The underground temperature remains steadier than surface air, so channeling outdoor air through subterranean channels into a home can yield more cooling in summer and warmer conditions in winter. Depending on the setting, this approach can dramatically cut or even eliminate energy use for heating and cooling. Geothermal air conditioning offers a reliable option during energy shortages and remains an environmentally friendly and affordable choice.
Canadian wells, also known as Provence wells, illustrate geothermal air conditioning as a growing method due to its straightforward setup.
These systems involve pipes placed beneath the building and connected to regulate interior temperatures. They do not require electrical power for operation, so the primary upfront cost is installation, after which heating and cooling bills are significantly reduced as energy savings accumulate.
The core idea behind Canadian wells is simple: during summer, air stored in underground ducts stays cooler than indoor air, while in winter the underground air is warmer than the air inside the house. This natural heat exchange can warm spaces in winter and cool them in summer without relying on electricity.
Bioclimatic strategies like this substantially boost building energy efficiency. While installation is cheaper when included in new construction, the benefits are evident in any retrofit or new build.
The surface temperature tracks environmental conditions, but at depths of two to three meters it remains relatively constant. At this depth, temperatures commonly hover around 18C to 24C, as noted by environmental sources.
Its layout involves laying channels two to four meters deep and about 35 meters long underground to circulate air. The air exchanges heat with the surrounding soil as it travels through the ducts before being delivered to living spaces, with or without supplemental heat input.
It is estimated that a stable year round temperature exists around fifteen to twenty meters below the surface. At shallower depths, roughly three meters, temperatures closer to optimum comfort for homes can be found.
Soil assessment is recommended before installation
The soil profile is analyzed to determine thermal conductivity and other properties to evaluate full potential and possible drawbacks.
Soil conductivity relies on porosity and saturation. Granular soils with clay or silt conduct heat more readily than sandy soils. Clean sandy soils show low conductivity when dry but improve significantly when saturated. Water content strongly influences thermal properties, including conductivity and heat capacity.
In winter
Outside air is cold, but at depths of two to three meters, underground temperatures remain higher than the surface. When outdoor air travels through underground pipes, it warms, improving indoor conditions and potentially reducing or eliminating electric heating depending on circumstances.
In summer
Outdoor temperatures rise above the underground level, so air passing through underground ducts cools and reaches living spaces a few degrees lower, increasing comfort and reducing or avoiding the use of air conditioning.
Reference information is available from reputable sources on how to implement a Canadian well, with practical guidance and case studies to illustrate results.
Additional sources provide practical insights into soil conditions, system design, and long term performance. For a deeper read on implementation considerations and real-world outcomes, practitioners often consult technical literature and field reports attributed to building science portals and climate research bodies.