stable growth benefiting the dealer and his employees. In addition, these systems are relatively maintenance-free, requiring only regular filter changes. This means fewer maintenance and support calls. There is no outside equipment, so wear and tear is less.

Geothermal Savings and Costs Questions


If you replace your standard heating and cooling system with a high efficiency Geothermal heat pump system, you stand to realize tremendous savings in your utility bills by reducing fossil fuel and electricity consumption.

How Will I Save Money With A Geothermal Heat Pump?

Geothermal heat pumps save money, both in operating costs and maintenance costs. Investments can be recouped in as little as three years. There is positive cash flow, since the energy savings usually exceeds payments on the system. There are also tax incentives as well. See our Rebates & Incentives page for more details.

How Much Does A Geothermal System Cost?

The initial investment for geothermal systems is greater than that of a conventional system. However, when you consider the operating costs of a geothermal heating, cooling and water heating system, energy savings quickly offset the initial difference in purchase price.

Are There Geothermal Tax Credits?

Tax credits! If you choose to install a geothermal heating and cooling system in your home, you are eligible for a tax credit equal to 30% of the total installation cost. So in addition to the monthly energy savings you will realize with your high-efficiency Geothermal System, you will receive a 30% credit on the upfront installation costs of your home system. Geothermal systems installed within commercial properties are eligible for a federal tax credit equal to 10% of the total installation cost.

How Long Will The Geothermal Pipe Loop Last?

Geothermal systems use the industry standard high-density polyethylene pipe. This pipe is often times guaranteed by the manufacturer to be free from leaks for 55 years and is expected to last beyond 100 years. To learn more about the different pipe loop installations, visit our geothermal loop installation page.

What Other Costs Are There Besides The Geothermal System?

You can expect an installation charge for any electrical work, ductwork, water hook-up, and other provisions or adaptations to your home that are required. Your installer can estimate these costs in advance.

How Would Increased Use Of Geothermal Systems Affect Electricity Costs And Availability?

The reduced peak load requirements would allow utilities to serve more customers and to lower fixed costs per customer, thus offsetting some increased variable costs. This would result in less cost per kilowatt, since fixed investment for new capacity is high.

Geothermal Heat Pump Installation Questions

How Much Space Does A Geothermal System Require?

The geothermal heat pump unit inside the home is about the same size as a traditional heating and cooling unit. Most of the rest of the installation is buried underground so it depends on which system is used.

Can Geothermal Systems Be Used For Commercial Buildings Or Apartment Complexes?

Yes, multiple systems can be installed by hooking them up to an array of buried vertical or horizontal loops, thus simplifying zone control and internal load balancing.

Are Geothermal Heat Pump Systems Difficult To Install?

Most units are easy to install, especially when they are replacing another forced-air system. This is known as a retrofit. Geothermal heat pumps can be installed in areas unsuitable for fossil fuel furnaces because there is no combustion and thus no need to vent exhaust fumes. Ductwork must be installed in homes without an existing air distribution system. Your dealer or installer can assess the cost of installing ductwork.

Can I Install A Geothermal Heat Pump System Myself?

It’s not recommended. Thermal fusion of the pipe, drilling and trenching are procedures best handled by licensed professionals. Non professional installations may result in less than optimum performance, which could cancel out anticipation savings.

How Far Apart Are Trenches And Vertical Boreholes Spaced?

Trenches are spaced four to five feet apart while boreholes are spaced ten to fifteen feet apart.

How Long Does It Take To Install A Horizontal Geothermal System?

This depends on soil conditions, length and depth of pipe, and equipment required. A typical installation can be completed in one or two days.

How Long Does It Take To Install A Vertical Geothermal System?

With the vertical installation, time varies with conditions on the site such as type and depth of the overburden, type and hardness of the bedrock, and the presence of aquifers. Typical drilling times are one or two days; total installation can usually be accomplished in two days.

What Are The Advantages And Disadvantages Of The Horizontal And Vertical Installations, Respectively?

Horizontal installations are simpler, requiring lower cost equipment. However, they require longer lengths of pipe due to seasonal variations in soil temperature and moisture content. Since a horizontal heat exchanger is laid out in trenches, a larger area is usually required than for a vertical geothermal system. Where land is limited, vertical installations or horizontal installation can be ideal. If regional soil conditions include extensive hard rock, a vertical installation may be the only available choice.

Vertical installations tend to be more expensive due to the increased cost of drilling versus trenching, but since the heat exchanger is buried deeper than with a horizontal system, vertical systems are usually more efficient and can get by with less total pipe. Your geothermal contractor at Hoffmann Brothers will be able to help you decide which configuration best meets your specific needs.

Geothermal Environmental Questions

How Do Gshps Protect The Environment?

GSHP systems conserve natural resources by providing climate control very efficiently-thus also lowering emissions. GSHPs also minimize ozone layer destruction by using factory-sealed refrigeration systems, which will seldom or never have to be recharged.

