What is the most effective insulation material for a high-performance building envelope?

I suggest Fiberglass: it widely used because it’s affordable, and it has good insulation properties. It’s lightweight and easy to install.

Insulation is a critical component in maintaining energy efficiency and comfort within buildings by minimizing heat transfer. Various types of insulation materials cater to different needs and construction contexts. Here's a brief overview of common types of insulation: -Fiberglass Insulation -Cellulose Insulation -Spray Foam Insulation -Mineral Wool Insulation -Polyisocyanurate (Polyiso) Insulation -Expanded Polystyrene (EPS) Insulation -Extruded Polystyrene (XPS) Insulation -Vacuum Insulation Panels (VIPs) -Radiant Barrier Insulation

It is worthy to add a paragraph about PCM (Phase Changing Materials) and the thermal mass of the local materials (vernacular approaches)

There are also vacuum insulation materials which provides hermal insulation through vacuum. While they are extremely delicate to install and maintain, a very thin layer could be sufficient to provide very high insulation. These are extremely useful in refurbishments and within tights spaces to reduce thermal bridges.

En tant qu'architecte, je considère chaque batiment comme un corps vivant, nécessitant une isolation adaptée à sa structure existante. Le choix de l'isolant doit non seulement viser la performance énergétique mais aussi respecter la nature des murs, qu'ils soient en en pisé, en pierre ou en machefer.

It is important to consider the environmental impact of insulations because they can have one of the biggest overall impacts. Biogenic materials like cellulose and wood fibre have the lowest GHG emissions and can actually store carbon in your building. Using these materials over spray foams and XPS insulations can have a big impact on your overall embodied carbon emissions.

Fire resistance (or better combustibility), in reality, is expressed through a classification according to EN 13501 or other standards. Fire resistance is expressed in minutes but is typically used to classified a wall system or closure such as a door, window, insulated wall or soffits.

L'application d'un isolant inadapté peut affecter la "respiration" du batiment, causant des dommages structurels et des problèmes d'humidité. Par exemple, les murs en pierre nécessitent des isolants perméables à la vapeur d'eau pour permettre une respiration naturelle, alors que des murs en béton peuvent bénéficier d'isolants plus denses.

In my experience, fibrous insulation (Rockwool for instance) or more expensive compared to cellular insulation such as PUR/PIR. Also, fibrous insulation come in different solutions, including moisture resistance ones. An air gap should not be considered only for reflective insulation as ventilation is an important factor especially in ventilated facades.

Coming from Morocco, where the old cities called Medinas do not use conventional insulation materials but still keep people warm in winter and cool in summer, I would like to point out that one inherent disadvantage of high-performance insulation materials is their significant carbon footprint. To reduce the embodied carbon of insulation, several strategies can be employed: -Minimize insulation requirements and optimize building performance using strategies such as passive design, airtight construction, insulation optimization, thermal mass. -Utilize reclaimed or recycled materials that have a lower environmental impact than virgin materials. -Incorporate low-carbon and carbon-storing materials that sequester carbon from the atmosphere.

To follow the adage “we can’t manage what we can’t measure,” the initial step before choosing the insulation material is to clearly define the building’s needs. To achieve this, here are some steps to follow: -Evaluate the external factors influencing the building envelope’s thermal performance, such as local climate, topography, and orientation. -Establish a performance baseline or conduct an energy audit for existing buildings to assess energy needs. -Engage occupants and stakeholders early on to gather their expectations, preferences, and feedbacks.

Thermal inertia is also an important parameter to consider when chosing an insulation product and its position within the external wall build up.

Chaque projet doit être évalué attentivement pour choisir l'isolant le plus approprié, améliorant ainsi l'efficacité énergétique tout en préservant l'intégrité du batiment.

Yes, aerogel is indeed recognized as an exceptional insulation material, especially for high-performance building envelopes. While aerogel insulation has numerous benefits, it's essential to consider factors such as cost, availability, and specific project requirements when choosing insulation materials. Additionally, advancements in aerogel technology continue to address challenges and expand its range of applications in the construction industry.

Il ne faut pas négliger les isolants naturels tels que la paille ou le chanvre dans le choix des matériaux pour l'enveloppe de batiments à haute performance. Ces matériaux, avec leur forte inertie thermique, offrent d'excellentes performances d'isolation tout en réduisant considérablement les émissions de CO2. Ils incarnent le retour à un "bon sens paysan" dans la construction moderne.

The continuity of insulation is a very important factor that can't be neglected. Thermal bridges can reduce the effectiveness of any insulation material significantly and reduce the R-value of the envelope assembly regardless of the insulation material.

It's important to consider the specific requirements of your project, such as local climate conditions, building codes, and sustainability goals. Additionally, the overall effectiveness of the building envelope depends on factors like proper installation, air sealing, and the integration of insulation with other building materials. Consulting with a building professional or insulation specialist can help you make an informed decision based on your specific needs and circumstances.

Le batiment, à l'instar d'un corps humain, doit être traité avec des matériaux qui respectent son intégrité et son environnement. Les isolants naturels, en plus de leurs propriétés thermiques et écologiques, contribuent à la santé globale du batiment, permettant une régulation naturelle de l'humidité et de la température, tout en étant respectueux de l'environnement.L'adoption d'isolants naturels comme la paille ou le chanvre est un choix judicieux, non seulement pour leurs avantages écologiques et thermiques, mais aussi pour leur faible impact carbone. Ils représentent une approche holistique, durable et sensée de la construction et de la rénovation.