Buying guide: Home insulation:-
taken from www.choice.com.au
Contents:-
1. Introduction
2. Early birds beware
3. After 1st July
4. How can you tell if an installer is professional
5. Questions to ask before 1st July
6. How insulation works
7. Materials
......- Bulk
......- Reflective
......- Composite
8. Which is best
9. Insulation Products
......- Glasswool and rockwool batts and blankets
......- Natural Wool
......- Cellulose fibre
......- Boards
......- Polyester
......- Reflective foils
10. Table 1: Where to use different insulation products
11. Before you insulate
12. Tips for an energy efficient home
13. Don't get ripped off
......- Loose fill - settling
......- A job poorly done
......- DIY
14. Mandatory energy ratings
15. R-value - what is it?
......- How are they measured
......- Overstated claims
......- System vs product R-values
......- Table 2: Insulation thikness for some specific R-values
......- Table 3: Climate and R-values
Introduction:
Up to 40% of Australian homes – 2.7 million properties – qualify for a saving of about $200 a year in electricity bills, thanks to the federal government’s Energy Efficient Homes Package. Owner-occupiers who have limited or no ceiling insulation will be eligible for a rebate up to $1600 for installing either insulation or a solar hot water system, while landlords can claim a rebate of up to $1000 for insulating their rental property. Additionally, an owner-occupier may be entitled to the $1600 for their own home and $1000 for each investment property owned, if the applicant and properties meet the criteria outlined in the Homeowner Insulation Program guidelines.
As the package is designed to create jobs for the troubled building industry, you cannot install the insulation or solar hot water system yourself. From 1 July till December 2011, the government will provide a list of accredited installers, but if you decide to have insulation installed before then, you can claim the rebate by following the early installation guidelines on the above website. So how can you protect yourself against shonky installers if you want your insulation installed before 1 July? Do you have any recourse if the product is defective and you only find out months later?
The rebate is certainly a boon amidst the economic gloom, but are there any pitfalls? Here's how you can make the most of the scheme.
Early birds beware:
Among other requirements outlined in the early installation guidelines, to claim reimbursement you must obtain at least two estimates or quotes from installers who are either employed by or own registered thermal insulation businesses, and fill out the reimbursement form. The subsidy is expected to cover insulation costs ranging between $1200 and $1600 for an average three-room home; any additional costs will be borne by homeowners.
After 1st July:
From 1 July, if you want to claim the rebate, you’ll need to contact the Department of the Environment, Water, Heritage and the Arts’ website or national hotline on 1800 808 571, leave your details and wait for the department to arrange for an installer. CHOICE has discovered there is no waiting list where you can lodge your name before the program kicks off. Details of how many installers are available to consumers, the response time from your first phone call and when your insulation will be installed are also still unclear. You cannot select your own installer. However, you will be assigned an installer from the government’s list of accredited installers who meet trade and business competencies. This means you won’t have the hassle of getting quotes and being reimbursed.
If any installer on the government’s register fails to meet the required standards, their work will be carefully scrutinised. This may involve make-good arrangements and/or removal from the register if recurring quality issues are detected. Homes will also be selected for random inspection by government-appointed assessors. Households selected for inspection will not be liable for any inspection costs.
How can you tell an installer is professional:
When shopping around for quotes, check that the insulation installer is trained and certified to install thermal insulation to Australian Standard AS 3999-1992. For technical compliance, installers also need to complete and sign the consumer’s reimbursement form.
Installers must also agree that their work may be quality-checked and they will repair any deficiencies found by government-appointed assessors. This compulsory declaration puts the consumer in a good position should they need to pursue a complaint. To ensure quality, some of the installations that occur prior to 1 July will be selected for detailed site inspections.
Several avenues are open for consumers who encounter shoddy installers or defective products. The first step is to contact the installer. If they can’t satisfactorily address your concerns you should seek help at the fair trading department in your state. Consumers are encouraged to bring any quality issues to our attention via the national hotline, as the government is developing a register of installers that will be used from 1 July and it will be useful to have reports of any disreputable operators to feed into that process.
Questions to ask before 1st July:
- Is the installer trained and certified to carry out insulation installation works under Australia Standard AS 3999-1992?
- Does the installer have public liability insurance?
- How many years of industry experience do they have?
- Are they backed by a reputable insulation company?
