Thermal insulation: what is it and how to obtain it

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The ethical imperative of energy efficiency is not to waste energy. A good thermic insulation is a variation of this efficiency, since it has a positive impact on energy saving.

Thermal insulation is essential for the health of your house: it provides comfort assuring a proper temperature and it has a positive impact on energy and cost savings related to domestic heating, avoiding any thermal bridges, the so-called cold spots in the house.

Thermal insulation consists of an insulating surface placed on the outer wall, sometimes also on the inner walls, of the building. If the insulating layer is placed on the outer walls we can talk about a real insulation coating, protecting the house from the external temperature. The insulator can be placed during the house construction. It can be a cavity wall insulation or an interlayer of the wall, or a false wall or a false ceiling. All these solutions avoid heat loss.


How to recognize a thermal insulation material

There are several factors that determine the thermal insulation degree of materials and they must be considered while choosing the most suitable one.

  1. Thermal conductivity: materials that conduct heat very well have a low insulation capability. A material can be considered as insulator if its conductivity is less than 0,14 W/mK (watt per meter-kelvin)
  2. Thermal displacement, meaning the time heat takes to get through the insulator.  In this case this value must be high since it means that the heat takes a long time to get through the wall. A low thermal conductivity corresponds to a higher thermal displacement.
  3. Resistance to steam diffusion, namely the breathability of the insulator material: the lower this value is, the more breathable is the material. This feature improves the insulation, since it prevents condensation, enemy of air insulating property.

Other important aspects are for example the fire-resistance, reducing the propagation in the event of a fire, the durability, namely the resistance to mould, and the toxicity.

These features must be considered in relation to the particular needs of the house, especially the peculiarities of the climate zone, the usable space for insulation and the economic availability.


Different types of insulator material

Insulants can be natural or synthetic. Natural ones stand out for their origin, they can have vegetable/animal or mineral origin. Among the first ones we can name wood or hemp fibrecorkwool and linen. These materials work perfectly as thermal or acoustic insulator, they are breathable and durable, they have a good level of thermal displacement and most importantly they are recyclablebio-degradable and non-toxic. That’s why they are suitable for inner walls, false ceilings and attics. Due to their great performances, they are the most expensive materials and sometimes they are even difficult to lay.

Among the mineral materials we can mention glass woolrock wool, clay and perlite aggregates. Since they are natural these too are renewable and recyclable; furthermore, they are durablefireproof and resistant to mould. They are often used for thermal insulation coating, ventilated covering and underfloor.

Synthetic insulators are chemical materials derived from oil processing, such as EPS (sintered expanded polystyrene), polyurethane foam and polyester fibre. They are excellent external insulators, they are very cheap, easy to lay, waterproof and moisture resistant. To fill the gaps, they are used in foamed forminsulating panels are used on walls and attics, instead.

Which insulator has the best thermal conductivity? The best one is aerogel, a soft material composed of air and silicon, manufactured as sheets, with a 0.014 W/mK conductivity. Then we find autoclaved aerated concrete (0,043 W/mK), a mineral natural material, wood fibre and hemp fibre (0,038/0,043 W/mK) – both organic – and rock or glass wool.


Solar panels: an unexpected help for roof insulation

Properties and origin of different insulators offer a good range of possibilities to find the best solution for our needs, considering also the economic aspect.

If you are oriented towards a green choice, started for example with the installation of PV panels, you have probably found out that natural insulators material, especially the organic ones, are eco-friendlier and they can be installed indoor, in direct contact with people living in the house.

Maybe you don’t know that PV panels themselves work as external thermal insulation for the roof and they help to improve the heat consumption.

According to a study carried out by Jan Kleiss and his team, working at UC Jacobs School of Engineering, the absorbent nature of panels makes them good insulators, preventing sun rays from directly reaching the roof. They thus guarantee a lower temperature (almost 38%) than an exposed roof. Solar panels turn to be useful also in winter time, by releasing during the night the residual heat from the daily activity.

Combining a good PV system with a good insulating system you will reduce the house thermal waste and you will optimize your consumption. You will nonetheless help the environment by decreasing your CO2 emissions.


The first source of sustainable energy is the energy we don’t waste. Energy efficiency, obtained by avoiding waste, should be a primary goal for every activity, domestic or industrial, in order to respect such a valuable asset.

Thermal insulation is a variation of energy efficiency: a good thermal insulation, to which many factors contribute (doors and windows, attics, paints and photovoltaic panels, just to mention some), is a synonym of high efficiency and little waste.

Together with energy generation from renewable sources, thermal insulation makes environments even more sustainable and convenient. Beside managing and optimizing the energy flows, Regalgrid®’s technological platform also communicates with temperature sensors, state-of-art boilers or heat pumps, in order to guarantee the best advantage as from a careful management of electric or thermal energy.