Cut Costs: How to Choose the Right Insulation at the Right Price
Get your home winter-ready – and cut heating costs – with the right insulation in your walls, ceiling and floors
Gabrielle Chariton
4 August 2019
Houzz Australia Contributor. Freelance writer and editor. I write about anything and everything but I specialise in housing design, kitchens, bathrooms and sustainable living. I pass the time by painting old furniture white, photographing animals, haunting op-shops and dreaming up renovation projects. See more of my work at www.gabriellechariton.com
Houzz Australia Contributor. Freelance writer and editor. I write about anything... More
Winter is well and truly here, which means that finding ways to stay warm and snug is top of the list for most of us. Along with fluffy socks and mugs of hot chocolate, one of the best ways to amp up the cosy factor at home is to install good-quality insulation in your walls, ceiling and, in some cases, under the floor. Think of insulation as a blanket for your house – it keeps all that lovely toasty warmth inside your home and the winter chill out.
Here’s everything you need to know to choose the right type of insulation for your home.
Here’s everything you need to know to choose the right type of insulation for your home.
While choosing insulation might not be as fun as choosing new furniture or paint colours, it’s one of the most valuable things to get right in your home, says John Lea, principal of Lea Design Studio. “Thermal comfort is one of the most important factors contributing to our quality of life,” he says.
“While we are fortunate in Australia to have a relatively temperate climate, maintaining an ideal temperature of 24 degrees day and night within our homes is still a challenge. Insulation assists with evening out the temperature variations without the need to resort to energy-intensive devices such as air-conditioning,” he says.
“While we are fortunate in Australia to have a relatively temperate climate, maintaining an ideal temperature of 24 degrees day and night within our homes is still a challenge. Insulation assists with evening out the temperature variations without the need to resort to energy-intensive devices such as air-conditioning,” he says.
Benefits of insulation
Not only is a well-insulated home more comfortable to live in, there are economic and environmental benefits too.
“Heat loss during winter and heat gain during summer are controlled with good insulation. This will reduce the load on heaters and air conditioners, which can end up saving on electricity costs,” says David Baillie of David Baillie Architect.
Because insulation prevents warm air from escaping, you won’t have to run the heater as often or as hot, which can significantly reduce your energy bill and your home’s greenhouse gas emissions over the long-term. This saving will be even greater if your home is constructed from materials that have no inherent insulating properties, such as a corrugated iron roof, says Lea.
Baillie says another benefit is that “good insulation will deliver a significant amount of sound reduction and, in some cases, a reduction of drafts in a building”.
Not only is a well-insulated home more comfortable to live in, there are economic and environmental benefits too.
“Heat loss during winter and heat gain during summer are controlled with good insulation. This will reduce the load on heaters and air conditioners, which can end up saving on electricity costs,” says David Baillie of David Baillie Architect.
Because insulation prevents warm air from escaping, you won’t have to run the heater as often or as hot, which can significantly reduce your energy bill and your home’s greenhouse gas emissions over the long-term. This saving will be even greater if your home is constructed from materials that have no inherent insulating properties, such as a corrugated iron roof, says Lea.
Baillie says another benefit is that “good insulation will deliver a significant amount of sound reduction and, in some cases, a reduction of drafts in a building”.
Is it expensive?
If you’re building a new home or renovating, insulation will generally represent less than one percent of your overall construction costs. For retrofits, there are plenty of cost-effective options that will deliver a noticeable impact on your home’s internal temperatures – and you’ll recoup your costs over the long-term via reduced power bills.
“Spend big upfront on insulation and it will save you a lot of money in the long run,” says Sheralee Hogan, owner of Site Specific Designs.
Find a licensed builder near you on Houzz to install insulation in your house
If you’re building a new home or renovating, insulation will generally represent less than one percent of your overall construction costs. For retrofits, there are plenty of cost-effective options that will deliver a noticeable impact on your home’s internal temperatures – and you’ll recoup your costs over the long-term via reduced power bills.
