Operation Household Energy Reduction: Part 8 - Wall Insulation

Because of the design of our house, we realised as we were doing this energy reduction work that it would be easy and relatively inexpensive to apply insulation material to our external walls. We chose Rockwool wall insulation that can (in the main, for a cavity brick house) be blown in by removing the roof tiles above the wall cavity. It has a thermal resistance factor of R2.5. The hose used in the process can generally reach around the nogging at the mid point of the wall and allows a good fill of the whole cavity.

Because most of our windows are of the floor to ceiling variety, there were very few cavities to be insulated that were not accessible from the roof. In those few cases where cavities were not accessible, bricks or weather boards are removed. When the bricks were removed, the company we used were attentive to grout colour matching upon replacement. Some putty and paint touch ups to timber work near the bricks was all that was needed to remove any obvious “interference.”

There are both Rockwool and synthetic products available to be blown in to wall cavities. It seems as a relatively new approach to insulation it is difficult to get clear evidence of what might be a “better” option. We chose Rockwool on the basis of recommendations from people whose opinion we respected plus our own research on cost, application process, fire retarding effect, safety of materials and other such considerations. That doesn’t make our choice law.

In terms of the effect of the insulation, the snugness of the house improves and need for mechanical heating and cooling continues to reduce ….and there are terrific noise abatement outcomes too!

Now, those caveats to all of this work – from previous posts - again….

1) whilst there are technical fixes that can contribute to energy reduction, we wanted to make sure that we didn’t concentrate exclusively on them. My gadget-attracted persona is fascinated with new photo-voltaic cell technology or the latest approach to circulating filtered warm ceiling air into the house. We have considered or are considering all of these approaches but prioritised actions according to the most significant thermal performance improvements for the lowest cost, specific to our home.

2) Related to this point, we are aware of the relative economic capacity we enjoy that allows us to make some of these changes simply.

3) So we want to avoid seeing this as a way we can “proof” our little home against the rest of the world. 90000 litres of localised water storage might be fine if it makes sense in the context of your local rainfall and reasonable water usage. It doesn’t make much sense if it is to safeguard your lifestyle while the rest of the world runs out of water.

4) And part of the reason for adding these thoughts to this blog is to add to the conversation about what is possible and keep us all thinking about ways we can contribute to this kind of work for ALL dwellings, regardless of personal economic capacity.

5) Our efforts are not necessarily particularly remarkable in the scheme of things, but its fun to tell the story, to be encouraged in what you are doing and to encourage others.

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