It may seem too early to think about turning up the heating dial when some of us still are hearing the unmistakable sound of the AC compressor coming to life as it furiously works to keep our homes cool. From the Northeast to the West Coast, air conditioning is increasingly common and crucial as multi-day heat waves become more prevalent, pushing people indoors. It’s also costly and consequential for homeowners, their communities and the planet.
Between June and September, the average homeowner spends $719 cooling their homes, an 8 percent increase year over year and a 10-year high. At the same time, heating and cooling homes and buildings can be energy-intensive, accounting for 43 percent of all energy use in the U.S. (Learn more from the U.S. Environmental Protection Agency.) Because most states are still transitioning to a clean-energy grid, they are burning fossil fuels to power these energy-hungry HVAC units. We certainly shouldn’t plan to solve these challenges by using less air conditioning. In fact, the United Nations estimates the amount of electricity consumed for air conditioning could double by 2050.
Geothermal heating and cooling can be a solution, keeping homes cool in Summer and warm in Winter while minimizing costs, environmental impact and stress on the electrical grid.
What Is Geothermal Heating and Cooling?
Geothermal heating and cooling systems take advantage of the consistent temperature below ground to provide heating and cooling to a home or building at very high efficiency. In fact, as the EPA explains, “Geothermal heat pumps are the most energy-efficient, environmentally clean, and cost-effective systems for heating and cooling buildings.” Read more at www.eia.gov/energy explained/geothermal/geothermal-heat-pumps.php.
A geothermal system uses two main components: ground loops and a heat pump.
- Plastic pipes, called ground loops, are installed in the yard and filled with water—mixed with an earth-friendly antifreeze in climates that require it.
- These ground loops are connected in the home to a heat pump, which is placed in the same location as a furnace or boiler—typically, a basement or utility closet.
In Winter, water circulates through the ground loops, absorbing heat from the ground. The heat pump then processes this water, extracting the heat and using it to heat the home. In Summer, the heat pump pulls heat from the air in the home (thereby cooling the home) and sends this heat into the ground loops’ water. The water then is cooled by the relatively colder ground.
Because the heat pump is connected to ground loops, which are isolated from outdoor air temperatures, the geothermal heating and cooling system works very well and efficiently, even when it is extremely hot or cold outside. This is why geothermal heat pumps tend to be most popular in regions that experience temperature extremes.
How Invasive Is a Geothermal System Installation?
The degree of impact the ground loop installation will have on a yard depends on a few factors: the type of ground loops, the type of drill and the site geology. Rural homes with a lot of land may elect to install horizontal loops, which are ground loops installed horizontally about 6- to 8-feet underground. This type of installation can be done using an excavator instead of a drill, so it’s significantly less expensive. The downside is that a large area needs to be excavated and it’s quite disruptive.
Many homeowners elect to install vertical ground loops, which require a drill to create a hole into which the ground loops are installed. The required hole, or bore, is typically around 4 to 6 inches in diameter and 300- to 600-feet deep. The level of impact to the yard is largely a function of what type of drill is used and what the geology is like. A lot of ground water can produce a mess, but many drilling companies take measures to limit the impact to the yard with silt fencing. Dandelion Energy, for example, uses small, track-mounted rigs and dumpsters to catch any mud and water coming out of the hole to limit impact to the yard.
The indoor installation of a geothermal heat pump is similar to any ducted heat pump. Its level of impact on the home is like that of an air conditioner or furnace installation with one crucial caveat: The home’s electrical and ductwork must be able to accommodate the heat pump.
A heat pump installation—air source or geothermal—can trigger a main panel upgrade. This is because heat pumps use more electricity than a furnace or boiler (but they don’t use any fuels and they are much more energy efficient). The issue is exacerbated because heat pumps often come with an electric-resistance heating element used for backup heating if the compressor fails or to supplement the heat pump, which is especially useful with an air-source heat pump because the amount of heat an air-source heat pump can produce at any given time declines when it gets very cold outside. The electric-resistance element and heat pump together require a substantial amount of combined electrical capacity.
Ductwork in older homes also can be undersized for heat pumps. This is because furnaces and boilers tend to produce air around 140 F, whereas heat pumps produce air closer to 100 F. 100 F air is more than adequate to heat a home, but you need to circulate more 100 F air than 140 F air to heat a home a given amount. The ducts must be large enough to accommodate this larger volume of air. Because a larger volume of air must be distributed, homeowners sometimes need to modify their ductwork to accommodate a heat pump. However, Dandelion Energy has created its own geothermal heat pump that can avoid the need for panel upgrades and ductwork modification; learn more on page 17.
air handler.
