The ability of insulation to reduce home heating and cooling costs continues to remain surprisingly overlooked throughout Australia despite recent focus on the dismal energy efficiency of the country’s built assets.

“The one thing that we’re finding is that people are choosing not to insulate, or they’re not even thinking about insulation when they’re doing new projects,” said Sandra Skelly of underfloor heating systems provider Comfort Heat. “The architects aren’t specifying it and the builders aren’t suggesting it.

“Builders ask us all the time if we should insulate when the assumption should be that they are already.

“It shouldn’t be a choice – yes, you should insulate, you can never insulate enough - the more you insulate, the more the heating and cooling properties of the house will improve.”

Skelly believes a big part of the reluctance to install insulation is due to concerns over upfront expenses, along with a failure to realize the long-term savings that can be achieved via increased efficiency.

“I think insulation is being overlooked largely due to cost considerations,” she said. “It ends up being that added extra, because if you don’t need to have it, then it’s the first thing that is crossed off the list.”

While the recent spate of home renovation shows has left the average consumer far better apprised when it comes construction methods and approaches, insulation still fails to receive as much attention as other building parts.

“Insulation isn’t even one of the things people are considering when it comes to bricks or glass - a lot of people are looking at e-glass and various types of window treatments that keep the heat in, but insulation still isn’t on the list that they’re checking off," Skelly said.

“Simple insulation products, such as an extruded polystyrene underneath their slabs, are still being overlooked.”

According to Skelly, failure to give more thorough consideration to the potential insulation needs of homes translates into greater costs further down the line as well as poor energy performance.

“It concerns me that insulation seems to be an afterthought, because it ends being a costly one when it’s not included in the original quote of how much this house is going to cost you," she said.

“People are always looking at running costs, they’re worried about the cost of heating their homes, but they’re never looking at what they can do in their design phase, when they would save more by taking insulation into consideration.”

A general perception that insulation is a better suited approach to buildings struggling with colder climate conditions could be a significant factor behind reluctance to adopt it in many parts of Australia.

“The only place where people are really giving it greater consideration is down in Tasmania and its more alpine regions, where it does get really cold, as well as the western tablelands of NSW,” said Skelly.

Concerns about thermal lag and the potential impact of insulation on the cooling of homes in Australia’s predominately warmer climate region could be another factor behind the market’s neglect of insulation.

“One thing about Australia is that it may heat up during the day in summer, but it also cools down at night, and what you don’t want is for the house to store the heat,” said Skelly.

Such concerns are misplaced in Skelly’s opinion, as insulation serves to enhance the cooling of indoor environments by preventing the ingress of external heat.

“If you’ve got the insulation products in the house, it won’t heat up as much, so you have even less of a thermal lag,” said Skelly. “The house will operate even more efficiently if it doesn’t absorb the heat in the first place.

“If you insulate, you have to be improving the efficiency of home both heating and cooling - heat moves in from hot to cold, so when you’re trying to heat an insulated house during winter the heat moves from the house to the outside

“The opposite happens if you’re air-conditioning a house during summer – the the heat will move from the outside towards inside, so you still want the insulation to prevent this transfer of heat.”

  • Thanks Marc,

    I would have to disagree with people choosing not to insulate in our area. Insulation is one of the main topics discussed. We are in Southern Victoria so we give both ends of the thermometer a workout.
    I would have to say though, as a builder, finding options to keep a traditional BV home comfortable during temperatures of 35 degrees & above is difficult, & educating the public on the physics of heat transfer is a bit of a challenge. I would like to see more research on products carried out in the area of heat transfer only.

  • I fail to see how anyone could get an occupation certificate or a sign off from a certifier if the building has not been insulated in accordance with Section J of the NCC or individual state energy efficiency standards such as NSW Basix. Insulation is mandatory in all new construction though there may be good cause to insultate over these mandatory minimums, but to state that insulation is "overlooked" is incorrect….. or maybe bulidng certifiers are overlooking it when certifying……but I doubt it.

  • What about designing IN thermal mass? Australian homes are designed and built inside out with thermal mass outside and of course outside the insulated envelope when insulation is used. And when insulation is specified, both the designer and installers ignore the need to join up that insulation to avoid thermal bringing and leaks. Thermal mass inside the insulated envelope IS the thermal shock absorber that moderates temperatures so why do we not use it?

  • Thanks Peter,

    Would you send a little girl down down the street dressed in thick woolen overcoat in 40degC? That is what the bulk insulation industry is telling the public – put in lots of bulk.

    “If you’ve got the insulation products in the house, it won’t heat up as much, so you have even less of a thermal lag,” said Skelly. “The house will operate even more efficiently if it doesn’t absorb the heat in the first place."

    As someone who has been in the insulation manufacturing industry since 1985, I will repeat again, that fibrous bulk insulations in tight roof cavities and walls, as shown in the lead photo, is precisely not desirable in hot climates. This is because the external radiant heat energy is coming into the bulk material and successfully absorbed, and in many cases migrates through the fabric to the ceiling and inner wall linings. In long duration heatwaves, the house is well and truly incubated.

    The thermal test method of bulk insulation is a laboratory test of the material for 4 hours, between two set temperature plates at 33 & 13degC, averaging 23degC for labeling purposes. This is not a real time in-situ test. The regulators continuously ignore this issue, and the public are stranded in ignorance.

    Numerous case stories exist where fibre insulation in ceilings and around airconditioning ductwork force cooling units to underperform, and when foil aluminium shields are fitted between roof rafters and the cooling ductwork itself, cooling appliances work dramatically better.

    In the 2014 National Ratings Framework report (Pitt & Sherry), builders and designers from Townsville said that bulk should not be used in the tropics, and reflective foil used instead.

    More research is definitely needed.

  • Over the last decade I have been using thermal imaging camera for detection of otherwise invisible building defects during my pre purchase residential inspections or new home stage inspections. I have found that one of the most common defects in buildings is poorly laid ceiling insulation. Frequently there are areas in ceilings where insulation is just missing or in ither areas is poorly fitted. Common problems are: not pushing insulation batts all the way to walls or in hard to reach areas or simply not refitting them after installing ducting or lights. In these cases ceiling thermal performance becomes like a leaking bucket, leaking heat out in winter and leaking it in summer. I have numerous examples on my blog on my web site. So even with insulation certificate it means nothing. Nationally we have spent billions on home insulation only to have it poorly fitted when a TI scan of a room takes less than 10 seconds. Figure it out?

  • Thoughtful suggestions , I was fascinated by the insight – Does anyone know where my business could obtain a sample NJ CN 11380-English example to type on ?