What are the numbers behind WELL?

Before Article

Introduction and the importance of WELL

WELL is a standard dealing with the health score of an office building. As a consultant at CFP, I wasn’t very familiar with the WELL standard, and at first WELL seemed a little obscure. Even so, I was curious. That’s why I approached Berber, our WELL expert at CFP. She explained to me that technically it’s actually quite a challenging standard. I was inquisitive and so I went looking for the numbers behind WELL. The WELL method not only proves to be a practical approach to improving health and productivity, it is also technically challenging. To start with, the numbers as to why healthy buildings are important:

  • On average, the Dutch spend 90% of the day indoors;
  • In the 1980s, the WHO estimated that about 30% of buildings had a poor indoor climate;
  • The costs of a poor indoor climate amount to around € 3,600 per employee per year.


WELL English
The 10 categories of WELL

At WELL, validation of use plays an important role. The auditor visits the building only after its completion to determine whether the building meets the WELL certification credits in daily practice. The auditor is not involved in the design phase. This means that not only technology is looked at, but also policy and implementation in particular. All credits are evidence-based (i.e. they are proven to contribute to better health and their actual performance is actually tested) and are divided into 10 categories.

While it is mainly important in the case of WELL that policies are adhered to, technology plays an important role in achieving the credits. In order to be able to make an inventory and assess the WELL credits, but also to be able to supervise and implement the measures, substantial technical knowledge is required. For a layman, many credits will be hard to understand. To give an example:

  • A01 Fundamental air quality – Part 4: The Radon threshold (radon is a radioactive particle released into the air from building materials)
    • The radon level should be below 0.15 Bq/L [4 pCi/L]. The test must be carried out per 2,300m2 of usable area by a third party, not a stakeholder

Vertikale tuin

Comfortable and energy saving

We put most of our energy into buildings to keep the air quality and temperature right, because these two aspects play a very important role in the comfort of employees. It also benefits the health and productivity of employees. Fortunately, energy savings and health go hand in hand for the most part. Low temperature heating, for example, is not only more comfortable, but also saves energy. Other examples of energy-saving measures that also contribute to comfort are: preventing simultaneous heating and cooling, preventing draughts and using sun blinds in summer.

The numbers

  • A comfortable indoor climate increases productivity by 10-15%.
  • It is estimated that a lack of fresh air contributes to 35% of absenteeism.
  • Proper ventilation of a poorly insulated building can increase labour productivity by 29%.
  • Individual control over temperature (in a range of 4˚C) leads to an increase of about 3% in logical thinking performance and 7% in typing speed.
  • Office users close to a window sleep an average of 46 minutes longer per night than users further away from windows.
  • View and daylight together explain a statistically significant 6.5% in the variation in absenteeism.
  • There is a direct link between increased adrenaline levels that lead to stress at higher background noise levels.
  • A variety of workplace typologies promotes productivity.
  • Just looking at nature appears to lead to a reduction of physical and psychological complaints.
  • On average, buildings contain 2-5 times as much pollution as outdoor air, but this can be as much as 100 times.

Written by: Orin Tijsse Klasen, consultant at CFP Green Buildings

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