Air conditioning and home heating are responsible for a considerable share of our CO2 emissions. In densely populated areas, emissions can also make a significant difference to outdoor temperatures - combined with those from transport and other human activities. As Europe seeks to move towards decarbonisation,
sustainable alternatives to high-impact heating and air-conditioning systems are being discussed, particularly when it comes to new buildings or the renovation of historic ones.
The best option so far are so-called Canadian wells or Provençal wells, which can be described as a passive technique to regulate the temperature of a building, using the earth's natural geothermal energy.
How do Canadian wells work?
This type of temperature regulation system is based on the fact that the temperature of the earth at a depth of about 1.5 to 3 metres is more or less stable between 12° and 14° throughout the year. This type of thermal inertia means that the corresponding soil layers are either cooler or warmer than the surface, depending on the season
. Canadian wells consist of underground pipes through which air circulates. The same pipes pass through the building, so that the air in them can be used to heat or cool the dwelling naturally and without burning any fossil fuels.
Canadian wells are particularly effective when there is a significant difference between outdoor and indoor temperatures. The term Canadian wells is used more to refer to the use of geothermal energy as a heating system, while the term Provençal wells is preferred when talking about the same system applied to the cooling of buildings in hot climates.
Pros and cons
In addition to being completely sustainable and natural, Canadian wells are also relatively easy and non-invasive to install, making them ideal for older buildings.
The fact that air is the thermal conductor used by this type of system makes it extremely safe: even if a system breaks down or leaks, no pollutants will seep in and contaminate the ground - something that happens, for instance, when other liquid conductors are used, to achieve better control of temperature variations.
On the other hand, these systems are very complex and expensive to install and allow less flexibility in controlling the internal temperature. However, in terms of costs, the initial expense is balanced by the fact that this system does not consume electricity. Therefore, after installation, the overall use and maintenance will certainly be cheaper than with traditional heating and air conditioning systems.
