The Importance of Insulation R Values

R Value Chart

What is Insulation R-Value?

The R-Value is the measurement of how effective a material is at resisting the flow of heat energy. So the material with a high R-Value is a better insulator than material with a lower value which means that a high R-Value material is better at retaining heat. Any material that adds insulation to your home has an R-Value, this includes all types of insulation such as spray foam, fiberglass, or batt insulation along with any doors, windows drywall in finished walls. 

Insulation and airtightness within a home contributes to the home’s building envelope, which is the protective shell that separates a home’s occupants from the outdoor elements. So as the R-Value of doors, walls etc improve so does the strength of the home’s building envelope.

What Does the “R” Stand for in R-Value?

The “R” in R-Value is a measurement that indicates how much heat energy is able to pass through the object in question and it stands for absolute thermal resistance. Any ceilings, wall windows that have a high R-Value will be very useful in the battle to maintain a comfortable interior temperature all year long. A house in many cases can become much more insulated without up-front investment. For example, a house that has fairly well insulated walls would normally be quite effective at keeping its interior a comfortable temperature but if the house has leaky and poorly insulated windows it will almost certainly struggle. 

This thing is due to the significant drop in R-Value that occurs at each leaky window. But if a house was to be properly air sealed and the R-Value of the windows were to be increased, it would be much easier for the house to maintain or to keep a comfortable interior temperature all year long and utility costs would be significantly lower at every payment.

How Insulation Works

In order to understand how insulation works, we first should understand heat flow that involves three basic mechanisms which are conduction, convection and radiation. The first mechanism conduction is the way heat moves through materials. The second one convection is the way heat circulates through gases and liquids. While the third one radiant heat travels in a straight line and heats anything solid in its path that absorbs its energy. Reflective insulation and radiant barriers systems work by reducing radiant heat gain.

Heat flows from warmer to cooler until there is no longer a temperature difference. Which means that in winter heat flows directly from all heated living spaces to adjacent unheated garages, basements, attics and even to the outdoors. But also in your house heat flow can move indirectly through interior walls, ceiling and floors, wherever there is a difference in temperature. Heat flows during the cooling season from the outdoors to the interior of a house.

In the winter to maintain comfort the heat lost must be replaced by your heating system and the heat gained in the summer must be removed by the cooling system. You will decrease this heat flow by properly insulating your house which provides effective resistance to the flow of heat.

R-Values for each Insulation Type

In terms of its thermal resistance R-Value is rated the resistance of an insulating material to conductive heat flow. The higher the R-Value the higher insulation power has the material. R-Value depends on the type of insulation, its thickness and density but also there are some other materials whose R-Value also depends on moisture accumulation,, temperature and aging.

R-Value of Materials and Depths

MaterialR-value/in3 1/2″5 1/4″10″ 12″15″
Fiberglass (batt)3.1 – 3.410.8 – 11.916.3 – 17.831.0 – 34.037.2 – 40.846.5 – 51.0
Fiberglass blown (attic)2.2 – 4.37.7 – 15.011.5 – 22.622.0 – 43.026.4 – 51.633.0 – 64.5
Fiberglass blown (wall)3.7 – 4.312.9 – 15.019.4 – 22.637.0 – 43.044.4 – 51.655.5 – 64.5
Mineral Wool (batt)3.1 – 3.410.8 – 11.916.3 – 17.831.0 – 34.037.2 – 40.846.5 – 51.0
Mineral Wool blown (attic3.1 – 4.010.8 – 14.016.3 – 21.031.0 – 40.037.2 – 48.046.5 – 60.0
Mineral Wool blown (wall)3.1 – 4.010.8 – 14.016.3 – 21.031.0 – 40.037.2 – 48.046.5 – 60.0
Cellulose blown (attic)3.2 – 3.711.2 – 12.916.8 – 15.032.0 – 37.038.4 – 44.448.0 – 55.5
Cellulose blown (wall)3.8 – 3.913.3 – 13.619.9 – 20.838.0 – 39.045.6 – 46.857.0 – 58.5
Polystyrene Board3.8 – 5.013.3 – 17.519.9 – 26.238.0 – 50.045.6 – 60.057.0 – 75.0
Polyurethane Board5.5 – 6.519.2 – 22.728.9 – 34.155.0 – 65.066.0 – 78.082.5 – 97.5
Polyisocyanurate (foil-faced)5.6 – 8.018.2 – 28.029.4 – 42.056.0 – 80.067.2 – 96.084.0 – 120.0
Open Cell Spray Foam 3.5 – 3.612.2 – 12.618.4 – 18.935.0 – 36.042.0 – 43.252.5 – 54.0
Closed Cell Spray Foam6.0 – 6.521.0 – 22.731.5 – 34.160.0 – 65.072.0 – 78.090.0 – 97.5

The insulation that fills building cavities densely enough to reduce airflow can also reduce convective heat loss. Radiant barriers, different from traditional insulation materials, are highly reflective materials that re-emit radiant heat rather than absorbing it. The factors that define the amount of insulation or R-Value are the climate, type of heating and cooling system and also the part of the house you plan to insulate. Air sealing and moisture control are important to home energy efficiency and health.

Best Insulation Material

You will come across a bunch of options when it comes to choosing the right insulation material for your home but we are going to help you choose which one is best for you. The table below shows the quantities of the three most used insulation types or materials:









We Do Spray Foam Insulation

Spray foam is a vapour barrier that protects the foundation of a building and also it creates an air barrier that acts as the first line of defense against not only radon but also other malignant gases. Here at Eco Spray Insulation, we are committed to help our clients understand the how and why of their home renovations so that you feel confident when choosing our services.

If you have any questions about R-Value that we do not touch on here or if you would like to take the first steps towards a more energy efficient home, feel free to give us a call at 1-416-860-6664, or by email at [email protected] and our Professional Team will be happy to assist you.

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