What is The Best Insulation Against The Cold?

What is The Best Insulation Against The Cold: Do you know the winning trio of thermal comfort in winter? It includes heating, of course, ventilation, but also above all insulation. Heating is good, keeping the air warm and keeping the cold out is even better.

No more igloo mode: if your house is exposed to this problem, you must choose more efficient insulation. A long quest? Not necessarily.

You just need to identify the right indicators and ask for advice before embarking on a renovation. I am here to help you.

The essential

A high-performance insulation solution in winter has low conductivity and high thermal resistance.

Among natural materials, cork is a very good option for insulating yourself from cold drafts and humidity.
Glass wool is a great classic in insulation: it is effective in all seasons.

Synthetic insulation achieves an unbeatable level of performance but at the cost of a harmful impact on the environment.

What is The Best Insulation Against The Cold

  1. Thermal insulation
  2. Natural insulators
  3. Mineral insulators: what is the most insulating material?
What is The Best Insulation Against The Cold

1. Thermal insulation

How to choose the best insulation to protect your home from cold drafts? To succeed in your work, you must take into account a combination of several factors:

  • The thermal resistance of the material.
  • Its thickness.
  • Its thermal conductivity.
  • Its effectiveness against humidity.

Reminder: what is winter thermal comfort?

Being comfortable at home in winter, and/or in a cold region, means enjoying a feeling of sufficient warmth in the house: between 19 and 20 degrees in the living rooms, a little less in the bedrooms.

Undertaking renovation work allows you to achieve several objectives:

  • Reduce energy and heat losses
  • Remove thermal bridges that let cold air in
  • Avoid cold walls
  • Reduce the humidity level in the house (it should be between 30% and 70% )
  • Save energy.

All this requires an efficient heating system, ventilation solutions, but also windows: double glazing or even triple glazing and well-placed seals… the effects of which would be nothing without good insulation.

Read also: Wood Fiber Insulation Use and Price per m²

Thermal resistance (R)

  • It is one of the performance indicators of insulation materials: the higher the R-value, the stronger the insulating power.
  • This data is expressed in m²K/W (square meter kelvin per watt).
  • To give you an idea, the figure R = 5 m²K/W is considered a high level of performance. To qualify for certain financial aid, you must reach a minimum of 3.7 m²K/W.
  • Also note: to find the most efficient insulation, be sure to compare the thermal resistances at equal thickness. [What is The Best Insulation Against The Cold]

Thermal conductivity (λ)

  • Thermal conductivity, or lambda coefficient, provides information on the ability of an insulating material to conduct heat.
  • It is expressed in W/mK (watt per kelvin meter).
  • The lower the conductivity, the more efficient the product: this means that it limits heat exchange.
  • To optimize the comfort of your home in winter, remember that thermal conductivity tends to increase in humid conditions.

The thickness of the insulation

  • The thickness of a material also affects its performance. Generally speaking, the higher it is, the more insulating the chosen product is.
  • The thickness required to achieve a certain level of performance is calculated as follows: e = desired R x λ x 100. It therefore varies depending on the intrinsic qualities of the materials.
  • A significant thickness of insulation also means a loss of space inside the house: not to be neglected when defining your project.

Read also: How to Insulate a Millhouse?

Resistance to humidity

Nothing is more unpleasant than a damp feeling in your home when the coldest days come. You’ve noticed: that this reduces the temperature you feel!

To maintain an optimal rate in the house, in combination with ventilation, rely on resistant insulation. Some are naturally so, others can be treated to become so. [What is The Best Insulation Against The Cold]


Have you heard of thermal phase shift to compare insulators? Phase shift refers to the time it takes for external heat to pass through an insulator. 

But this data turns out to be less relevant if you are looking to protect yourself against the cold as a priority: it is above all an indicator of summer comfort.

2. Natural insulators

Is environmental impact one of your priorities? Several products correspond to your beliefs: wood wool, cork, or even cellulose wadding. Which one to choose to benefit from maximum comfort in winter?

Cork for its excellent resistance to humidity

Why cork?

  • Because this type of insulation naturally displays good thermal conductivity, between 0.038 and 0.043 W/mK
  • But also because it resists better in humid conditions, without chemical treatment to protect against water or mold (unlike other ecological solutions).
  • Another significant point: it is very effective in terms of sound insulation.
  • You can use it in rolls or panels to insulate walls, floors, or a roof.
  • Its only drawback is its relatively high price.

Read also: Attic insulation with blown glass wool: the right idea?

What about other natural insulators?

  • Cellulose wadding is an interesting alternative (although more expensive): very insulating, with good moisture resistance properties. But it has a tendency to settle, therefore having a shorter lifespan.
  • As for wood fiber, often cited among the best ecological insulation materials, it is more effective in protecting itself from hot air. [What is The Best Insulation Against The Cold]

3. Mineral insulators: what is the most insulating material?

The best-known mineral insulators are glass wool and rock wool. With almost equivalent performance, certain criteria can help you decide between them.

Glass wool, good value for money

Even if it doesn’t matter much, its thermal conductivity is more interesting than that of rock wool (from 0.030 to 0.040 W/mK).

Glass wool is appreciated for its effectiveness against mold and its sound insulation properties.

Versatile, it can be used to insulate a roof, or attic by blowing or walls.

Your budget can also make a difference: glass wool is generally less expensive than other options.

And rock wool?

It is also one of the mineral-insulating materials very often used in the construction and renovation, of walls and roofs. Despite slightly lower qualities than glass wool, rock wool does the job well, in summer and winter.

Read also:

What is the best synthetic insulation?

Is synthetic fantastic? In terms of thermal insulation, products such as polystyrene and polyurethane are the best insulators: their thermal conductivity coefficients are the lowest.

Maximum performance with polyurethane

With its unbeatable thermal conductivity of 0.021 to 0.028 W/mK, this type of insulation is ideal for protecting your home from winter drafts. [What is The Best Insulation Against The Cold]

  • Also, it is not necessary to install a significant thickness to benefit from all its advantages.
  • It is suitable for all surfaces and particularly for confined spaces.
  • On the other hand, its price is generally higher than those of mineral wools.

Finally, it comes from the petrochemical industry: this requires a particularly polluting manufacturing method. In the event of a fire, it releases harmful substances: in terms of ecology and health, it is not the best choice.

Polystyrene, another effective insulator

Its thermal properties are similar to those of glass wool: it’s up to you to choose the one you prefer according to your budget. Note that this synthetic insulation, like polyurethane, is also derived from petroleum (therefore polluting and toxic).

Comparative table of performances of the main insulators

How to choose between mineral, natural, or synthetic materials? Here are some figures: they give you an overview of the properties of the most often-used insulating products.

Insulating materialConductivity (λ) in W/mKThickness necessary to reach R = 5 m².K/W
Glass woolFrom 0.030 to 0.04016cm
RockwoolFrom 0.033 to 0.04216cm
Wood fiberFrom 0.041 to 0.05018cm
Cellulose waddingFrom 0.035 to 0.04120cm
CorkFrom 0.038 to 0.04320cm
PolystyreneFrom 0.029 to 0.03816cm
PolyurethaneFrom 0.021 to 0.02811cm

Beyond the material, the insulation method is also very important for enjoying maximum comfort in the home. There are multiple techniques: [What is The Best Insulation Against The Cold]

  • from the inside
  • from the outside
  • by blowing…

And it is possible to act on different media:

  • Attic insulation
  • of the roof
  • walls
  • soils

A craftsman can help you choose the most effective solutions to protect your home in winter and save energy.

Read also: How to Restore an Old House?

Leave a Comment

error: Content is protected !!