Common Geothermal Myths

Let’s face it – there’s a lot of bad information out there about geothermal heat pumps! The method and style of geothermal installations in Massachusetts are not necessarily the same as elsewhere in the United States or beyond. Here we hope to clear up some common misinformation about geothermal installations.

This simply isn’t true. A properly designed geothermal system will provide all of the heating and cooling that you need. There is no need whatsoever to install a gas or oil boiler as backup.

99% of our customers completely remove their fossil fuel heating systems.

The drill rig that installs geothermal borings drills right through bedrock. They certainly have enough power to drill through ice.

Trenching in winter can sometimes be difficult. The degree of difficulty depends on your geographic location and ground cover conditions. A few straw bails can keep the frost out of the ground long enough to trench within a small area. In Eastern Massachusetts, the ground usually doesn’t freeze more than a few inches.

Deep snow can be an issue for site access by the drill rig and support vehicles.

Transitioning from a fossil fuel, hot air heating system to a geothermal heating system is sometimes tricky in the winter as the heat may need to be off for 2 or more days and nights. A lot of coordination is required for us to make the transition as quickly as possible. We have encountered many homeowners who choose to tough it out by putting on some extra sweaters! In some cases it’s best to delay the installation until spring.

We have installed over 400 geothermal systems in Massachusetts and there has never been a situation where we haven’t “reached what we needed”. First, it starts with an understanding of how the underground components of a geothermal systems actually work.

Closed loop geothermal systems in Massachusetts are usually installed in 6″ vertical boreholes ranging from 250 to 600 feet in depth. The borehole is drilled right through bedrock which is usually encountered within 0 to 200 feet. Groundwater is typically encountered within this same depth range. During the heating season, these systems depend on heat being transferred from the bedrock and groundwater, through the pipe into the geothermal fluid inside the pipes, and then into the geothermal heat pump in the house. While groundwater improves the heat transfer

properties of the underground portions of the geothermal system, the presence of groundwater is not absolutely critical to the operation of the system.

Space Requirements

Geothermal installations in Massachusetts do not require large swaths of land!

Many people have seen the photos of horizontal installations that can take acres of land. Encountering rocks, boulders and bedrock during digging is a nightmare. We almost always install vertical boreholes using a drill rig. The drill rig is 35 feet long, 9 feet wide and 13 feet tall. It weighs about 70,000 lbs. It is driven on the highway and on any roads that do not have weight restrictions. Most homes need only one to four boreholes. Each borehole is only 6 inches in diameter.

We require a relatively flat piece of land with the approximate dimensions of no less than 20 feet wide and 65 feet long. There can be no overhead or underground utilities or any other obstacles over any section of the drill rig. This means no tree branches, power or cable lines, water, sewer, or gas lines, septic structures, drywells etc.

The Massachusetts Department of Environmental Protection (MA DEP) guidelines dictate certain setback requirements for closed loop geothermal drilling including:

  • 10 feet from property lines
  • 25 feet from septic structures
  • 50 feet from water wells

The state does not have any setback requirements from foundations or underground utilities.

Many towns have more strict setback requirements than the MA DEP so it is best to consult with your local Board of Health and potentially the Conservation Commission which are the local governing bodies over geothermal drilling activities.

If you are not sure whether you have enough space for geothermal drilling, please give us a call at 617-955-0063 for a preliminary assessment over the phone.

Geothermal FAQs

Geothermal heating and cooling is possible through the use of heat pump technology. Heat pumps move heat from one location to another. Examples of heat pumps include:

  • Refrigerators
  • Air conditioning condensers
  • Portable and window air conditioners
  • Freezers
  • Air source heat pumps
  • Dehumidifiers
  • Heat pump or hybrid water heaters
  • Pool heaters

Heat pumps are not a new technology. Geothermal heat pumps have been used for building heating and cooling since the 1940s. In fact, one of the nation’s most documented geothermal system is located in Winchester, Massachusetts.

