Insulation, Thermal Inertia and Phase Shifting: a winning trio

Insulation alone is not enough

Do you believe that insulating your house very well will guarantee you comfort regardless of the season?

And well, this is (partly) WRONG! For your comfort and your purse, you should absolutely avoid the mistakes made by so many people and choose the right materials for your walls.

Good insulation is often accepted as a basic truth:

• Savings in energy and heating and guaranteed comfort.
• Reduction in future CO2 emissions.
• Good EPB when reselling the house (what about its evolution in the future?).
• And, given the climate shift , it is now known that heatwaves will be more common in our regions… hence the need for insulation!

If insulation is needed, the choices offered are often questionable for a house to be comfortable, affordable and environmentally sustainable.

All you’re missing is thermal inertia

Thermal Inertia and Insulation will efficiently and effectively resolve this problem.

This insulation and thermal inertia include:

• The roof
• The walls (outside and inside)
• The floors
• And even the basement.

Let’s start with the insulation materials. If necessary, they do have their limitations. Insulation materials can be based on minerals, petrochemicals or plants.

We have summarised their properties in a very useful table.

• Download here the summary of the various qualities and the limits of these insulations

After the insulation materials, we now consider thermal inertia

You should know that thermal inertia will be the deciding factor that will make your home comfortable and financially much more cost-effective in the long run.

The heavier the materials, the more energy, and so time, they will need to warm up. By contrast, the lighter they are, the quicker they warm up.

Example: On a warm sunny day, the air, which is very light, heats up immediately. The foam pad of your deckchair, which like most insulation material, will be hot in a few minutes. Your pool (water is 1000 x denser than air) will take ten days to warm up...

This is why heavy materials: natural stone, lime-hemp blocks, solid wood logs, concrete floorings or solid brick walls offer very good thermal inertia (or thermal mass) properties.

And the insulating materials in all this?

Simple insulation materials (mineral wool and foamed chemical products, etc.) are very light, and only offer a little “thermal mass or inertia”. So, they will warm up very quickly.

Obviously the thermal inertia of mineral or petrochemical insulation can be raised by increasing the thickness of these materials. But for a light-frame house, for example, how thick does an insulation wool need to be to have the mass of a solid block?

What’s more these insulation materials use a great deal of petrochemicals, are not at all CO2 neutral (far from it in fact: the HFC that foams the PUR and XPS is 1000 times more active as a greenhouse gas than CO2!), they are not recyclable, they are not nearly as sustainable as advertised and they often have to be replaced after a few decades.

Note that bio-based insulating wools are heavier and have better thermal inertia (though not like stones, lime-hemp blocks or logs!) which makes them very good insulation, particularly for under roofs or in wood constructions (so now do you see the thickness of a compacted bale of straw? And now do you understand why we can put earth in it? Yes, Thermal Inertia!).

Are there advantages to good Thermal Inertia? Phase Shifting…

High thermal inertia offers two significant advantages for your house:

• It can store more energy in the walls. And do so at a slower pace. So when it is very hot, it prevents the inside of the house from heating up too quickly.
• When the temperature cools, the stored energy in the wall mass is redistributed naturally, leaving your house comfortable at all times.

What is thermal phase shifting?

Briefly, the heat from the day gets stored in the heavy walls which prevents the house from overheating, the stored heat is then released at night which in turn prevents the house from cooling down when the nights get cold. In fact, you get air conditioning during the day and free natural heating at night (already a component of the “Comfortable and Affordable”).

In our next blog, we’ll explain in detail the 6 compelling advantages for your house, how good insulation AND good thermal inertia will offer greater comfort while being more affordable and sustainable than you can imagine.