personal experience
Weather and thermal comfort living in a standard Portugese house
We love the sunny Portuguese weather and rather mild climate. Especially during the summer months when the rest of Europe is cooking, temperatures rarely exceed 28°C. For the most part they stay around 26°C which is perfectly fine. Additionally, there is almost always a breeze coming from the sea that would prevent temperatures from shooting through the roof. The sea seems to act like a natural air conditioning system that chills in summer and heats in winter, making it (apart from the wind) a mild climate overall. Even in the winter months it is possible to catch some sun at the beach on a regular basis. During the winter months things can get tough because the house we live in does not feature a heating system. Luckily one of our rooms is equipped with a fireplace which we use regularly during the winter months. This way we can live at least in one room where the air temperature is - say close to our range of comfort. We installed a data logger, that measures temperature and humidity and stores the average temperature for every hour. The data logger is installed at arguably the worst point (for winter), under an uninsulated roof. In the room with the fireplace higher temperatures are expected. As the graphic below shows, inside air temperatures go as low as 12°C and stay below 20°C for about 3’760 hours per year, that is equal to 152 days or 5 months. A rather long stretch. Funny enough it mostly feels warmer outside than inside, especially during the day. A good example of the afore mentioned physical factors of influence on our thermal comfort perception.
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Explanation of the chart:
If we store the average air temperature for every hour of the year we recieve about 8'760 data points (given a regular year with 365 days). There are different ways to evaluate and analyse those data. The graph below shows the accumulated hours of the temperature being higher than 35°C, 34°C, 33°C and so on. The steeper the curve the less hours are found around those temperatures. The graph does not show the specific date and daytime when those temperatures occured, it just gives us an idea of how much time overall we can expect the temperature to be within a certain range. How many hours per year the temperature is higher or lower than a specific number. Thus it can be evaluated what areas we should focus on. For example, there are very little hours per year where the outside air temperature stays above 26°C. Only about 500 hours, which is equal to about 20 days per year. On the other hand about 6'000 hours per year the outside air temperature stays below 20°C. Given that information, what do you think is more important, to have a heating or a cooling system installed?
A few conclusions from the graph below:
- Outside air temperature extremes were 35°C in summer and 1°C in winter
- The extremes did not have a significant impact on inside air
temperatures. Most likely because the outside air temperature did not
spend a lot of consecutive hours around those extremes. For a better
understanding we would have to zoom into a couple of those days.
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1) We find about 3'760 hours where the inside air temperature is below
20°C and it drops well below our thermal comfort zone.
2) Inside air temperature is for the most part about 4-5°C higher than
the outside air.
3) In summertime we find about 500 hours a year where
inside air temperatures were lower than outside.
4) only 300 hours a year inside air temperature exeeded the 26°C mark
which is equal to about 12 days.
Current construction standard
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Whenever there is a new construction site in town we tend to keep an eye on the construction progress with special interest on the insulation part. In most cases it is found that the way the buildings are built and insulated has not changed much - if at all over the past 20 years. Even though it is common sense here in Portugal that it gets cold inside residential homes during winter, not all constructors seem to feel the urge to improve their standard. To be fair, there are some who do but those seem to make the exception. This means similar results to the ones shown in the measurement graphic above can be expected if those houses will not feature a heating system. That is why SHB-Houses raises the level of awareness and pays more attention to detail in order to lift the construction and living standard.
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To be fair, the construction standard overall is very good. In most cases the supporting structure is made of reinforced concrete, a solid design. The work quality is mostly very good. That creates a solid base to work from and with. But in most cases, as mentioned already, insulation standard is where it has been in Switzerland during the 1960's or so.
Based on our own experience, in our house there is almost zero chance to prevent mold from growing. It is not the same in every room though. It seems that the ones "sandwiched" are less vulnerable to growing mold (i.e. 1st floor is sandwiched between ground and 2nd floor). In some ot those sandwiched rooms mold does not grow at all. But how many rooms are "sandwiched" in a 2-story building? It also becomes evident that mold tends to grow in places where there are thermal bridges (no insulation equals colder surface temperature) and cannot be ventilated as good as they should be. So, once the damage is done and thermal bridges for example are implemented, it becomes either extremly expensive to solve the problem at its source or it is not possible at all.
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There are also reocurring features in the design that are questionable. Such as walls along the property perimeter, which will block the best Seaview. For those not used to such walls, it can make one feel enclosed. Not to mention that Portugal has a very low crime rate, making it very easy to live in and get around. And usually most crimes are committed in bigger cities anyways, not in rural areas.
