A recurring theme in architecture and construction engineering is that of “sick buildings”.


In our eagerness to control all the parameters and internal and external conditions of our constructions, humanity has tended, increasingly, to make hermetic buildings, replete with electrical and electronic installations that give off electromagnetic waves and ions. Especially in offices we often find ourselves with spaces that are too cold and with a highly charged environment.

Here we will address how to alleviate the excess of electromagnetic charge and the lack of humidity in an environment, with the installation of Canadian or Provencal Wells, for the promotion of sustainable architecture.

In the last decades we have seen with perplexity how groups of users and inhabitants develop specific symptoms that remit once they leave the sick building.

In addition to the static electricity charge that, together with the lack of humidity, causes Lipoatrophy, that is, deformities in the adipose tissues, it is possible that its cause is due to other contaminating pathogens present in the environment, although in both cases, the main cause is only one: the lack of ventilation

The lack of ventilation is an endemic evil in our constructions and ways of life. Both the regulations in carpentry that include aerators (which the user usually covers), as well as common sense, indicate the need to ventilate the spaces with a certain assiduity. There are buildings that from their constitution (for example curtain wall facades) are sealed and condemned to artificial ventilation.

There are different ways to mitigate the excess electromagnetic charge and the lack of humidity in an environment, from traditional formulas, such as opening a window; to other newer ones, such as humidifiers. However, if it is a building in which the façade is not practical or, in short, where natural ventilation can’t be guaranteed, we still have another alternative technique that is committed to providing the natural resources of the environment: Canadian Wells, a very attractive formula for lovers of sustainable architecture.

You may know them, as Provencal Wells, according to the latitude and ultimate goal of the system (heating or cooling the air), but it is exactly the same system. The system consists basically in the use of the geothermal inertia of the land to condition the air that we make flow into the interior of the house through buried pipes at a certain depth of the ground.

Bio-climatic solutions

If we take into account that the temperature of the soil at a depth of about 2 meters, is practically constant throughout the year, we can take advantage of this ability to preserve the temperature to preheat or pre-cool the air we want to introduce inside the construction, making it flow through pipes buried in the ground, sucking it and expelling it through ventilation grilles.

In winter, the outside environment is cold, and the air circulating through the buried pipe (air-to-ground heat exchanger) is heated before entering the interior of the building. In this case we would be based on the principle of the Canadian Wells (since its use began precisely in Canada). While, in summer, the outside air is hot and through geothermal inertia we can lower the temperature of the natural ventilation before introducing it to the interior space. In this case they would be called Provencal Wells (use of which was extended by the homonymous French region).

The air is the thermal conductor, the floor the caloric accumulator, the Canadian tube the heat exchanger and our building, the beneficiary of a natural tempered ventilation.

For the most skeptics who doubt the great performance of Canadian wells as substitutes for conventional air conditioning systems, the news is that these systems can also be connected to the artificial air conditioning system in order to preheat the air they use, reducing the thermal jump and, consequently, the energy expenditure. This factor is of vital importance in the most extreme climates, where bioclimatic ventilation is not sufficient to overcome the thermal loads of the building, either in summer or in winter.

As well as for warm climates, in summer, it is a perfect substitute for artificial systems, in winter it can work as a compliment that helps to improve the energy efficiency of conventional systems, in freezing climates it allows to keep these facilities thawed naturally. However, there is a negative point in the efficiency of Canadian wells, which is its application in tropical high altitude areas (where the days are hot and the nights are cold).

The origin of Canadian wells, or Provencal Wells, as we know them today, originally comes from buried stone channels on the side of a hill. Obviously, these channels had a much lower performance than current systems.

The new fervor of sustainable construction, as well as the first regulations announcing its obligatory nature in the near future (year 2020) of nZEB buildings (Nearly Zero Energy Buildings), have put back into vogue environmentally responsible construction systems and with them the wells Provencals and Canadians, protagonists of this article.

With the aim of obtaining lower consumption and greater energy savings in buildings, each of the pillars on which energy efficiency is based should be considered:

  • Minimize energy losses to the maximum.
  • Generate energy efficiently.
  • Use the energy generated efficiently.

There are real solutions that allow large energy savings and notable improvements in energy certification thanks to geothermal systems based on air-to-ground heat exchangers.
Depending on the configuration of the installation and the location, energy savings can be obtained in electric heating of 75% and between 30% and 60% in the case of heating systems based on fossil fuels, such as natural gas.

The initial investment is significantly higher than in the case of conventional heating systems although the return on investment is significantly faster, amortizing over a period of between 5 and 10 years.

  1. These systems require a minimum investment in equipment.
  2. They require very little operating energy. Only that energy used for the operation of the exhaust fan, if necessary.
  3. They require minimum maintenance, limited to cleaning the pipes regularly.
  4. It is a natural system based on the use of a source of inexhaustible resources. It allows us to save the installation of an artificial air conditioning system, thus reducing the economic and environmental cost.
  5. Create a healthy indoor environment for building users. A renewed environment is healthy by itself, but if we also avoid the excess of static electricity, ions and other pathogens contaminating the environment that cause disease, much better.
  6. They are usually used, in climates near the poles, to avoid the freezing of facilities and interiors.


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