5 things to know about home insulation

 By Alex Brooks

With the federal government handing out free home insulation like lollies, it's important to know why insulation works and how much it should cost you.

The $1600 grant - check the details here - should be enough to install ceiling batts in most standard homes. Naturally, there's talk of insulation installers now overcharging and trying their best to extort more money out of unsuspecting home owners. Here's what you need to know:

1. Insulation is not created equal

Batts are the easiest form of insulation to retrofit into any home, with older-style Federation, bungalows and Victorian homes benefitting the most from ceiling insulation. It's easy enough to carry the batts into a ceiling cavity and fit them neatly between the timbers. What's not so easy is to work out which insulation material to choose - there are fibreglass batts, rockwool batts, wool batts, concertina batts and polyester batts. My preference would be for a natural material because fibreglass batts can cause problems in the future as the material breaks down and requires careful handling. You can also install loose insulation, such as paper, which can be pumped in to difficult-to-access roof areas. There are also air-cell materials which are easier to handle and extremely cost-effective and are great under timber floors.

2. What's the R value?

All home insulation products have an r-value, which indicates the insulation material's thermal efficiency. The right r-value for your home will vary according to your local climate and basic things like how many west-facing windows your home has, how much sunlight it gets and even the colour of your roof.  Unfortunately, r-values are a variable thing because your own home, the microclimate and roof style will create a microclimate unique to your dwelling. In Australia, there are suggested r-values for each climate zone, but if you have foil sarking in your roof, you need to be careful not to employ too high an r-value that could literally overheat your roof space in summer while keeping you warm in winter. R-values between 3 and 4 are recommended in Australia.

3. Why insulate?

It's like giving your house a cardigan that will keep it warmer in winter and cooler in summer. Insulation is the easiest, cheapest way for households to reduce the amount of energy they need to heat or cool their home.  Read more about the benefits here. Ceiling insulation is the lowest-cost, highest benefit way to reduce household greenhouse emissions. Oh, and it will make your house more comfortable to live in. It's the easiest way to offset the massive rise in electricity costs predicted over the next 10 years.

4. Is it easy to install yourself?

Batts are relatively easy, but installing fibreglass batts can be tricky and means you need protective clothes and goggles to protect your skin and eyes from the fibreglass particles. It's also a really HOT job and best done in winter. If you have iron-core downlights, it can be downright dangerous if you don't install the insulation batts correctly over the top of the old transformers. Many downlights are a fire hazard if insulation is installed over the top of them. It's also important to "chink" the batts and cut them up if they don't fit into the standard holes. You need to cover the entire ceiling for insulation to work well.

5. Check any installation by a pro, though

If you take advantage of the grant, it's important you check the job has been done well. Unethical installers might gamble that you won't get up into the roof cavity to check the batts are installed across the entire ceiling and are neatly trimmed and tucked in. For every 1 per cent of roof space not covered by insulation, there will be a 5 per cent reduction in effectiveness.