Operation Household Energy Reduction: Part 7 - Ceiling Insulation and Ventilation

I have written previously about our work to insulate the cathedral ceiling portion of the house. The flat ceiling portion had fibreglass bats installed over it to an average depth of 100mm with no insulation over several major cupboard areas. The maximum thermal resistance value of the old insulation where fitted was R2.0.

We undertook the following works to increase the thermal resistance values to R5.9 in summer and R5.2 in winter:

• fitting of polyester R3.5 bulk insulation to all uninsulated areas
• fitting of polyester R2.0 bulk insulation over existing insulated areas
• fitting of concertina foil batts over the top of the bulk insultation to reduce direct ambient heat/cold contact with bulk insulation to increase its effectiveness.

Because of the pitch and positioning of the roof we also were aware of very high heat build up within the roofspace on high temperature days and so installed a mains powered roof ventilator adequate in performance for a roof space slightly larger than ours.

Here, for those reading for the first time, are the caveats relating to our work on our house:

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.