Our context

When we finished full-time work around 2019 my wife and I decided to downsize from our Melbourne townhouse and moved to Apollo Bay. After a number of weekends inspecting established houses in our price range and failing to find anything that suited, we decided it would be more economical to buy some land and do a new build. We were happy do the work required for such a project and we valued the chance to create a home that would give us better value-for-dollar and more exactly met our needs especially having a home with energy efficiency credentials. By building new, we could build in high energy efficiency from the very beginning.

Our new home in the making at Apollo Bay, 2020

Our budget was modest and did not allow for the perfect passive energy home with a gold star energy efficiency rating. But we knew we could do much better than what the established homes we had seen on the local market were providing at the time.

Our motivations were mixed with environmental, economic and life-style drivers. And we had the benefit of previous good experience. In the early 2000s we built a small weekender cabin in the bush near Ballan which was off-the-grid. We learnt how to live there more simply with greater self-sufficiency. After a few years of oil lamps and bottled gas, we installed our first solar system with a battery bank and remember the joy of turning on the electric light for the first time! From then on we were advocates for using solar energy to power our home. We had no power bills, we were minimising our carbon footprint and we were learning to live with and adapt our behaviors to be in tune with the sun. As converts to the solar-way we also installed a solar system on our inner-city townhouse home. We lived with it for some years before deciding to relocate to the south west coast.

Planning to be energy efficient

To build-in energy efficiency into our new two storey home at Apollo Bay, the first step was to consult an architect to design the key foundation features of an energy efficient house. First was the physical orientation of the building. The land we had bought was a compromise location that had a natural east-west bias rather than a more ideal north facing orientation. We worked around this as much as possible and ensured the roof style gave us as much north, north-west exposures as possible for two solar arrays, and that major window facings would deliver north-west light and warmth in winter.

The windows were to be aluminium double-glazed. We chose middle-range options from Rylock in Geelong. They were not a top-end option like imported European-style triple-glazed casement windows. Nor were they the more expensive form of double glazing with thermal breaks or the even more effective uPVC double glazing. Our windows were another compromise we had to make, but the upside of that decision was that the dollars we saved enabled us to install internal window coverings with closed pelmets (roman blinds) that maximized the thermal performance of the double-glazed windows we had chosen.

A valuable step we took early in the planning stage was to have an energy efficiency expert review (Richard Keech of New Energy Thinking) our draft house plans and make recommendations. Out of that we discovered that the extent of glazing was too extensive and not at all compatible with high energy efficiency. We went back to the drawing board with the architect and reduced the window extent by 30%. Surprisingly this major change did not adversely impact on the building’s over all aesthetic nor deprive us neither of light or impressive views of the sea to the south and east nor the Otways forest to our north and west. The move did significantly reduce our double glazing costs!

Another opportunity for maximizing energy efficiency in a new build is insulation. Although our builder was not particularly driven by energy efficiency values, he accepted our request to install underfloor insulation. We asked for Ecomaster polyester underfloor rolls which he sourced and duly installed. All internal and external walls were fitted with 2.7R recycled glass-batt insulation and the ceilings were lined with 3.5R batts. This ‘blanketing’ with insulation contributed enormously to reducing leaks in the building envelope and to the building’s capacity to retain warmth in winter and coolness in summer. It also created an acoustic ‘softness’ in the house, despite the timber flooring.

Ecomaster polyester underfloor insulation came in rolls that were stapled to floor bearers

Bradford under roofing insulation blanket in place under roof decking

Kauf Earthwool Sound Shield R2.5 batts were used throughout the internal wall and R5.0 batts used in ceiling insulation

When we planned the electrics of the house, we pre-wired for the full electrification of the house from the beginning. We requested pre-wiring for a solar system and a battery installation later down the track. We requested circuits for several Nobo panel heaters down stairs, a large split system in the upstairs dining and living area as well as wiring for an induction electric cook top and for a Reclaim heat-pump hot-water system. We added large ceiling fans to the master bedroom and living area to assist with air flow in both the warmer and cooler months. Window and door sliding external doors locations were also part of the design to enable the uses of good natural air cross flows throughout the house.

