A wall can have an excellent datasheet and the house can still be uncomfortable. It happens when a large picture window takes the afternoon sun without shading, or when the air is not exchanged properly. The HES datasheet declares 18 hours of thermal lag at 320 mm of thickness. That is a good figure. It becomes comfort only inside a design that holds together windows, shading, ventilation and internal mass. That work is done by the designer.
We are preparing the first H0ME house with HES technology. This episode is about what comes before the construction site: who designs, who builds, and how to read a technical figure.
What the 18 hours say
Thermal lag is the delay, in hours, with which the temperature peak on the inner side of the wall follows the peak on the outer side. The definition comes from UNI EN ISO 13786. The 18 hours of the HES datasheet, at 320 mm, measure this delay.
They are not the time heat takes to cross the wall. And they must not be confused with the decrement factor, which is another parameter. Knowing how much the peak is delayed does not say how strong it will be.
For this reason, datasheet and design answer different questions. The datasheet describes a performance of the material. The design looks at how that performance works in the building, with the other choices.
A useful question to ask the designer: "I would like a large picture window in the living room. How do we evaluate it together with shading and ventilation?" You start from a concrete desire and bring it inside the design.
Who designs, who builds
According to the manufacturer's declaration of conformity (LVS EN ISO 17050-1), the HES hemp-lime biocomposite has non-load-bearing use. The structure that holds up the building is defined in the design. Choosing the material of the walls does not mean the structure has already been decided.
The design and the calculations are signed by the licensed professional appointed for that house. This applies to every house, including the first H0ME house. H0ME operates as General Contractor and has been licensee for Italy of the HES technology since 2019.
The two roles work together from the start. The choice of the building system goes hand in hand with the design. The HES figure on the wall is a technical starting point. How well you will feel in the rooms is what the designer evaluates on the whole building.
In this episode we talk about roles, not people.
What it means for those who will live in the house
At the first meeting you can bring your habits, in addition to your ideas about the shape of the house. In which rooms will you spend the most time? Where do you want more light? What do you want to ask about air exchange?
You don't need to arrive with solutions already decided. A list of priorities helps you explain what you are looking for and ask how the design will take it into account.
Let's go back to the living room. The large picture window opens a discussion on windows, shading and the rest of the building, and the wall is part of it. You start from the house you want to live in and verify what the wall needs.
The same goes for a datasheet: you can ask which thickness the figure refers to and how it will be used in your design. If humidity interests you, there is the article on the breathing wall.
H0ME builds only new houses, on a plot of land or with a demolition and reconstruction. The first H0ME house with HES technology is in preparation: so far, no HES house of its own has been built. This series tells the road toward that first construction site.
FAQ
Who signs the design of the first H0ME house?
The design and the calculations are signed by a licensed professional appointed for that house. H0ME operates as General Contractor.
Do the 18 hours say how cool the house will be?
They indicate a delay between temperature peaks. Comfort depends on the whole design.
Does hemp-lime support the building?
The HES biocomposite has non-load-bearing use. The structure that holds up the building is defined in the design.
Discover the HES technology. Previous episode: "Breathability: mu, the number nobody looks at". The next episode moves forward toward the first H0ME house.
Article produced with the support of artificial intelligence and reviewed by the H.0.ME. editorial team.