Insulation is important because it helps to keep warm areas warm and cool areas cool.  This is an important concept to understand regardless of the type of building one builds. Insulation is important in any type of building and is the key to keeping energy costs down.

There are many different types of insulation that include different types of foam, cellulose and fiberglass.

Here are different types of insulation.

If a home is not properly insulated, up to two thirds of its heat energy can be lost.


This diagram show the basic principles of passive solar design, except that insulation needs to be added underneath, to the north wall, and roof.

This diagram show the basic principles of passive solar design, except that insulation needs to be added underneath, to the north wall, and roof.

In regard to passive solar design, insulation is used in the building’s design so that it can work together with thermal mass.   Thermal mass is a dense material that can store and radiate heat.

It is recommended that a passive solar house have insulation on the outside of the thermal mass so that the heat stored within the mass can be utilized to keep the inner temperature warm and stable.  Remember that insulation allows a warm building to stay warm and a cool building to stay cool.



The diagram shows common leaks that allow heat to escape, Courtesy of

A lack of insulation will drastically impact the heating and cooling storage capacities of any building.

The diagram shows common leaks that allow heat to escape in a traditional building.

Heat moves to constantly try to reach equilibrium and will constantly move from warm to colder areas. When a door is opened to a cold winter evening, heat will move out of the house while the cold sweeps in. Similarly, when reaching for the ice cream while the freezer door is open, heat moves into the freezer, as cold air rushes out. In regard to both the building and the freezer, the presence of insulation functions to keep areas warm or cool areas stable. In buildings, it is desired to live within a constant, comfortable temperature, regardless of the temperature outside of the building.



This polystyrene SIP shows the chase for the electricity within the insulation.

There are also building materials that incorporate insulation within its structure.

These types of building materials include Structure Insulated Panels (SIPS), Insulated Concrete Forms (ICF’s). For more on Styrofoam types of insulation, see this post on polystyrene.



The economical solution to a warmer house in the winter and a cooler house in the summer is to insulate it well, while understanding the movement of heat.

A better solution is to build a passive solar house!  Visit the passive solar building photo gallery.



10 Responses

  1. Benjamin says:

    Thanks so much for explaining everything, was looking into educating myself on this so I would be able to better relate with the professionals I’m working with handling all this. Great post and I would have to say it’s best to rely on the insulation professionals to get the job done right. Saves you time.

  2. Cheska J says:

    This is such an informative post and I’m happy that I’m finally better educated on the nitty gritties of insulation. It helps that I’m more informed as when I discuss with an insulation professional, I actually will better understand the context of everything he’s talking about! I’ve always had to rely on insulation professionals to deal with these sort of things!

  3. Arie Kakiailatu says:

    Hi there,
    We are living by the equator –> a tropical environment thus. The temperature is constant thru the year, 33 C during the day and 24 C at night. My question is simple, which one gives a better cooling solution, among insulation (say styrofoam panels) on the outside of external wall, OR, injected foam in between the (double) brick walls OR insulating panel (styrofoam) in the interior of the wall.

    Kindly tell me which one gives the best solution ?

    With regards, Arie Kakiailatu – Jakarta – Indonesia

    • Keya Lea says:

      Hi Arie, as for your question, it really depends on the R-value and the other materials that are used. Because the thickness of injected foam or styrofoam panels can vary, it will also vary the degree of cooling, so it’s difficult to say which would be a better solution. Another variation that impacts cooling is the type of materials used in the build.

  4. Julius B says:

    Thank you for information. But I heard another interesting opinion from my friend who lives in England, he said that wall insulation in his climate, are bad because there a lot of wet and rainy days and he will refuse to do air wall insulation. Does someone knows is it really true?

  5. Rob says:

    That diagram made it a lot easier to see where I could have potential issues. I think the insulation I have now is pretty old and I probably should look into getting it changed. Winters are pretty brutal, so more effective insulation would be a win win!

  6. J Holdsworth says:

    Are there significant benefits to having a concrete wall and floor for thermal mass to get the best out of the winter sun or is a concrete floor sufficient?

    • Keya Lea says:

      Well, it depends. 🙂 It depends on the climate that you’re in – do you need the extra heat to be stored? Are the respective walls and floor insulated? The size of the windows is a factor, along with the orientation of the home.

      It’s not a cookie-cutter answer, as passive solar homes rely on inter-related factors, and each of those factors can make a big difference.

      Many passive solar homes use solar mass in the walls and the floor. A Trombe wall is an example of a wall that is built to radiate heat in the winter, as well as keep the building cool in the summer. Any material with thermal mass can help to achieve this.

      Hope that helped to partially answer your question, but it’s really difficult to give an answer without knowing a specific location and the design of the build.

      Best of luck!

  7. Thank you for sharing. Nice written article and well designed graphics.
    One of the most effective things to do to lower electric bills is using insulation for your home. This will allow your household to stay warm even after switching off the heater for a while, and the other way around when it’s cold. Pictures in this article explains this heat movement very well.

  8. Wendy Cartright says:

    Thank you for sharing this information about insulation. It looks like foam is one of the most efficient forms of insulation. I live in a very old home with poor insulation. I will probably upgrade to foam.

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