Conservation comment: Smart renovations can save homeowners serious money

The words economy and ecology are both derived from the Greek word oikos, which means home. Our home in Castlecliff is living up to this double billing by saving energy and money as a result of a substantial renovation of a 100-year-old villa we embarked upon in November of last year.
The economical and ecological success of this project results from a series of design principles that have guided us - along with the New Zealand Building Code - through the process. The principles can be divided into two categories: energy and matter. I'll use this article to explain our approach to energy conservation and a future article to explain our approach to resource conservation.
We've saved energy and money by incorporating passive solar design into the renovation and installing energy efficient products. Passive solar design relies on three components: solar gain, thermal mass and insulation. We increased the amount of sunlight entering our home in winter by adding windows to the north side and removing them from the south. What a difference it has made! We are reaching indoor temperatures well above 20 degrees on sunny July days. But one danger of passive solar design is the potential for overheating on the sunniest days. This is addressed by adding thermal mass inside the building to slowly absorb excess heat during the day and reradiate it at night. This can be tricky in a renovation, particularly with a home built on piles. We've added mass by putting an extra layer of gib on north-facing walls that receive direct sunlight, installing a cast iron bathtub in our sunny bathroom, and building a brick surround for our multi-fuel stove, which gets all-day sun in winter. As far as insulation goes, we've filled all exposed wall cavities as well as installing under-floor and attic insulation. We also make use of thermal curtains and pelmets.
The other ways we save energy include the use of energy-efficient light bulbs and appliances as well as solar hot water. In total, our compact fluorescent light bulbs, under-the-bench refrigerator, Energy-Star washer and solar hot water helped us achieve a power bill of just $17 for the month of June. Yes, June was mild, but that $17 included a line charge of 38 cents per day. In case you missed the recent headlines, inflation is at a 21-year high, with electricity up 8 per cent. That concerns my wife and me and I imagine it concerns other Wanganui residents, which is why we have been using this project as an educational tool in workshops, schools and in presentations to seniors.
If you would like to know more there will be a short presentation of this project at the monthly Wanganui Permaculture Gathering on August 17th at 6.30pm at the Whanganui Environment Base on Wicksteed St.
For more information contact: theecoschool@gmail.com or visit www.ecothriftydoup.blogspot.com