When we planned the electrics of the house, we pre-wired for the full electrification of the house from the beginning. We requested pre-wiring for a solar system and a battery installation later down the track. We requested circuits for several Nobo panel heaters down stairs, a large split system in the upstairs dining and living area as well as wiring for an induction electric cook top and for a Reclaim heat-pump hot-water system. We added large ceiling fans to the master bedroom and living area to assist with air flow in both the warmer and cooler months. Window and door sliding external doors locations were also part of the design to enable the uses of good natural air cross flows throughout the house.

Living in an energy efficient home

We moved into the house towards the end of the first COVID pandemic crisis in early March 2021. At the end of that month a Geelong solar company designed, supplied and installed a 19 panel 6kW solar system. Our total electricity invoices for the Mar 2021- Feb 2022 year (autumn/ winter/spring and summer) amounted to $730.00 In late June 2022 Geelong RACV Solar group supplied and installed a 13 kWh Teslar Powerwall battery to work off the solar system.

How well did the combined solar and battery system work? We kept track of use and electricity costs, all made easy courtesy of the Teslar and Power Shop monitoring data. Our total electricity invoices for the first full year of the system – July 2002 to July 2023 year, was $575.00 (aver $47.90 per month). For several months we had an -in-credit account. This was at a time when solar feed-in tariffs were being reduced and per kwH power prices were increasing. More significantly our mains electricity supply use had fallen from 3,102 kWh in 2021-22 to 1,614 kWh in 2022-23 a decrease of 48%. Although the total dollar saving was not enormous, the new battery had also protected us from a number of the power blackouts that dogged Apollo Bay’s supply that year and, obviously, our demand on fossil fuel generated electricity and our contribution to emissions had significantly diminished.

After two years of living in our new home we assessed that all the energy efficiency work had been well worth it. The house was delightfully live-able in all seasons, our electrification of the house had reduced our power bills and we had substantially reduced our contribution to emissions.

What might we have done differently?

As I mentioned earlier we had to make some compromises and we might re-think some we did not make. One thing we did not compromise on which we might regret now is the decision to rely on a slow combustion Nectre wood stove for winter heating upstairs. Although the ambiance, aesthetics, primal joy and comfort of radiant wood fire is very hard to beat, it is really much harder to justify the emissions from such a form of home heating today. There are efficient electric radiant heater alternatives now available – such as the Finish LVI Purmo Parada oil filled panels with wi-fi control systems.

Actually living in the house for the first year we also discovered that the north-west facing eave on the top floor rear deck was not deep enough to protect the north-west facing windows from the months of late spring and early autumn sun. To address this design flaw we considered extending the existing eave or installing a pergola. We were advised by a local designer to avoid a fixed structural solution and to choose a more flexible alternative to increase adaptability to the variation of sun exposure in those ‘in-between’ months. So we decided to install two motorised external blinds – one an awning on scissor arms and the other a smaller drop-down blind – to deflect a direct hit of sun to the kitchen and study windows … when it was needed. It turned out to be the perfect and most economical solution.

Would we do it all again?

Well, yes … most definitely. First, because of the end result did give us more comfortable living, which is one of the energy efficiency promises; second, because the economics worked well – despite the considerable additional capital costs involved (e.g. double glazed windows, solar arrays and battery, extra insulation; split system and heat-pump hot-water) we were still able to build the new 2 storey, 3 bedroom energy-efficient house for less than what we were facing in buying an equivalent sized established home with much less energy efficiency (<$930K) AND we had built a buffer against ongoing increases in energy costs ; and third, we have substantially reduced our carbon contributions.

Two Happy Campers

07 Nov 2024