- Does the product comply with Australian Standard AS/NZS 4859.1:2002?
- Is the R-value correct for your climate zone?
- Does the installed product match that specified in the quote?
- Does the area for which you’re being charged match the size of your roof/ area that is insulated?
- Are there gaps where the batts are installed?
- Are loose-fill insulation barriers provided around downlights (which can overheat)?
- Does the product come with a warranty? How long does the warranty last?
How insulation works:
Heat always travels towards cooler areas. Insulation works by reducing the amount of heat entering from outside your home when it’s hot, and trapping warmth inside when it’s cold outside. The highest percentage of heat transfer occurs via the roof and ceiling, so it’s most important to insulate here. Insulation materials work by affecting some or all of the below three ways of heat transfer.
- Conduction is the direct transfer of heat through solid materials. A metal poker put into a fire is heated through conduction.
- Convection involves the transport of heat via the movement of gases or liquids. You’ll feel convection taking place in a two-storey house — the heat rises from the lower floor to the top.
- Radiation is the transfer of heat across space from a warm body to a cold one — an example is the heat emitted by a bar radiator.
Materials:
Insulation can be grouped into three categories:
Bulk:
Bulk insulation contains fibres that trap tiny pockets of air, which resist heat flow because these air pockets are poor conductors.
Types of bulk insulation available include:
- Glasswool. (fibreglass)
- Rockwool*
- Natural wool* (often mixed with polyester)
- Polyester*
- Polystyrene boards
- Loose fill (made of shredded or granulated material)
Some examples are:
- Cellulose fibre (made from recycled paper)
- Natural wool
- Granulated rockwool
* All come as batts or blankets.
Reflective:
Reflective insulation dramatically reduces infrared radiant heat transfer from a hot surface to a cooler one. It's available as:
- Foil sheets laminated onto paper
- Concertina-style foil
- as a multi-cell foil product (silver batts) — a structure made of two to four layers of foil with air spaces in between
To reflect heat, foil insulation needs to face an air space of at least 25 mm.
Composite:
Composite materials combine elements of the two other types.
These include:
- Batts or blankets with foil backing (foil side facing out)
- Foil-faced boards
Which is best?
While manufacturers of each type tend to talk up their product, experts say any insulation is preferable to none, and every material has its place. The product chosen usually depends on personal issues, such as:
- Price
- Whether it’s made from recycled material
- Where the insulation is being installed
- Who’s doing the installation (DIY or professional installers)
Insulation products:
Glasswool and rockwool batts and blankets:
Glasswool is made largely from recycled glass. The Insulation Council of Australia and New Zealand (ICANZ) says its glasswool is 80% recycled waste glass, and its rockwool about 30-40% recycled building and slag waste.
Batts are inexpensive, easy to cut and fire-resistant. You can install them yourself, but make sure they don’t get compressed or wet, as this will reduce their R-value (thermal resistance).
You also need to check they’re butted together firmly when installed, as gaps will dramatically lower their effectiveness.
Rockwool is denser than glasswool and a better sound absorber, so this may be a good choice if you’re looking to reduce noise. However, it’s generally more expensive than glasswool.
No evidence for health scare
The International Agency for Research on Cancer (IARC) has now confirmed there is no evidence to support previous concerns that these products were possibly carcinogenic in a similar way to asbestos: minute particles becoming lodged in the lungs.
Manufacturers also now produce glasswool and rockwool that are more bio-soluble than before, meaning that if you do happen to inhale some fibres, they leave the body more quickly. You’ll still need to wear protective clothing to install these products though, to avoid skin and respiratory irritation.
Natural wool:
Natural wool is sold as batts, blankets or loose fill. Experts say wool is a niche product in Australia although it’s more popular overseas. Batts are usually wool blended with polyester, which helps them keep their shape. It’s recommended you choose batts that are 70% wool as these are more likely to be fireproof.
In CHOICE tests in 1997, some wool batts failed fire-resistance tests, so ask for assurance that it’s been adequately tested, preferably to the more stringent British Standard 5803 part 4. Also check the insulation has been treated to permanently resist insects that can breed in unprotected wool insulation.
Wool is usually more expensive than other insulation. If used as a loose fill it must be thoroughly scoured and treated with insect repellent and fire retardant.