Our YouTube channel is full of information about geothermal heating and cooling in New England.

Our Geothermal 101 video is a great place to start!

Installations are broken into two parts: indoor work and outdoor work. Retrofits should be expected to take 6 to 8 weeks from start to finish once on-site work begins. Installations in new construction typically take longer due to the coordination and scheduling with other contractors. Each stage of a geothermal installation can be expected to take the following lengths of time but can vary depending on the site:

  • Permitting and Design – 1 Day to 4 Months depending on the town
  • Drilling – 3 to 10+ days
  • Trenching Between Boring and House – 1 to 2 Days
  • Piping Connections – 1 to 3 Days
  • Duct Modification or Installation – 1 day to 4+ Weeks
  • Electrical Connections – 2 to 3 Days
  • Thermostat Set-up, Zoning Control Programming and Start-up – 1 Day

Although EnergySmart has experience installing horizontal ground loops, almost all of our installations are vertical closed loop systems.

There is a common misconception that horizontal trenching is always the cheapest method of installation. In New England, where bedrock is close to the ground surface and there are many rocks (and boulders!), trenching can be difficult and unpredictable. In ideal situations, an experienced excavator can trench 100 to 150 feet per day. The time required to excavate can easily be doubled when difficult conditions arise. If a lot of rocks are present, it may be necessary to line the trench with clean soil in order to protect the pipe from abrasion. Although we take great care to compact the soil after back-filling the trenches, there can be significant settling of the area over time.

Vertical drilling is very predictable. Bedrock (ledge) is not a problem – it is preferable for its heat transfer properties. The drill rig is the same equipment that is utilized to install drinking water or irrigation wells. Depending on conditions, 200 to 300 feet per day or more can be drilled through solid bedrock. The borings are finished three to four feet below the ground surface so there is no evidence of the boring once the area is back-filled. There is no visible well head. Our on-line photo albums have a lot of great pictures showing the drilling equipment used for vertical drilling.

To see how the pipe is installed into a vertical boring, please see our video from a geothermal installation in Winchester, MA.

No! A properly designed geothermal system will provide all of your heating and cooling needs. There is no need to have fossil fuels for heating whatsoever. In many cases, our clients prefer to remove their fuel oil tanks, boilers and/or furnaces. Imagine finally being rid of unsightly tanks and condensers!

Geothermal heating and cooling takes advantage of the constant temperature of the earth. In the summer, heat is extracted from the building and is discharged into the ground. In the winter, heat is extracted from the ground and discharged into the building. The heat is concentrated through the use of a heat pump. Unlike air source heat pumps that work against highly variable air temperatures, geothermal heat pumps both heat and cool using a constant earth temperature. In New England, the ground temperature is approximately 55F year-round at depths greater than 10 feet below the surface.

The table below demonstrates the temperature differences that an air source heat pump and a geothermal heat pump must overcome. Although both technologies are technically heat pumps, the geothermal system experiences a much smaller temperature difference (delta T) than the air source heat pump. The geothermal system, in effect, has to do less work to achieve the desired indoor air temperature than the air source system.

There are three main types of geothermal heat pumps:

Package Geothermal Units Package units (also called water-to-air geothermal heat pumps), are not unlike traditional forced hot air furnaces. The compressor and the blower are inside one cabinet. The duct work is attached to the cabinet similar to a traditional forced air system.

Split Geothermal Units Split units (another kind of water-to-air geothermal heat pump) are split into two separate components. The compressor is in one cabinet while the blower is in another. The two components are connected to each other with a refrigerant line. We often install split units in 2 and 3 story homes.

Please visit our photo gallery to see photos of a geothermal package units and a split units at various project sites.

Hydronic Geothermal Units Hydronic units, (also called water-to-water geothermal heat pumps), can make hot water for radiant floors. Hydronic units usually have one or two water storage tanks connected to them. These storage tanks act as a ‘heat battery’ where hot water is stored until it is needed for floor heating.

