Why are ceiling fans so important in RE2020?

In a previous text, we explained how the RE2020 changes the approach to summer comfort.

Here we explain the role of air speed, and the reasons why ceiling fans are virtually indispensable for achieving summer comfort objectives.

How do ceiling fans improve summer comfort?

Ceiling fans accelerate air movement and therefore promote heat loss through the skin. In RE2020, summer comfort calculations for ceiling fans are based on air speed (without taking humidity into account).

Heating professionals will be familiar with the diagram below, taken from the Woods Ventilation Guide[1].

Figure 1 – Cooling felt as a function of air speed

So the higher the air speed, the higher the temperature the occupant can withstand.

RE2020: ceiling fans become a must

Three research consultancies, Bastide Bondoux, Pouget Consultants and Tribu Energie, have worked together to publish a study in July 2021[2] that highlights the major role of ceiling fans in summer comfort in the RE 2020.

Here are two passages:

• Ceiling fans are a very simple way of drastically reducing discomfort (p.8).
• (In zone H3 – Mediterranean coast), fans will become the benchmark for limiting discomfort in summer. The action of fans on degree hours is still highly valued. Ceiling fans appear to be a very simple way of drastically reducing discomfort, and are even more effective than air handling units in zone H3 (p.41).

It is therefore clear that ceiling fans are one of the essential tools for achieving the regulatory targets.

[1] This table appears here for information only. [2] The members of the consortium that financed the study are as follows: CIM béton, Isolons la terre contre le CO2, Ignes, EDF, Filmm, FF Tuiles et Briques, Uniclima.

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