Cellulose fibre:
Cellulose fibre is made from pulverised recycled paper, and is a loose fill that must be installed professionally. It’s the cheapest bulk insulation to buy and install, but can only be used in roof and ceiling spaces. It’s a good option if your roof space is difficult to access.
Cellulose fibre can be dusty, so you need to put in barriers to prevent it falling down through exhaust fans, vents and the like. Some manufacturers spray it in with a sealer. Cellulose fibre is treated with borax and boric acid to make it fire and insect-proof.
The other issue with cellulose fibre is settling. According to the Australian standard, the R-value any insulation product claims should be the one it achieves in the long term, so a reputable installer will quote the R-value of the product when it has settled.
Boards (extruded polystyrene or expanded polystyrene):
Extruded polystyrene keeps the air in and water out, while expanded polystyrene isn’t water-resistant. Boards are useful especially if space is limited. They have to be installed between non-combustible surfaces, such as plasterboard, reflective foil or brickwork.
Polyester:
Polyester fibres (including recycled PET bottles, such as soft-drink bottles) can also be made into batts and blankets. Polyester is a good choice if you’re insulating a space you’ll go into occasionally, such as an attic, as it doesn’t create extra dust or have loose fibres. It also doesn’t cause any irritation during installation.
Reflective foils:
Foil can cut out 95% of radiant heat, so it’s a particularly good material for keeping a house cool in summer or in a climate that’s hot much of the year. Reflective foil can be installed under the floor, in the roof construction or the walls of a house.
It’s possible to install silver batts yourself, but keep in mind there needs to be a still air space of at least 25 mm below the foil in order for it to be effective. Foil sarking also provides a condensation barrier and can act as a ‘second skin’ under tiles, protecting ceilings and walls from leaks and cracks.
Make sure there are no tears in foils — they decrease its performance as a vapour barrier. Surface dust can also decrease the foil’s R-value, which is why it must always be installed with the reflective surface facing downwards. See Table 1 for where the different insulation products would typically be used.
Table 1: Where to use different insulation products:
| |
Suggested applications for insulation products |
| Insulating material |
Flat ceilings /
pitched roofs |
Cathedral or
raked ceilings |
Timber
floors |
Suspended
concrete slabs |
Concrete
slab edges |
Full
masonry walls |
Framed walls |
| Glasswool batts or blankets |
• |
• |
• |
|
|
|
• |
| Rockwool batts or blankets |
• |
• |
• |
|
|
|
• |
| Glasswool / rockwool — foil attached |
• |
• |
|
|
|
|
|
| Natural wool batts or blankets |
• |
• |
• |
|
|
|
• |
| Polyester batts or blankets |
• |
• |
• |
|
|
|
• |
| Cellulose fibre |
• |
• |
|
|
|
|
|
| Granulated rockwool |
• |
• |
|
|
|
• |
• |
| Natural wool — loose fill |
• |
• |
|
|
|
|
|
| Reflective foil |
• |
• |
• |
|
|
|
• |
| Concertina foil batts |
|
|
• |
|
|
|
• |
| Multi-cell foil batts |
|
• |
• |
|
|
|
• |
| Extruded polystyrene (styrofoam) |
|
• |
• |
• |
• |
• |
• |
| Expanded polystyrene (EPS) |
|
• |
• |
• |
• |
• |
• |
| Expanded polystyrene — foil attached |
|
• |
|
|
|
|
• |
| |
Source: Reproduced with kind permission from Sustainability Victoria’s ‘Energy Smart Housing Manual’.
Before you insulate:
Judging from some subscribers' reports about installation, expect anything from a fantastic to a horrendous experience.
Here’s what to look for before you leap:
- Be clear about what you’re trying to achieve. For example, the major cause of a hot home could be unshaded windows, so installing shading will be just as important as insulation.
- Consider where you’re going to insulate — in existing homes, it’s usually the ceiling, but you can insulate under suspended timber floors.
- Although some experts recommend wall insulation for existing homes, it’s difficult and relatively expensive and usually only occurs during construction or a major renovation. If you’re thinking of building, see Mandatory energy ratings for regulations governing the energy efficiency of new buildings.
- Next, decide which insulation you’re going to use. If you decide on loose fill, you’ll need to have the insulation professionally done; if you want to do it yourself you’ll have to choose batts.