How to Make Hot Water With a Geothermal System

Many know that geothermal systems can make domestic hot water but no one seems to understand how it works. Very simply – geothermal systems have a compressor. Whenever the compressor is operating, there is waste heat produced in the refrigeration cycle. That waste heat (superheat) can be used to produce domestic hot water.

This is a nice video that explains how superheat is formed.

The hot water generating component of a geothermal system is called a desuperheater. It is merely a pump and a heat exchanger that is plumbed in such a way so as to carry the waste heat away from the refrigeration cycle and into your water heater. Geothermal systems make hot water in both heating mode and air conditioning mode. A desuperheater does not affect the heat output of the geothermal system in the winter. Geothermal systems have safeguards that prevent the desuperheater from operating when that heat is needed for heating the building.

A little circulator pump pulls water out of the water heater and pumps it through a heat exchanger inside the geothermal unit where it picks up heat. The warmer water is then pumped back into the water heater.

When operating, a desuperheater is capable of producing hot water with a temperature of 130F+. When the compressor is not operating, the geothermal system doesn’t make any hot water. The balance of the hot water needs must be made up with gas, electric, or some other fuel. A geothermal desuperheater will produce about 50% of a home’s annual hot water needs resulting in significant savings over traditional water heating fuels.

The thermostat on the water heater should be set to about 120F. The desuperheater will draw 120F water out of the water heater and heat it to a higher temperature (125F to 130F+). When the desuperheater is not running, the water heater will still remain at 120F by using the conventional energy source.

A desupeheater does not make hot water ‘on demand’ or ‘as needed’. It should be thought of as bonus hot water. It should not be counted on as a sole hot water source. It is not meant to make hot water for radiant floors.

Construction is the ideal time to install a geothermal system for several reasons:

  • The 30% federal tax credit can be applied to the installation.
  • With the available State and Federal incentives, the installation can sometimes be cheaper than high-efficiency ‘conventional’ heating and cooling systems. If more expensive, the incremental price difference pays for itself in only a few years.
  • Landscape repair is not an issue since landscaping is usually done when construction is complete.
  • Eliminate the need to install a gas line, oil tank, or propane tanks for heating.
  • Eliminate the need to locate unsightly condensers, chimneys, or stacks.

Please also check out our many photo albums to see examples of geothermal systems we have installed at new construction projects.

Geothermal systems are good for the environment:

  • No more burning of fossil fuels for heating.
  • Reduce your home’s carbon footprint by 30% to 50%.
  • Eliminate the risk of an oil spill on your property or a gas leak.
  • Minimize your contribution to the urban heat island effect by dissipating heat deep below the ground surface in the summer.
  • Reduce vehicular traffic as a result of fewer oil deliveries to your neighborhood.
  • Maximize the benefits of other renewable technologies like solar PV panels or solar hot water collectors.

Geothermal systems have beneficial financial implications:

  • When financed through Mass Save, operating costs plus the loan payments can be less than what you were paying for oil or propane.
  • No more oil, gas, or propane bills for heating. Heating is now on your electricity bill.
  • The price of electricity is more stable and predictable than the price of fossil fuel.
  • Choose your electricity source for additional savings.
  • In areas without natural gas service, installing a geothermal system can be cheaper than bringing gas service to the house or installing an underground propane tank. Service and maintain only one piece of equipment. One unit does both heating and cooling.

Geothermal systems improve indoor air quality and comfort

  • No carbon monoxide risk because there is no combustion.
  • Fossil fuels are eliminated for heating. Gas and oil vapors are gone.
  • Superior dehumidification during air conditioning season.
  • Winter indoor air is not as dry because combustion is eliminated.
  • High-grade filtration systems or air cleaners can be added.
  • Energy recovery ventilators can be integrated to conserve energy while providing fresh air.
  • Be more comfortable more often by maintaining a constant temperature in your home year-round. Goodbye 10-degree setbacks!

And best of all:

  • Brag to your friends about how low your heating and air conditioning bill is with your new state-of-the-art geothermal system.