FROM THE BLOG | Is all insulation the same?

Is all insulation the same?

We’ve mentioned before how insulation helps to reduce energy costs and keeps your home more comfortable. However, insulation comes in many different types, applications and efficiencies. It can be tempting to think that putting in some insulation will be a magic bullet, but it’s actually more complicated than that. Is all insulation the same?

Today, we’re going to look at the different types of insulation and whether they are all created equal.


There are 5 main types:

1. Batting (Fibreglass, Rockwool, Polyester): Batting comes in sheets and rolls to be cut and placed into roof cavities and under floors. It’s difficult to install in walls, except during construction. It can also release inhalant microfibres that cause respiratory issues. Also compresses fairly easily, reducing its effectiveness. It can be installed DIY, but as we’ve said before, there are complications there.

2. Loose-fill (fibreglass and cellulose): Loose-fill is blown into cavities to create a layer that settles. It’s lightweight, so great for unreinforced ceilings and walls, adding insulation but not too much weight. It’s easier to install in tight spaces, especially cavity walls which are notoriously under-insulated. For example, CosyWall insulation is water repellent and made from glasswool making it extremely useful in our New Zealand climate.

3. Structural insulated panels (polystyrene and polyisocyanurate): Best installed during building, as the panels cannot be squeezed into tight spaces. Offers great insulation, but can work too well, encouraging damp. Panels emit toxic smoke when burned. Polyisocyanurate is a foil-type insulation, which works extremely well, but because it’s a foil barrier, it tends to encourage damp by not allowing any movement of air or moisture at all.

4. Polyurethane spray foam (open-cell and closed-cell): Sprayed into cavities (requiring minimal access) and expands to fit all available space. Great for cavity walls and tight spaces, and can be installed in new builds or already finished houses. Open-cell stops the movement of air and closed-cell stops the movement of both air and moisture.

Each material has different costs, benefits, disadvantages, and R-value. The R-value is the thermal resistance it offers or its efficiency at regulating the temperature.


Basically, everywhere. Here’s how it works: air travels from one extreme to another, until all temperatures are the same. Insulation creates a thermal barrier that helps to slow the movement of air in both directions. So if you want to keep your indoor temperature stable, you need to have a well-insulated home. Warm air can escape through all of your home’s barriers. It’s important to complete the thermal envelope by insulating your ceiling, floor and — most importantly and most forgotten — your walls.


As you can see, all insulation is not created equal. It has different costs, benefits, disadvantages, health and installation concerns, efficiencies and effectiveness. Installed well and properly, insulation can reduce heating costs, prevent the growth of mildew and mould, and keep your home a comfortable and stable temperature and ensuring a healthy home.

If installed incorrectly, it can affect your health, be less effective at thermal control and encourage the growth of damp issues. Insulation also ages, compressing and creating holes in the thermal envelope. It’s important to update your home’s insulation especially if your home is old.

Not sure when your home was last assessed for insulation? Give us a call or email us call on 0800 267 992 or to chat, obligation free, about your home. And if you’d like to find out more about heat loss, energy savings, renovation and insulation, check out our other articles.

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