- Check what R-value is recommended for the area you live in, and that you can get that value in the material you’re thinking of using. Ask about the price per square metre of the insulation you’ve chosen — this can vary, so be prepared to shop around.
- Check your chosen product is accredited to the Australian and New Zealand Standard 4859.1. Ask the supplier to show you any test certificates or performance guarantees they have for the product, as well as the product’s fire and pest resistance. (The body that tests insulation is called BRANZ — Building Research Australia and New Zealand.)
- Ensure water can’t get into the roof you’re insulating, as moisture damages some insulation materials’ performance. If it does get very wet, experts recommend you remove it and have new insulation put in.
- One reader told us her laundry ceiling fell in due to the weight of water from a pipe leaking into the insulation. While uncommon, it does happen with some materials, so check your roof space occasionally for leaks, especially after a storm.
- Have an electrician check your wiring to make sure it can be safely covered by insulation, or advise how to work around it.
- Some parts of the building structure (such as ceiling joists or steel frames) may have a lower R-value than the material placed between them, so higher levels of insulation need to be added around those areas. Insulation strips can be inserted between the joist or frame and the roof lining to reduce thermal loss.
Tips for an energy-efficient home:
- Draughtproof Make sure doors and windows are properly sealed — you can buy draught excluders or window seals very cheaply.
- Seal your chimney with a damper. Avoid installing downlights — besides using a lot of energy, they penetrate the ceiling and insulation, causing heat loss.
- Shade Keep your home cool in hot weather by shading the windows that directly receive sun (north, east and west-facing windows). External awnings block more heat than internal blinds (because the heat’s already inside by then). You can also plant deciduous trees near the windows.
- Ventilate Ceiling fans are much cheaper than air conditioning and have less impact environmentally, though they don’t cool the air, only move it about to produce a breeze.
- If you have air con, try to use it only on really hot or humid days and have it zoned, so you can turn it off in the areas of the house you’re not using.
If you live in a dry area of the country evaporative coolers are effective (although unsuitable during water shortages).
Don't get ripped off:
With all insulation, there should be no gaps except around hot objects such as downlighting and gas flues. Experts advise you to get into the roof yourself after your insulation has been installed and check the job has been done properly. The exception is when you've had loose fill installed that's higher than the ceiling joists.
Loose fill - settling
Loose fill can settle over time, so you need to ensure you get what you pay for.
- Talk to your installer - if they claim it won't settle, ask for a written guarantee.
- If they admit to a certain amount of settling you can ask for the installation of more material to compensate. For instance, if the R-value is achieved at a depth of 100 mm, they may install 110 mm. However, this may mean the material will cover the ceiling joists (the usual joist height is 100 mm) until it settles. This could make walking around the roof dangerous.
- The other option is to ask for a top-up in, say, six to 12 months' time.
A job poorly done?
- If you find that an insulation job has been poorly or incompletely done, you're not obliged to pay until problems have been rectified.
- Go to your state's department of fair trading or building regulatory bodies if you're unhappy with the work done.
DIY
The most commonly self-installed materials are batts. You'll find installation instructions on the packaging or the manufacturer's literature.
When installing rockwool or glasswool batts these materials can cause itching and respiratory irritation, so you must wear:
- Dustmask
- Goggles
- Gloves
- Long-sleeved shirt
- Closed shoes
In fact you should really wear protective clothing when installing any insulation to avoid respiratory irritation from dust in the roof space.
Mandatory energy ratings
From July 2006 the Australian Building Codes Board (ABCB), which oversees the building of new homes, updated its energy efficiency provisions. These require new buildings to have a minimum five-star energy rating, which means a new building must reach certain standards for environmental performance. The provisions have been accepted by the Australian Capital Territory, South Australia, Victoria and Western Australia.
This mandatory rating will be part of the Building Code of Australia (BCA) from 2006. The ABCB has divided Australia into eight different climate zones, and the level of insulation and other energy requirements will depend on which one your home is built in.
While the ABCB is made up of representatives for all states, some states may decide to use their own provisions. For example, Victoria has its own five-star requirements, and NSW has a system called BASIX (the Building Sustainability Index), an online assessment tool for checking the energy efficiency of new homes.
Houses undergoing major renovations may also be required to follow these regulations — check with your state’s energy department.
R-value - what is it?:
The R-value of a material describes its thermal resistance — how much the material inhibits the transfer of heat. The higher the R-value, the more effective the level of insulation.
