| | ![](https://mcusercontent.com/8621257cc44673d2eb28b4eea/images/9aa914d4-149b-e69e-1713-3e61254acb24.png) | Subterra Monthly Blog |
|
|
|
|
|
|
|
|
| “Terraforum” The Pump Divide: Air Source Heat Pumps vs Ground Source Heat Pumps |
|
|
|
|
|
|
|
|
| In the quest for energy efficiency and cost savings, heat pumps have emerged as champions of sustainable heating and cooling solutions. But which is better? Air source heat pumps or ground source heat pumps? Each type comes with its own set of advantages, challenges, and ideal applications. But what sets them apart, and how do they perform in various environments? Let’s delve into the world of heat pumps and uncover the differences of each, while keeping the following question in mind: what should developers, owners, and builders be considering when choosing between air source and ground source heat pumps?
| ![](https://mcusercontent.com/8621257cc44673d2eb28b4eea/images/e235f81a-d538-2cca-660c-aa556db58fda.png) |
|
|
|
|
|
|
|
|
| Understanding the Basics
Before diving into the specifics, let’s brush up on the basics. Both air source heat pumps and ground source heat pumps operate on the same fundamentals of heat exchange using a refrigerant cycle. However, their methods of heat extraction are what set them apart.. Air Source Heat Pumps (ASHPs): Harnessing Atmospheric Heat
ASHPs extract heat from the ambient air outside a building. They work well in climates with mild winters and mild summers, and are relatively easy and inexpensive to install. However, in climates that have summers and winters, such as Chicago, Boston, and New York, ASHPs use a lot of electricity, especially during summer and winter months. ASHPs also require a lot of maintenance because they are exposed to the outside environment. And they are noisy. ASHPs typically have an indoor and outdoor component. The outdoor component is a compressor, which generates a lot of noise. It is common for multi-family residential operators to get noise complaints in the summer and winter due to ASHPs.
| ![](https://mcusercontent.com/8621257cc44673d2eb28b4eea/images/739bc573-3b26-723d-690a-261712e76931.png) |
Ground Source Heat Pumps (GSHPs): Tapping into the Earth’s Stable Temperatures
On the other hand, GSHPs tap into the consistent temperatures beneath the Earth's surface. They use a network of pipes buried underground (typically geothermal boreholes) to absorb or dissipate heat. GSHPs are renowned for their high efficiency, especially in climates that have cold winters and hot summers, as the ground temperature remains stable throughout the year. Overall, it is less expensive to operate GSHPs as significantly less electricity is required for heat exchange. Furthermore, the life cycle is longer since GSHPs are not exposed to outside environmental conditions. Lastly, noise is not a problem since the heavy lifting is performed by the Earth. | ![](https://mcusercontent.com/8621257cc44673d2eb28b4eea/images/40b757df-a7aa-942b-e941-29643ca4f862.jpg) |
Applications: Choosing the Right Fit The choice between ASHPs and GSHPs often comes down to environment and building considerations:
Residential Heating and Cooling: For urban homes with limited drilling area, ASHPs may be the preferred choice since geothermal boreholes are not required. Most of the time, backup heating applications will also be required for residences with ASHPs. For larger properties with ample land or in rural areas, GSHPs are the superior choice due to high efficiency and lower electricity and maintenance costs.
Multi-family Residential Heating and Cooling: In settings where space and energy efficiency are paramount, GSHPs conquer. They can efficiently meet high heating and cooling demands while reducing overall energy consumption and operating costs. They also free up space in the building for additional amenities and architectural design considerations.
Commercial and Industrial Heating and Cooling: GSHPs are the preferred option for large developments, as they free up space and reduce operating costs.
New Construction vs. Retrofits: GSHPs are often favored in new construction projects, as it is usually easier to construct a geothermal borefield before the building is built. The geothermal borefield can even be constructed under the building’s footprint.
Environment: In environments that have year-round mild weather, ASHPs are a good option, even though more maintenance may be required. In cities such as New York, Boston, and Chicago, GSHPs provide the greatest benefit due to the ability to provide steady heating and cooling all year round, even during peak heating and cooling seasons, with little to no strain placed on the electricity distribution system.
| ![](https://mcusercontent.com/8621257cc44673d2eb28b4eea/images/51de1451-5afd-c4f3-2231-90d0a7c14a27.png) | Geothermal Exchange Systems & GSHPs
When talking about ‘Geothermal Energy’, ‘Geoexchange Systems’ or ‘Geothermal Heat Pumps’, we are referring to GSHPs. Although GSHPs are more expensive up-front, they offer greater savings, efficiency, reliability, and are much longer lasting than ASHPs.
Subterra’s solution offers geothermal GSHP systems at no upfront cost to developers and owners. Subterra constructs the geothermal GSHP system, operates it, maintains it, and guarantees its performance. Subterra’s program is structured like a utility, except better – our level of service and guarantees outshine even the best traditional utility providers, and our pricing is competitive, below market, locked-in and transparent.
On top of this, Subterra’s team of experts deliver solutions for all projects, regardless of complexity, from stand-alone high-rise buildings, to district energy systems, master-plan developments, and full campus conversions. We understand that no two off-takers have the same needs. As such, we lead with GSHP, but may tie in other technologies, like ASHPs, waste-energy-transfer systems, controls, and cooling towers to address every aspect of heating and cooling requirements.
| ![](https://mcusercontent.com/8621257cc44673d2eb28b4eea/images/876d1529-f2be-49d9-c365-f8ad3d3b3ff0.png) | The Bigger Picture
The Department of Energy (DOE) has been increasingly advocating for GSHPs over air source heat pumps ASHPs due to their unparalleled efficiency and environmental benefits. GSHP reliability translates into significant energy savings and reduced greenhouse gas emissions over the long term, aligning with the sustainability goals of the DOE. Furthermore, its contribution to load balancing and decongestion of the grid by reducing peak electricity demand has a huge impact on electricity infrastructure and reliability, particularly during peak summer an winter when ASHPs put a burden on the grid due to their high electricity consumption. In a recent study on the potential grid impacts of national-scale mass deployment of GSHPs, the DOE found that GSHPs would reduce national electricity payments by greater than $1 trillion by 2050. For more on the DOE’s ground breaking study, as well as to view the technical report itself here.
Conclusion
In the realm of heat pumps, both air source and ground source variants offer compelling advantages and applications. ASHPs excel in versatility, affordability, and ease of installation, making them a popular choice, but they cost more to operate, maintain, and replace. On the other hand, GSHPs have the upper hand when it comes to efficiency, performance, and ongoing cost savings. Ultimately, the decision between ASHPs and GSHPs hinges on factors such as climate, space availability, budget, and specific heating and cooling needs. Subterra’s offering solves this problem by offering GSHPs as part of a utility model. By carefully evaluating these factors, owners, developers, and builders can make informed choices to achieve optimal resident comfort, lower operating costs, and increase efficiency and sustainability in their heating and cooling systems.
| | FOR MORE INFORMATION, REACH OUT TO:Briana GagliardiMarketing & Communications Manager |
|
|
|
|
|
|
|
|
| | | ![](https://mcusercontent.com/8621257cc44673d2eb28b4eea/images/88b431db-a6fd-04a3-8139-ec184ea265db.png) | | |
|
|
|
|
|