A Real-world Geothermal Retrofit
Brian and Kasey of Milford, Conn., own a typical Northeastern home, built in 1996 on a 7,400-square-foot lot in a suburban neighborhood. Before they made the switch to geothermal, their home was heated using a gas furnace.
“Our furnace failed in dramatic fashion with smoke alarms; three fire engines; and a much different New Year’s Eve night than my wife, baby and I had planned,” Brian recalls. “I wanted a technology that that was safer and more efficient than the old way of heating and cooling homes.”
Brian and Kasey carefully considered different heating/cooling options. They determined switching from gas to an air-source heat pump would not have made economic sense because the electricity cost to heat their home with an air-source heat pump was more expensive than running a gas furnace. Brian explains: “Only with the added efficiencies of the geothermal ground loop does a heat pump outperform gas furnaces. The math is similar in the Summer because an air-source heat pump operates exactly the same way as my old outdoor air conditioner; there would have been no savings at all. But with geothermal, my cooling costs have been basically cut in half.”
Because of their relatively small yard, a small, track-mounted drilling rig was used to install the ground loop with minimal damage to the yard. The team drilled 1 bore to 371 feet to meet the home’s heating and cooling requirements. Dandelion Energy relies on its extensive proprietary data on the thermal conductivity of the ground around the U.S. This data, along with weather data and information about the home, helps calculate how much ground loop a home needs. Learn more about this process.
Once the ground loops were installed into the borehole, they were connected into the home via a trench. The trench is insulated and filled in as the final step of the outdoor installation. Soon after the outdoor installation is completed, it is impossible to tell that the homeowner has ground loops at all.
The ground loops are run inside the home to the heat pump. Brian and Kasey’s geothermal heat pump is designed to work with ductwork, but there are geothermal heat pumps compatible with radiators and designed to fit into attics. Typically, a homeowner will need one geothermal heat pump to replace each air handler in the home.
Brian and Kasey’s main panel only had 100-amp service, which typically isn’t enough to accommodate a heat pump.
“Dandelion originally assessed our home in 2021, but the design called for a required electrical-service upgrade from 100 to 200 amps. The complexity and added cost of upgrading our buried electric line put the overall project out of reach,” Brian recalls. “When the project was redesigned in 2024, utilizing the new Dandelion Geo heat pump, we were able to keep our existing 100-amp service. We jumped at the chance to finally be able to ditch the gas furnace and our ugly loud outdoor AC unit.” (Learn more about the Dandelion Geo heat pump below.)
The geothermal system has provided the couple with a range of additional benefits. “I work from home in the basement, sitting just a few feet from our heat pump and I love how much quieter it is,” Brian says. “Removing the furnace also eliminated a major source of combustion and the associated indoor air quality concerns.”
The geothermal system also allowed Brian and Kasey to remove bushes they were using to hide their noisy outdoor air-conditioning compressor and use the space as a play area for their children.
Because a geothermal system’s outdoor equipment is buried and is protected from the elements, it has a very long lifespan. The ground loops are typically warranted for 50 years but last longer. This means, once geothermal is installed in a home, that home can access and take advantage of the inexpensive, renewable energy underground indefinitely.
The Time Is Now
The time has never been better for homeowners remodeling or retrofitting their homes to incorporate geothermal heating and cooling.
In addition to state and utility credits and rebates, which vary, the Investment Tax Credit instituted as part of the Inflation Reduction Act of 2022, covers 30 percent of a system installation cost through 2032 with more limited federal tax credits continuing through 2034. When coupled with state incentives and rebate programs exclusively for geothermal heating and cooling, switching to geothermal is now more attainable than ever.
Geothermal Heat Pump Does Not Require Panel Upgrades, Ductwork Modifications
Because main-panel upgrades and ductwork modifications can be invasive and expensive, Dandelion Energy recently launched the Dandelion Geo geothermal heat pump. The Dandelion Geo’s compressor and electric-resistance element share the same electrical circuit, thereby cutting in half the amount of electrical capacity the heat pump requires compared to a typical heat pump. Because Dandelion Geo is a geothermal heat pump, the amount of heat it can produce doesn’t diminish significantly when it is very cold outside, so the full electric-resistance element is never needed while the compressor is engaged. It’s only required if the compressor fails. If a homeowner wants to quickly increase the temperature of the home, the heat pump comes with a small amount of electric resistance that can come on at the same time as the compressor to augment the compressor. The Dandelion Geo produces air up to 120 F, making it more compatible with undersized ductwork, reducing or eliminating the need for ductwork modifications.
PHOTOS: Dandelion Energy