With bulk materials, the thickness of the product is the key factor in determining its R-value (see Table 2).
The R-value you’ll need depends on your particular climate. See Table 3: Climate and R-values or ask your local council what the appropriate R-value for your area is.
How are they measured?
R-values can be measured depending on the direction of heat flow (upward or downward). They’re known as ‘up R-values’ (resistance to upward heat flow, also called winter R-values) and ‘down R-values’ (resistance to downward heat flow, also known as summer R-values).
Foil-insulated systems tend to have higher down R-values. In hot, humid climates where houses are naturally ventilated, high down values and lower up values are appropriate for roofs and ceilings.
Overstated claims
Since May 2005, the Building Code of Australia has required all insulation materials to comply with the Australian and New Zealand Standard 4859.1. This means they’ll need to be tested by an independent company in their retail form when they’ve been compressed for packing, rather than immediately after production.
System vs product R-values
There are two ways in which R-values are listed:
- System R-value includes the insulation value of air spaces and building materials working in conjunction with the insulation material when it’s installed in the building according to the manufacturer’s specifications.
- Product R-value is the R-value of the product on its own.
When comparing prices be sure to compare products with similar-type ratings. As single-sheet foils have no R-value as a material on their own, they’re measured and labelled according to their system R-value.
Table 2: Insulation thickness for some specific R-values:
|
Thickness required to achieve |
| Material |
R = 2.5 (mm)* |
R = 3.5 (mm)* |
| Glasswool batt (low density) |
130 |
180 |
| Glasswool batt (medium density) |
100 |
140 |
| Polyester batt (low density) |
160 |
220 |
| Polyester batt (medium density) |
110 |
160 |
| Sheep’s wool batt (low density) |
150 |
210 |
| Sheep’s wool batt (medium density) |
110 |
160 |
| Sheep’s wool (loose-fill, low density) |
170 |
230 |
| Sheep’s wool (loose-fill, medium density) |
110 |
160 |
| Rockwool batt |
90 |
130 |
| Rockwool (loose-fill) |
90 |
130 |
| Cellulose fibre (loose-fill) |
100 |
140 |
| |
Table notes
Source: CSIRO, Building, Construction & Engineering (modified).
* Rounded to the nearest 10 mm.
Table 3: Climate and R-values:
| |
Recommended R - values |
| Climate type and example locations |
Roof / ceiling |
Wall |
| Cool temperate and alpine |
| Melbourne |
3.0 |
1.5 |
| Mount Gambier, SA |
3.0 |
1.5 – 2.0 |
| Ballarat, Vic |
3.5 |
1.5 – 2.0 |
| Canberra |
3.5 |
1.5 – 2.0 |
| Hobart |
3.5 |
1.5 – 2.0 |
| Thredbo, NSW |
4.0 |
1.5 – 2.0 |
| Hot humid and hot dry |
| Cairns, Qld |
0 – 3.5 (A) |
0 – 1.5 (A) |
| Townsville, Qld |
0–3.5 (A) |
0 – 1.5 (A) |
| Broome, WA |
0 – 4 (A) |
0 – 2 (A) |
| Darwin |
0 – 4 (A) |
0 – 2 (A) |
| Marble Bar, WA |
0 – 4 (A) |
0 – 2 (A) |
| Mount Isa, Qld |
0 – 4 (A) |
0 – 2 (A) |
| Tennant Creek, NT |
0 – 4 (A) |
0 – 2 (A) |
| Temperate and warm humid |
| Brisbane |
1.5 – 2.5 |
1.0 |
| Perth |
1.5 – 3.0 |
1.5 |
| Sydney |
1.5 – 3.0 |
1.5 |
| Alice Springs, NT |
1.5 – 4.0 |
1.5 – 2.0 |
| Bourke, NSW |
1.5 – 4.0 |
1.5 – 2.0 |
| Adelaide |
2.0 – 3.0 |
1.5 |
| |
Table notes
(A) The zero figure isn’t intended to suggest that no insulation is required. It indicates that insulation to reduce heat loss may not be cost-effective and can even contribute to overheating in homes without adequate sun control. In these situations use insulation that prevents heat gain without unduly restricting heat loss (high down values, low up values).
Reproduced with kind permission from Your Home Technical Manual . |