By Cindy Vissering - SBRCURnet
It has been an interesting discussion in the workshop Active House. The Dutch Building Code provides a fair level of ambition in the comfort aspects of the Active House Radar. But that's a calculated level. What is the actual performance?
The government does not check if the calculated levels agree with the actual output. Even in projects where project partners favour monitoring, it is hardly ever executed. For many reasons, but mainly because of budget. Thus, the question remains to what extend the buildings actually meet the stated level of ambition?
Some interesting topics emerge at the International Conference Healthy Buildings, held in Eindhoven from 18 to 20 May. The workshop Active House is guided by Atto Harsta from Aldus Bouwinnovatie and member of the board of Active House Netherlands.
Kurt Emil Eriksen, Secretary General of the International Active House Alliance kicks off with a general introduction of the Active House vision. Fundamental in this vision is the balance of indoor climate, comfort and energy Comfort and Health of residents is key.
Kitty Huijbers from Nieman consulting engineers and partner of Active House Netherlands follows with an explanation of the operation of the Active House radar and specifications. At last two in-depth presentations with some eye-openers were given; they are discussed below.
Effective light comes from above
(Day) light is not only important for seeing what we are doing, it is also important for our biological rhythm. Bluish light makes us active, and a lack of light makes us sleepy. Hester Hellinga from DPA Cauberg Huygen says that is has recently been discovered that besides the known rods and cones in the eye for converting light into image, also receptors are present which measure the amount of light.
The amount of light has an influence on the activity of certain hormones including hormones which keep us awake and active. The special feature is that these receptors are located in the bottom of the eye, and these catch especially the light that comes from above.
In indoor situations the standards for the level of light relate to the illuminated working surface. So there might be sufficient lumen present on the working surface, but we do not stay awake if the space around it is relatively dark.
Another aspect is that older people need more light than young people. This is because the lens discolors as we get older and lets less light through. These aspects require a different way of handling and design light, because these two aspects are not reflected in the calculation of the daylight factor.
Air quality bedroom top priority
From the importance of light we move onto the importance of darkness. Jelle Laferge of Ghent University has studied the experience of residents sleeping in an Active House. He shows that we are used to design homes for use during the day: residential spaces should get adequate natural light and fresh air.
But it appears that about 70% of the time we are indoors is spent in the bedroom. And since we also spend the longest periods of time consecutively in the bedroom, the amount of ventilation there is the most important. Jelle shows some measurements of Active House dwellings.
As the Active House specifications indicate, 95% of the time a good air quality is measured. The air quality in the bedrooms show high levels for the remaining 5%. This is not so for other rooms in the house. Ventilation systems should be adapted to address this problem.
Jelle also advocates bedrooms with lower room temperature. Because in energy-efficient homes all areas have more or less the same temperature which is not lowered during the night, the bedroom is actually too hot for sleeping. Also most of the rooms cannot be made dark enough.
It was good to see that the attendees wholeheartedly agree with each other about various statements. Among other things they agree that it remains necessary to take into account the comfort aspects in the design of energy-efficient homes. Monitoring the actual performance is of great importance because it is suspected that most buildings do not actually meet the Dutch Building Code level.
They also agreed on the importance of many more aspects of the indoor environment that we even don’t know how to measure A call for further research was heard. Also the Active House specifications can be improved with the findings of today’s speakers. And that is what the Active House partners take home with them.
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