Underfloor Insulation Options — What You Need to Know

Floor insulation is important no matter where you’re located. Keeping heat in or out is vital to ensure your home stays at the right temperature. Keep reading to find out what you need to know about underfloor insulation options…

Insulating your floors is a very important part of your home. It will keep your house warm during winter and cool during summer. Sustainability Victoria states, “insulating your floors and ceilings will reduce your home’s cooling and heating costs by up to 45%.”

Before looking at what insulation to buy, it’s best to understand how and why the different types work to find the best option for your home.

Photo by Erik Mclean on Unsplash.

The Two Main Types of Floor Insulation

Simply put, bulk insulation is used to keep heat in, while reflective insulation is used to keep heat out. The two can be used in combination for great results and knowing how they work and making sure they’re installed correctly is vital to receive optimal results.

1. Bulk insulation.

Bulk insulation is thick — or bulky — to help keep heat in and is typically made from polyester and glasswool. This type of insulation is thick enough to secure with staples, but still soft and bendable. 

Insulators will generally use bulk insulation to insulate ceilings and walls as it helps prevent heat from transferring through walls, separating the inside from the outside. Polyester and glasswool fibres have air pockets which restrict heat transfer through conduction and convection. There are even more natural bulk insulations you can buy and install yourself, like Knauf’s Earthwool, which is manufactured using recycled glass bottles, but is still soft as ever.

Besides helping with keeping your home from getting too hot or too cool, bulk insulation is also commonly used to help with acoustic insulation for those looking to fine tune their musical and audio space.


2. Reflective floor insulation.

Reflective floor insulation is used to prevent heat produced by radiation from passing into your home. It does this by reflecting the heat back and not allowing it to pass through. This type of insulation is made from foil supported by plastic or thick paper, with a 2–3cm layer of air between the reflective side and the heat source (e.g. roof panels), which allows the heat to escape after it bounces off the sheet. 

It’s important to remember reflective insulation has to be clean for optimal performance. If dust settles on the reflective surface, it won’t be as effective, which is why the reflective side is angled vertically or downwards.


What is an R value?

If you’re looking for underfloor insulation options, you may have seen the term ‘R value’ thrown around and wondered, “What is an R value?

R value refers to the thermal resistance a material possesses. In other words, it measures how resistant a material is to heat flow. This measurement stretches from 1.5 to 7, with higher R values equalling higher insulation — or better heat resistance. This also means there’s less need to spend money on energy, such as air conditioning or heating.

The R value measurement is dependent on insulation type, density and thickness. However, different products with the same R value will have similar insulation effectiveness, no matter what the material, thickness or density is.

Australian R value chart.

It’s important to note that Australia has different R value insulation requirements, based on which climate zone you’re in.

Tips for how to select the best insulation for your floors

  • Installed insulation should result with a snug fit, maximising its ability to prevent heat transfer.
  • If outside noise is an issue for you (e.g. traffic noises), then new or better insulation might be a great solution. Besides preventing heat transfer, heavier insulation also is a great catalyst for bothersome noise.
  • Do the research to ensure you’re choosing the best insulation based on your climate zone, sustainability efforts and if noise is worth considering.

Looking to insulate your floors? You can find insulation contractors or supplies on Localsearch.com.au.

Find the best Insulation Contractors in your area

I'm located in


      Chloe Thistle

      Junior Marketing Administrator

      Chloe Thistle is a Junior Marketing Administrator at Localsearch, bringing her talents and background in digital and social media marketing to her role. She has sharpened her marketing skills across many different industries, including entertainment, fashion and in the B2B field. In her spare time, Chloe can be found either lounging at the beach or five coffees deep at one of her favourite local cafés. No stranger to adventures, she’s trekked to Mt. Everest Base Camp — fueled by coffee of course — has completed the Kokoda Challenge and is always looking for the next mountain to climb! Chloe loves looking for ways to combine her passions for adventure, sustainability and marketing, always chasing the latest trends in both marketing and fashion. Now, she’s utilising her vast life and digital marketing experience to blog and assist in the content with the Localsearch Marketing Team.