“Spend big upfront on insulation and it will save you a lot of money in the long run,” says Sheralee Hogan, owner of Site Specific Designs.
Find a licensed builder near you on Houzz to install insulation in your house
Where should I install it?
To get the most bang for your buck, install insulation wherever your building is most vulnerable to heat loss in winter and heat gain in summer. “Roofing is generally the most important as it is more directly exposed to the heat of the sun in the day and the cold open skies at night,” says Lea. If your home has a raised floor – exposing it to greater temperature fluctuations than a slab on the ground – you’ll want to consider insulating here too.
Hogan says houses typically lose about 30 percent of their heat through the ceiling or roof, 20 percent through the windows and 20 percent through their walls, with the remaining portion depending on air leakage and insulation in the individual property.
“If possible, pay for better-quality glass in windows and doors,” she says. “But if you can’t, at least look at any areas that can be sealed against draughts, as you can lose about 20 percent of heat through air leakage.”
To get the most bang for your buck, install insulation wherever your building is most vulnerable to heat loss in winter and heat gain in summer. “Roofing is generally the most important as it is more directly exposed to the heat of the sun in the day and the cold open skies at night,” says Lea. If your home has a raised floor – exposing it to greater temperature fluctuations than a slab on the ground – you’ll want to consider insulating here too.
Hogan says houses typically lose about 30 percent of their heat through the ceiling or roof, 20 percent through the windows and 20 percent through their walls, with the remaining portion depending on air leakage and insulation in the individual property.
“If possible, pay for better-quality glass in windows and doors,” she says. “But if you can’t, at least look at any areas that can be sealed against draughts, as you can lose about 20 percent of heat through air leakage.”
What is R-value?
When shopping for insulation, you will come across the term ‘R-value’, which refers to the absolute thermal resistance of an insulation barrier. This is the measure of each product’s ability to resist heat flow. The higher the R-value, the greater the level of insulation.
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When shopping for insulation, you will come across the term ‘R-value’, which refers to the absolute thermal resistance of an insulation barrier. This is the measure of each product’s ability to resist heat flow. The higher the R-value, the greater the level of insulation.
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What are the different types of insulation?
There are two main types of insulation to choose from – reflective and bulk. They work in different ways and are often used in combination to keep homes comfortable in hot and cold seasons. “I use reflective foil under roofing and bulk insulation in the ceiling, as the foil keeps the heat out in summer, but the bulk keeps the heat in during winter,” says Hogan.
Reflective foil: These foils have one or more highly reflective surfaces. They are generally used in the roof to reduce the amount of radiant heat entering the home in summer.
Bulk insulation: This form of insulation comes in batts, rolled blankets, loose fill, spray foam, or structural components such as blockwork or composite insulated wall or roof panels. Bulk insulation uses trapped pockets of air to reduce the heat flow through your walls, floor or ceiling – a bit like wrapping your home in a blanket to keep the warmth in during winter.
There are different insulation styles to choose from within each category. Here’s an overview:
There are two main types of insulation to choose from – reflective and bulk. They work in different ways and are often used in combination to keep homes comfortable in hot and cold seasons. “I use reflective foil under roofing and bulk insulation in the ceiling, as the foil keeps the heat out in summer, but the bulk keeps the heat in during winter,” says Hogan.
Reflective foil: These foils have one or more highly reflective surfaces. They are generally used in the roof to reduce the amount of radiant heat entering the home in summer.
Bulk insulation: This form of insulation comes in batts, rolled blankets, loose fill, spray foam, or structural components such as blockwork or composite insulated wall or roof panels. Bulk insulation uses trapped pockets of air to reduce the heat flow through your walls, floor or ceiling – a bit like wrapping your home in a blanket to keep the warmth in during winter.
There are different insulation styles to choose from within each category. Here’s an overview:
Batts/blankets: Puffy, fibrous batts/blankets are generally made from glasswool (recycled glass and sand), mineral wool (melted rock and slag), sheep’s wool, or polyester (often made from recycled plastic bottles). Batts/blankets are cost-effective and installation is relatively straightforward: the material is simply cut to size and wedged between the structural framework of a house.
