Eco-friendly insulation

by | May 11, 2023 | Building tips, Home design, Sustainable homes

Insulation is one of those things most homeowners get excited about, taking an out-of-sight, out-of-mind approach to it. However, it plays a vital role in keeping your home at a comfortable temperature and cutting your energy bills down, so it’s not a decision to be taken lightly. With everyone more concerned about the environment than ever these days, there are now numerous eco-friendly insulation options available. Today’s article is all about eco-friendly insulation materials, looking at the pros and cons of each and helping you choose the best eco-friendly alternative for you.

Why are eco-friendly insulation materials important?

When we say eco-friendly materials, we mean materials that don’t hurt the environment. This means these materials focus on zero waste, ethical practices (no unfair working conditions for workers or animal testing), and are reusable, renewable and recyclable. Eco-friendly insulation options are therefore an environmentally friendly means to cut your heating and cooling costs and increase the energy efficiency of your house.

With changes being made to the National Construction Code, new homes will need to reach a higher level of energy efficiency. Quality insulation can go a long way towards reaching the necessary standard.

Benefits of eco-friendly insulation materials.

Often a cheaper option with lower manufacturing costs

Many eco-friendly insulations use a lot less energy during of manufacturing process. Fibreglass insulation uses 10 times more energy to manufacture than denim, wool, cork or cotton insulation.

Energy Cost Saving

While all insulation will help your home maintain a comfortable temperature and therefore drop your energy costs, there is evidence to show eco-friendly insulation is more effective per square inch than other materials.

Sustainable and safe materials

Traditional insulation materials, like fiberglass insulation, can be difficult, and even dangerous to handle. Along with cutting hands, fibreglass can also cause serious issues to the respiratory system if inhaled. Natural materials don’t contain dangerous gas formaldehyde or create harmful greenhouse gases when being made.

What is R-Value?

R-value is a term used when measuring insulation that indicates how well it prevents heat loss and heat flow, also referred to as thermal resistance. The value measures the thickness of the material and its thermal conductivity. Every material that can be used as insulation will have an R-value. For those who love a formula, here’s the one for R-Value:

R-value = Thickness (m) / thermal conductivity (w/ mK)

In layman’s terms, the higher the r-value the better the heat retention. A general rule of thumb is the cooler the climate the higher the r value you need.

What are the best green home insulation materials available?

So, now we’ve had a look at some of the benefits of eco-friendly insulation material, let’s check out the pros and cons of some of the most popular options on the market.

Fibreglass (Glasswool) insulation

The most popular form of insulation, fibreglass is sold in either sheets or loose fill. While not as eco-friendly as other materials, it’s affordable and is effective at helping your home retain heat.


  • Is one of the most affordable and effective materials.
  • Fire and pest resistant.


  • There are eco-friendly alternatives
  • Dangerous to install, with fibres able to cut skin and also be inhaled
  • As Fiberglass insulation sags over time, it becomes less efficient.

Polyester insulation

Polyester insulation’s biggest advantage is it’s that, unlike fibreglass, it is incredibly water resistant. This makes polyester batts ideal for wetter areas like bathrooms and kitchens.


  • Water-resistant
  • Made from recycled materials
  • Easy to install.


  • Lower R-Value than other materials. The colder your winters get, the more you’ll notice this.
  • Not adequate for all environments

Cellulose insulation

Cellulose insulation is an 80-100% recycled material made from old, shredded, recycled newsprint. Whether you love the written word or not, cellulose insulation has several benefits.


  • Is usually locally made, cutting down on transport costs and emissions.
  • Because of boric acid, cellulose insulation is fire-resistant and insect resistant.
  • Has a negative carbon footprint once produced


  • Can cause eye irritation and respiratory problems in some people.
  • Sometimes has issues with moisture, particularly in damp or humid environments.

Spray Foam Insulation

Spray foam insulation is a popular insulation due to its easy application and relative affordability. The good news is there are now eco-friendly spray foam insulation options on the market.


  • Good for preventing heat transfer to your home.
  • Fire retardant
  • Resistant to pests
  • Versatile and easy to install. Fills up to 100x its size.


  • Can be vulnerable to mould
  • Has a smell that some people find off-putting
  • Can be too airtight

Sheep’s wool insulation

As the name suggests, this takes advantage of the insulating properties of sheep’s wool. All natural, 100% bio-gradable and recyclable, there are plenty of benefits to sheep’s wool and it’s great for cold weather.


  • Fire resistant
  • Safe installation with no masks or protective gear necessary.
  • Can absorb moisture without compromising


  • Costs more than its synthetic counterparts
  • Great for a cold climate but not ideal for hotter places.

Reflective Insulation

Reflective insulation is usually made with aluminium foil or aluminised polyester. It’s commonly used in pitched roofs and in wall cavities. It is designed to reflect up to 95% of radiant heat away from the home, making it ideal for hotter climates.


  • Ideal for warmer climates
  • Doesn’t degrade over time.
  • Unaffected by moisture
  • Light and easy to maneuver when installing


  • Expensive material
  • Not suitable for colder climates
  • Need to be dust free for full efficiency.

Hemp insulation

It seems hemp is one of those materials that can be used for just about anything, including insulation. Hemp boards and batting is an excellent insulation material, due to both their effectiveness and the fact it is naturally renewable and recyclable.


  • Naturally hypoallergenic
  • Easy to handle without risk of injury
  • Can help your home become carbon neutral and even improve air quality.


  • Not readily available and can be difficult to find
  • Because of the above, it can be expensive.

Cork insulation

Cork insulation is one of the best-known insulation products on the market. Being more affordable than other insulation, it also has a negative carbon footprint once produced and is ideal for bulk insulation.


  • Good thermal insulation
  • Provides great sound insulation
  • Great at trapping heat without trapping moisture
  • Naturally fire resistant


  • Cork boards are usually quite thick, which can make them difficult to fit in certain walls.
  • Can be tricky and time-consuming to install. You’ll need some heavy-duty adhesive to keep cork in place.
  • Though water-resistant, poor installation can leave gaps that moisture can get through.

Denim insulation (Cotton insulation)

Don’t worry. We’re not talking about filling your walls with old pairs of jeans. Made from entirely recycled materials, denim insulation is an all-natural solution for your home.


  • Resistant to mould, fungus and pests
  • Offers fantastic thermal insulation for colder climates


  • Can attract moisture which can lead to dampness in your home.
  • Is not the most energy-efficient insulation.

Get free advice on eco-friendly insulation for your new home

Looking to cut your dream home’s energy bill? Need help making decisions during your build or communicating with your builder? Buildi is here to help. As client advocates, we are here to help you save time, energy and money throughout your entire building journey. So, get in touch today to find out how we can help you.

Book your free, impartial consultation today!


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