Blown Insulation Vs Batt Insulation – What’s The Difference? 

With a wide range of insulation products available, it’s easy to feel unsure about which option is right for your home. Two of the most common choices in New Zealand homes are traditional batt insulation and blown insulation. In this article, we’ll break down the differences between blown insulation vs batt insulation and why at Insultech we specialise in blown insulation.  

Blown Insulation Vs Batt Insulation 

Understanding insulation batts 

Insulation batts are commonly used in New Zealand homes. They are often referred to as segments or blankets and are typically made from fibreglass or mineral wool-based fibres. Batts are designed to be fitted tightly between the timber framing of a house. However, the quality of the installation is critical. Even small gaps around pipes or wiring can allow heat to escape. 

Batts have traditionally been used as the primary form of insulation in new home construction, as they are quick and easy to install at the framing stage while the linings are still off. Batt insulation is much harder to install as a retrofit solution because the internal wall linings usually need to be removed. One of the downsides of batt insulation is that it typically has lower R-values than other forms of insulation. 

At insultech we believe building a new home is the ideal time to get insulation right from the start. A well-designed insulation system improves comfort, reduces ongoing energy costs, and ensures your home meets modern performance standards. That’s why we use a blown insulation systems for new builds not just for older homes because they deliver more consistent thermal performance across ceilings, walls, and floors than traditional insulation methods. 

The basics of blown insulation 

Blown insulation is a loose-fill material made from glasswool fibres. Blown insulation is installed using a specialised machine and a hose to distribute the material evenly. The main advantage of this method is that it creates a continuous layer that fills every corner without the need for joins or cutting. 

Ceiling insulation 

For insulating the ceiling, blown insulation is installed at a high density, which ensures it does not shrink or slump as the years go by. We use Loft Blown Insulation, which is a premium product that can reach R-values as high as R9.1, far exceeding the performance of standard batts. This high-density coverage is especially important when we look at heat loss through the roof. Heat naturally rises, so an uninsulated roof space can allow over 30 per cent of your heating to escape. 

When you use batts in a ceiling, they sit between the timber joists. This creates a problem called thermal bridging, where the timber itself acts as a path for heat to leak out. Blown insulation solves this by covering the joists entirely, creating a chilly bin effect where the whole ceiling is sealed. To achieve the same thermal results as blown insulation, you would usually need to install at least two layers of batts. Blown insulation works for almost all New Zealand roof types, including traditional timber trusses and more difficult areas like raked or skillion ceilings. Once the ceiling is sorted, we can look at the walls. 

Wall insulation for existing homes 

Insulating the walls of an existing home can be difficult if you use batts, as you would usually have to remove all the internal wall linings. Blown insulation is a much better solution for retrofitting older houses. We use the CosyWall system, which is specifically designed for this purpose. Instead of a major renovation, we drill small holes into the wall, blow the glasswool into the cavity, and then repair the holes so the house stays weathertight and looks original. CosyWall has CodeMark certification, which gives you peace of mind that the product is durable and meets the highest standards of the New Zealand Building Code. 

Making the right choice for your property

Making the right choice for your property depends on the age and style of the house. If you are building a new home with open framing, batts are a practical option. However, for anyone looking to improve an existing property, or get your insulation right from the start blown insulation is a better choice. It offers higher R-values, better coverage without gaps, and causes far less mess during the installation process. We invite you to book a free home assessment with our team to get professional advice and an accurate quote. Taking the time to get your insulation right is a smart investment in a healthy, comfortable home for the long term.