The underground temperature remains steadier than surface air, so channeling air through subsurface ducts into a home can deliver more cooling in summer and more warmth in winter. Depending on conditions, energy use for climate control can be markedly reduced or even eliminated. Geothermal air conditioning stands as a solid option to offset winter energy shortages, and it is affordable and environmentally friendly.
Canadian wells, also called Provence wells, are a clear example of geothermal air conditioning gaining popularity for its straightforward approach.
These systems involve pipes placed beneath a home and connected to it to regulate interior temperatures. They do not require electrical energy for operation, with installation being the primary upfront cost. After installation, a home’s climate-control bills tend to drop as substantial savings accrue over time.
Typical temperature difference in a Canadian well in winter about home
summer operation about
The principle behind Canadian wells is simple: the air in underground ducts is cooler than indoor air in summer. In winter, the underground air is warmer than the air inside the house. This natural heat exchange provides heating in winter and cooling in summer without additional electricity.
This bioclimatic approach significantly boosts a building’s energy efficiency. It is cheaper to install during new construction, but benefits are clear in any case.
Surface temperature follows environmental changes and remains relatively stable a few meters underground. At a depth of two to three meters, temperatures typically stay steady around 18ºC–24ºC, as noted by the custom portal Abouthaus.
The system lays channels about 2–4 meters deep and roughly 35 meters long, allowing air to circulate and gradually adopt the floor’s temperature before entering living spaces, with or without extra heat input.
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It is estimated that a stable year-round temperature exists around 15–20 meters deep. Around three meters depth, temperatures near ideal comfort levels of 18º–24º are often found in homes.
It is recommended to examine the soil beforehand.
Before installing a Canadian well, the soil is assessed to understand its thermal conductivity and other properties. This helps determine the system’s potential and any possible drawbacks.
Soil conductivity depends on porosity and saturation. For example, granular soils with clay or silt conduct heat more readily than sandy soils. Dry, clean sandy soils conduct less heat, but conductivity rises when the soil is saturated. Water presence strongly influences thermal properties, including conductivity and heat capacity.
In winter:
Winter brings cold outdoor air. At two to three meters depth, the temperature remains higher than outside air. When outside air is circulated through the underground pipes, it warms up before reaching living spaces, potentially reducing or eliminating the need for electric heating depending on the situation.
In summer:
In summer, outside air is warmer than underground air. The air traveling through underground channels cools before it enters the home, improving comfort and lowering or avoiding the use of air conditioning or mechanical ventilation.
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The approach described here is illustrated in more detail at a related resource on how to construct a Canadian well.