is the most cost-effective way to save on your energy bills. Most types of insulation are relatively inexpensive. The payback period or time it takes for the insulation to pay for itself through reduced energy costs is shorter than other, more expensive products.
You need to know about the different types of insulation to make the right choices for your home and climate. This guide will help you choose the right insulation for your home.
Insulation: the Basics
There are two basic types of insulation:
- Bulk insulation comes in a variety of forms. All types of bulk insulation have air pockets that help prevent heat transference.
- Reflective insulation works by reflecting heat away from the home interior.
Some types of insulation combine bulk and reflective insulation in one product.
Bulk insulation is rated by its "R-value." Bulk insulation with a higher R-value will give greater thermal efficiency. R-values can also be "up" values or "down" values. Up values are sometimes called "winter values" because they refer to the resistance of heat transference in an upward direction. A higher Up value will reduce the amount of heat that escapes from your ceiling. Down values are also called "summer values" because they refer to the resistance against heat entering your home.
#hiptip get acquainted with 'R-values' so that you know you're getting the most effective insulation for your home and climate
Reflective insulation also has R-value, but it must be installed properly to maintain an optimum R-value. Reflective insulation works best if there is a layer of air at least 25mm thick between the shiny aluminium surface and the wall or roof. The layer of air allows the insulation to do its job. Without the air layer, heat can transfer through the insulation and into the home.
The R-values of bulk and reflective insulation can be reduced if they are not installed correctly or deteriorate over time. Some types of bulk insulation eventually lose the bulk that gives them their insulating properties. Dust that settles on reflective insulation will reduce its R-value. Manufacturers recommend installing reflective insulation vertically or facing down to maintain its R-value over time.
Read: How much does insulation cost?
Types of Bulk Insulation
The most commonly used type of bulk insulation is fibreglass batts (also called glass wool). Many brands use formaldehyde, which has been linked with cancer. Look for formaldehyde-free batts or insist your insulation installer uses batts that do not contain formaldehyde.
The price of fibreglass batts will vary according to their R-value and other factors. For example, retail insulation suppliers might charge these approximate rates for these types of fibreglass batts:
- R2.0 batts cost around $40 for a roll that covers an 11 square metre area
- R2.5 batts with thermal and acoustic insulation might cost $65 for 7.0 square metre coverage
- R3.5 ceiling batts may cost about $90 for enough batts to cover a 14 square metre area
- R6.0 batts cost around $85 for 5.5 square metre coverage
#hiptip for most climates, an R2.5 value or higher is recommended
For most climates, R2.5 or higher is recommended. Formaldehyde-free batts may cost a little more, but are worth the extra investment because formaldehyde continues to be released into the atmosphere for years after installation.
Batt insulation can also be made from a variety of other materials, including:
- Rock wool (made from volcanic rock)
- Cellulose fibre (often made from recycled newspaper)
- Polyester (sometimes made from recycled plastic)
Batts made from these materials are generally more expensive than fibreglass (glass wool) batts.
While batts are most commonly used, another type of bulk insulation might serve your needs better. Some other options include:
Insulation panels are stiff sheets of insulation. They can have a higher R-value than batts, but can cost more. A single panel that covers a .72 square metre area can cost around $12.50. Insulation panels are often used in areas where batts aren't appropriate (under concrete slabs, for example).
Loose-fill (or blow-in) insulation is often used in attics and ceiling cavities. Loose-fill insulation can be made from fibreglass, cellulose fibre (often recycled newspapers) or wool. It is usually installed by professionals.
Spray foam insulation
Spray foam insulation comes in two forms: closed cell and open cell. Closed cell insulation has a higher R-value. You can buy cans of spray foam insulation to fill gaps around windows and other areas, but for large areas, it should be professionally installed. Spray foam insulation can cost three times as much as batts, but may be more appropriate for some areas. For example, if your cavity walls are not insulated, it can be injected through small holes.
Types of Reflective Insulation
Reflective insulation usually comes in rolls. It will have a reflective aluminium surface with paper or plastic backing. Other types of reflective insulation can come as sarking sheets or concertina or multi-cell batts, but rolls are most commonly used. The price will vary depending on the R-value and other factors:
- A roll of medium duty reflective insulation might cost around $110 for a coverage area of 80 square metres
- A roll of heavy duty reflective insulation can cost about $130 for the same coverage area.
- A roll of reflective insulation with a glass wool backing designed for installing under a metal roof may cost $85 for a coverage area of 18 square metres
Installing some types of insulation can be a DIY project, but professional installation is recommended - climbing into your roof, especially on a hot day should be left to a professional. While there will be labour charges, professionals buy their insulation in bulk at wholesale prices. They pass some of the savings on to customers and this offsets some of the installation cost. Having your insulation professionally installed can cost only 25 to 30 percent more than the cost of the insulation, making it very economical.
Cost aside, professionals know how to install insulation correctly. They will be careful not to allow gaps in the insulation. Gaps in insulation can significantly reduce its R-value. They will also be able to recommend the best type of insulation and the right R-value for your walls, ceilings and floors.
#hiptip the right insulation installed correctly will retain its R-value; your house will be cooler in summer and warmer in winter.
If you choose DIY installation, do your research first. Some common mistakes include:
- Selecting the wrong R-value for your climate
- Choosing the wrong type of insulation for your walls, ceiling, roof or floor
- Leaving gaps in the insulation or accidentally tearing reflective insulation
The right type of insulation installed correctly will retain its R-value. Your house will be cooler in the summer, warmer in the winter and your heating and cooling costs will be lower. Within a few years, you may save the total cost of your insulation. After that, your insulation will continue to save you money for years. So what are you waiting for? Get quotes for your insulation