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What’s good to know about batts/blankets?
- Some insulation styles offer additional benefits, such as sound insulation or fire resistance.
- Batts/blankets can be installed in accessible ceiling cavities, wall cavities (during construction), and under suspended floors.
- Glasswool and mineral wool can produce harmful and irritating dust particles during installation (wear gloves and a dust mask). This is not an issue with wool and polyester batts.
- Mineral-wool batts are generally firmer than other types, and offer good acoustic properties.
- If glasswool insulation gets wet (such as after a storm), it will need to be replaced.
- Wool insulation generally has a slightly higher R-value than other batts of similar thicknesses.
- Wool and polyester batts will retain their ‘loft’ and therefore R-value over a longer period of time than glass or mineral wool batts.
- Wool is more expensive than other batt types.
Loose-fill insulation
Loose fill comprises small particles of insulating material that are blown into roof or wall cavities via a flexible hose. The benefits of a loose-fill product is that it fills all nooks and crannies, providing a completely gap-free insulating layer and eliminating cold spots.
Loose-fill insulation can cover spots that batts miss, for example around pipes and structural framework.
It’s important to note that some loose-fill insulation used in houses built or renovated before 1990 contained asbestos – a potentially fatal building material.
Today’s loose-fill insulation is most commonly made from cellulose fibre, mineral wool or glasswool. Cellulose fibre insulation is made from recycled newspaper pulp, which is mixed with borax and boric acid for vermin resistance.
Tip: Not sure if your insulation complies with the recommended safe distances from electrical wiring? Find a licensed electrician near you to check if your insulation has been correctly installed.
Loose fill comprises small particles of insulating material that are blown into roof or wall cavities via a flexible hose. The benefits of a loose-fill product is that it fills all nooks and crannies, providing a completely gap-free insulating layer and eliminating cold spots.
Loose-fill insulation can cover spots that batts miss, for example around pipes and structural framework.
It’s important to note that some loose-fill insulation used in houses built or renovated before 1990 contained asbestos – a potentially fatal building material.
Today’s loose-fill insulation is most commonly made from cellulose fibre, mineral wool or glasswool. Cellulose fibre insulation is made from recycled newspaper pulp, which is mixed with borax and boric acid for vermin resistance.
Tip: Not sure if your insulation complies with the recommended safe distances from electrical wiring? Find a licensed electrician near you to check if your insulation has been correctly installed.
What’s good to know about loose fill?
- It’s a great choice for homes with inaccessible or restricted ceiling cavities (such as skillion roofs or cathedral ceilings).
- It can be used to insulate existing cavity walls without removing plasterboard.
- It delivers total coverage for higher insulating performance.
- It must be installed by a professional.
- Some cellulose products may settle over time and the resulting loss of air pockets will impact performance, so ask your installer if this is a possibility.
- You may need to install barriers around light fittings and wiring in the ceiling to prevent risk of overheating.
Foam insulation
Polyurethane foam insulation is available as rigid boards, which are installed in the same way as batts, or the material can be applied with a spray gun. Spray foam can be used inside walls, under roofs and beneath floors. It expands as it dries and forms a durable and flexible coating with a very high R-value.
There are two varieties of spray foam: closed-cell or open-cell, and each type has slightly different properties.
Closed-cell foam: This has smaller bubbles, is more rigid when dry, and has a higher R-value than open-cell foam. It’s also more water-resistant than open-cell, which makes it a better choice for sub-floor applications.
Open-cell foam: This is a good choice for in-wall applications as it doesn’t expand much and it offers better sound insulation than closed-cell foam.
Polyurethane foam insulation is available as rigid boards, which are installed in the same way as batts, or the material can be applied with a spray gun. Spray foam can be used inside walls, under roofs and beneath floors. It expands as it dries and forms a durable and flexible coating with a very high R-value.
There are two varieties of spray foam: closed-cell or open-cell, and each type has slightly different properties.