What Are The Environmental Benefits Of GSHP Systems?

Currently installed systems are making a huge difference in our environment! The systems are eliminating more than three million tons of carbon dioxide and is equivalent of taking 650,000 automobiles off the road. GSHP systems conserve energy and, because they move heat that already exists rather than burning something to create heat, they reduce the amount of toxic emissions in the atmosphere. They use renewable energy from the sun, and because the system doesn’t rely on outside air, it keeps the air inside of buildings cleaner and free from pollens, outdoor pollutants, mold spores, and other allergens.

Geothermal Questions Concerning your Home

Will My Existing Ductwork Function With My New Geothermal System?

Yes, in most cases. Hoffmann Brothers will be able to determine ductwork requirements and if any minor modifications are needed.

Will An Underground Loop Affect My Lawn Or Landscape?

No. Research has shown that loops have no adverse effects on grass, trees, or shrubs. Most horizontal geothermal installations require trenches about six inches wide. Temporary bare areas can be restored with grass seed or sod. Vertical geothermal loops require little space and do not damage lawns significantly.

I Have A Pond Near My Home. Can I Put A Geothermal Energy Loop In It?

Yes, it is recommended that the pond contain a minimum of eight feet of dept at its lowest level during the year and have ¼ to ½ of an acre of surface area.

My Yard Contains Many Shade Trees. Will This Affect Ground Temperature And My Ability To Use It As An Energy Source?

Not at all, the geothermal system is installed deep enough that it utilizes constant ground temperature.

Can I Put The Loop Under My Septic System?

This practice is discouraged. The geothermal earth loop may drop below freezing in the winter and could damage your septic system.

If The Geothermal Loop Falls Below Freezing, Will It Hurt The System?

No, the antifreeze solution in the loop will prevent freezing down to approximately 15 degrees F. Hoffmann Brothers uses Environol or methanol as the antifreeze.

Can A Geothermal Heat Pump System Be Added To My Fossil Fuel Furnace?

Yes. Called dual systems, they can easily be added to existing furnaces for those wishing to have a dual-fuel heating system. Dual-fuel systems use the geothermal heat pump system as the main heating source, and a fossil fuel furnace as a supplement in extremely cold weather should additional heat be needed.

Will I Have To Add Insulation To My Home If I Install A Geothermal System?

Geothermal systems will reduce your heating and cooling costs regardless of how well your home is insulated. However, insulating and weatherizing are key factors in gaining the maximum amount of savings from any type of heating and cooling system.

How Does A Geothermal Heat Pump Also Heat Water For My House?

Using what is called a desuperheater, geothermal heat pumps can save you up to 75 percent of your water-heating bill by pre-heating the water. When the geothermal system is operating, it pulls water from the water heater and circulates it through a heat exchanger and returns the warmed water back to the tank. Some geothermal models can provide all of your hot water needs on demand at the same high efficiencies of the forced air models.

Can One Geothermal System Provide Both Space Heating And Cooling For My Home? And What About Heating Hot Water?

Yes, a geothermal heat pump can be a combination heating, cooling and hot water heating system. You can change from one mode to another with a simple flick on your indoor thermostat. Using a desuperheater, some geothermal heat pumps can save you up to 50% on your water-heating bill by preheating tank water.

How Does A Geothermal Heat Pump System Heat Water For My Home?

Using what is called a desuperheater, a geothermal heat pump turns waste heat to the task of heating hot water. During the summer, when the system is in cooling mode, your hot water is produced free as a byproduct of the thermal process. In winter, with the heating mode, the desuperheater heats a portion of your hot water. Desuperheaters are standard on some units, optional on others. Stand-alone systems that will heat water all year can be purchased.

How Much Space Does A Geothermal Unit Require?

Most of the geothermal system installations are underground. Inside the house, the heat pump units are about the same size as a traditional heating and cooling unit.

What are the Advantages of Geothermal Energy? – Geothermal Energy Pros and Cons

  • Geothermal Systems remain in operation for an average of 20-24 years. That is an average life cycle 5-11 years greater than Standard HVAC systems which typically last 13-15 years. Unlike standard HVAC systems, Geothermal heating and cooling systems remain unaffected by seasonal temperature extremes because the earth surrounding the geothermal closed-loop system remains at a constant 55 degrees Fahrenheit regardless of whether the outdoor temperature is 100 degrees or 0 degrees.
  • Your Geothermal Heat Pump can use the heat taken out of your home to provide your home with hot water- at no additional energy cost. With a Geothermal heating and cooling system, you can expect to receive approximately 60-80% of your hot water for free during summer.
  • A typical electric furnace will produce 1 watt of heating energy for every 1 watt of electricity put into the system. On the other hand, if you put 1 watt of electricity into your Geothermal heat pump, your Geothermal system will pull an additional 3 watts of energy from the earth via your closed-loop system resulting in 4 watts of heating energy for every 1 watt of electricity consumed- that is 400% energy efficient!