Roof insulation made a huge change to the house temperature
February 27, 2025
“I could immediately tell the difference that roof insulation makes, even on the hottest days. By keeping my
Insulation acts as a barrier to heat flow and is essential for keeping your home warm in winter and cool in summer. A well-insulated home provides year-round comfort, cutting cooling and heating bills, and reducing greenhouse gas emissions.
Most houses can add insulation to the ceilings, walls and floor to make them more comfortable and save on your energy bills.
| Location | National Building Code minimum R-value | Cost-effective (approx) R-value |
|---|---|---|
| Roof / ceiling | 4.1 to 5.1 | 6.0 |
| External wall | 2.8 | 3.0 |
| Suspended floor | 2.0 | 2.5 |
An insulation material’s ability to resist heat flow is measured by its R-value. The higher the R-value, the better the insulation.
Several factors determine the R-value, including the material type, thickness, and density.
Generally, it is good idea to go beyond the minimum recommended levels, however cost and practicality are important considerations. For reference, typical R-values for the Central Coast are shown in the table.
Insulation products come in two main types: bulk and reflective, which are sometimes combined.
All insulation sold in Australia must display the relevant R-value according to AS/NZS 4859 tested to AS1530 to determine their level of combustibility.
There is a wide range of insulation materials commonly available. These include:
Selecting the right insulation material and type for the job is important. Your Home website provides good information on the different types of insulation materials and how to use them.
In considering which insulation material to use, it is worth considering:
Some types of insulation should be installed by a professional, while some you can do yourself.
DIY works best for accessible roof spaces, where:
In all cases:
Certain materials and installation methods must be handled by professionals due to chemical complexities, specialised equipment requirements, and significant safety risks. These include:
If you wish to get a ‘no obligation’ quotation for insulation, use the link provided to find a reputable local installer.
Almost all existing houses can be better insulated, however some jobs are more complex and expensive than other. We suggest that you get an expert opinion from our partner installer who can tell you what is possible and give you a ‘no obligation’ quote.
Spring and Autumn are ideal times to install insulation, as roof spaces are not too hot and installation companies are most available.
Many insulation materials compress over time and become less effective, so it is worth ‘topping up’ ceiling insulation periodically – say every 5-8 years. Also, check that the insulation in the attic has not been moved, creating gaps that allow heat transfer. This often occurs as things are stored or moved within the attic space, or if new cables, lights or air conditioning has been installed in your house.
Note that for safety reasons, minimum manufacturer’s specified clearances must be left around hot objects, such as flues from fires, recessed halogen downlights and their transformers.
Usually it is possible to add to existing layers of insulation, so long as there is adequate space to allow for ventilation and taking care to follow the product specifications, to minimise the risk of condensation or fire.
If covering a layer of batts or rolls, it is a good idea to place the new insulation at 90o to the existing later to minimise air gaps.
This can happen if you are using your heating or cooling for longer or if your electricity or gas tariffs have increased. For example, the weather may be warmer or cooler compared to a previous period or you may be keeping your home at a different temperature, so that you are using more energy. Or you are actually using less energy but paying more for it because of price rises.
Correctly installed insulation should lead to warmer surfaces in winter and therefore less condensation on walls and ceilings. Mould tends to occur where moist air is trapped so great care should be taken to ensure adequate ventilation in roof spaces and using exhaust fans in bathroom/kitchen.
If your house is already damp and prone to a build-up of mould, installing insulation is usually not the solution and it is best to fix damp issues before adding insulation!
Draughts are one of the biggest and cheapest-to-fix sources of energy waste in Australian homes. Gaps around doors, windows, floorboards, skirting boards, exhaust fans and old fireplaces let warm air escape in winter and cool air escape in summer, forcing your heating and cooling systems to work harder than they should.
Sealing these gaps is one of the best ways to cut bills while also making your home more comfortable.
A typical home can lose a significant share of its heating and cooling energy through gaps and cracks alone so that in many homes this is comparable to leaving a window permanently open. Why pay to heat and cool the outdoors? Sensible draught-proofing goes along with insulation, double glazing or a new heating and cooling system to reduce mould.
Most homes have multiple points where air leaks in and out. The main culprits include:
Depending on the source, draught-proofing can involve:
Many of these are simple, low-cost DIY jobs and most hardware stores stock a range of suitable products.
For a comprehensive range of draught-proofing materials and guides on how to install them, visit the ecoMaster Store.
It’s important not to over-seal a home. Some ventilation is necessary for air quality, moisture control and the safe operation of gas appliances. A good draught-proofing assessment will identify which gaps are unwanted draughts and which are needed vents, so you get the comfort and savings without compromising indoor air quality or safety. Further information is available here
Yes, many draught-proofing jobs are straightforward DIY projects. Sealing gaps around doors and windows with good quality products, or using sealant on skirting boards and architraves are all tasks most people can tackle with basic tools. Larger or more complex jobs, such as sealing structural gaps, retrofitting exhaust fan dampers, or treating an unused chimney, are best left to a professional to make sure the work doesn’t create new problems.
A simple way to check is to run your hand slowly around door and window frames, skirting boards, and vents on a windy day to feel for moving air. You can also hold a lit incense stick or a candle near these spots – flickering smoke or flame reveals airflow. For a more thorough assessment, a home energy assessor or draught-proofing professional can carry out a proper inspection, sometimes using a blower door test, to identify every significant leak in the home.
Draught-proofing on its own won’t fix an existing condensation or mould problem, and if it’s done incorrectly it can make things worse by trapping moisture indoors. The key is to seal unwanted draughts while keeping or improving deliberate ventilation, such as exhaust fans and vents in bathrooms, kitchens and laundries, so that moist air still has a way to escape. Done properly, draught-proofing combined with good ventilation habits can actually help reduce condensation by keeping the home’s temperature more stable.
Gas heaters, wood fires and other combustion appliances need a reliable air supply to operate safely and avoid a build-up of carbon monoxide. If your home has these appliances, any draught-proofing work should be carried out carefully, and the appliance’s required ventilation should never be sealed off. This is one of the main reasons it’s worth getting a professional assessment before draught-proofing a home with gas or wood heating, rather than sealing every gap yourself.
Draught-proofing, insulation and double glazing all work together to improve your home’s thermal performance. Sealing gaps stops the constant ex
change of air that undermines the benefits of insulation and double glazing – there’s little point insulating a ceiling or upgrading your windows if warm or cool air is still leaking out around doors and vents. Addressing draughts first means every dollar you later spend on insulation or glazing goes further.
For more information, see the Your Home government site.
“I could immediately tell the difference that roof insulation makes, even on the hottest days. By keeping my
“I can keep my home at a comfortable temperature on most days without resorting to using air conditioning.”