Closed-cell foam: This has smaller bubbles, is more rigid when dry, and has a higher R-value than open-cell foam. It’s also more water-resistant than open-cell, which makes it a better choice for sub-floor applications.
Open-cell foam: This is a good choice for in-wall applications as it doesn’t expand much and it offers better sound insulation than closed-cell foam.
What’s good to know about foam insulation?
- Spray foam insulation is durable, high-performing, moisture-resistant and has excellent acoustic properties.
- Spray foam can seal over all nooks, crannies and gaps, making it one of the most effective home-insulating products available and an excellent choice for homes in cold climates.
- It produces less dust than fibrous insulation types.
- Its effectiveness relies on correct installation, so be sure to hire a reputable professional.
- Foam can be expensive to install, but its effectiveness will reap ongoing energy savings and help offset the cost.
- Spray foam is a long-term choice: once applied, it’s difficult to remove.
Insulating structural components
If you’re building or renovating, structural components with built-in insulating properties could be a smart option. These dual-purpose products can considerably speed up construction and deliver superior levels of energy efficiency and thermal comfort.
Products in this category include:
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If you’re building or renovating, structural components with built-in insulating properties could be a smart option. These dual-purpose products can considerably speed up construction and deliver superior levels of energy efficiency and thermal comfort.
Products in this category include:
- Structural Insulating Panels (SIPs): SIPs are strong, prefabricated modular panels made from a thick foam ‘core’ that is sandwiched between two rigid sheets of material. They can be used to build walls, floors and roofs and are self-supporting, so no additional framework is required.
- Insulated concrete forms (ICFs): These are rigid foam panels with a hollow core that interlock together. Concrete is then poured into the hollow core. The result? The structural integrity and durability of concrete and the thermal performance of foam formwork.
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Aerated autoclaved concrete (AAC): This is a light, workable concrete filled with hundreds of tiny bubbles that act as insulation. AAC is available as blocks that are used in a similar way to bricks. It is also manufactured into steel-reinforced panels for use in floors, roofs, and interior and exterior walls.
Hempcrete: This insulation material is a highly sustainable walling product made from a mixture of shredded hemp stems, water and lime. Hempcrete is non-toxic, doesn’t off-gas, and provides excellent thermal and acoustic insulation. It’s so effective that building-design firm Connected Design used hempcrete in the walls and roof of this renovation in Sydney’s inner west, to help shield the home from aircraft noise.
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Hempcrete: This insulation material is a highly sustainable walling product made from a mixture of shredded hemp stems, water and lime. Hempcrete is non-toxic, doesn’t off-gas, and provides excellent thermal and acoustic insulation. It’s so effective that building-design firm Connected Design used hempcrete in the walls and roof of this renovation in Sydney’s inner west, to help shield the home from aircraft noise.
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Hi Richard
we need more building police ;-), getting new home builders/buyers to realise the value of passive design, quality checks, blower door tests etc.. is like pushing water uphill with a rake. I was in a house late last year before electrical fitoff and tested the "sealing" by having a candle being blown out by the draft through a cut out - this was laughed off by the builder as "at least they'll have lots of fresh air"
cheers
Brenton
I wish the government would hurry up and introduce better mandatory standards for homes in Australia. Thoroughly well insulated homes (Roof,wall and floors), a well sealed envelope and double or triple glazed windows should be in all new homes. Everyone deserves the right to live in a comfortable home that doesn’t cost a fortune to keep at a comfortable temperature.
It’s ludicrous that Australia has more people die of hyperthermia in their home than Sweden which has much colder outdoor temperatures.
The sooner these things become mandatory the sooner the prices come down and builders will be operating on a level playing field.
Equally important is the need to have adequate testing throughout the build and suitable penalties to apply for not meeting the core standards to protect both the companies doing the right thing and all consumers.
We all need to be pushing governments and those in the building industry to get better outcomes in this very important area.
There needs to be less tax and/or markup on insulation and double glazed windows and other sustainable and eco-friendly products. We are building new and because we want these things our small build will cost more than building a much larger project home.