Energy Makeovers

The House

Kim and her family live in a detached double storey brick house with an established, well-kept garden. They were planning to renovate the house and add an extension to the rear of the house, and were looking to use this opportunity to make their house as energy efficient as possible. They were also interested in using their wide north-facing rear roof to install a solar PV (PhotoVoltaic) system as well as a solar hot water system.

Kim contacted Energy Makeovers and requested a comprehensive home assessment to be conducted to get informed on how her family were using energy. Their top three priorities were to reduce their carbon pollution*, improve comfort and save on their energy bills.

* CO2 emissions associated with electricity and gas usage.

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The Pain Points

Two of our expert assessors visited the property and conducted a thorough check of the premises and renovation plans as well as an interview with Kim. Their annual greenhouse gas emissions were 17 tonnes and energy bills were nearly $3,000 per year, of which gas comprised more than half. This unusually expensive gas bill was mostly due to gas used for heating in winter.

Our assessment found that the lack of effective weather sealing and insulation as well as ‘cold windows’ on the south of the house were impacting heavily on comfort and leading to the excessive use of gas heating, costing $1,330/yr in heating. Similarly, the top floor rooms were uncomfortably hot in summer. Not surprisingly, the home energy rating for the house was found to be 1 star (out of 10).

Our Recommendations

Based on our assessment we compiled an Energy Makeovers Roadmap report for Kim, containing detailed information on their energy usage and recommendations on suitable home improvements. Projects were costed using quotes received from our trusted suppliers and installers and ranked by cost-effectiveness.

The best bang for buck was weather sealing of the exterior doors, wall vents, chimneys and exhaust fans, which costed $3,334 to install and saved $559/yr in heating and cooling, therefore paying for itself in 6 yrs. This immediately gave an energy rating improvement of 2 stars, while reducing carbon emissions by 18%.

We also recommended topping up the roof insulation to R3.5 and adding R2.5 insulation to the floor, thus decreasing heat loss. Although the report found that replacing all windows with double glazing would not be cost-effective at current prices, Kim decided to install double glazing for their new extension, reasoning that it would affect their comfort in the long run.

Replacement of the halogen down-lights and the old fridge with energy efficient products was also recommended. Furthermore, a solar hot water system and solar PV system were sized, costed and presented in the Energy Makeovers Roadmap report, giving the option of either a 1.5kW or 3kW PV system, which would both pay for themselves in less than 10 years.

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The Benefits

With all the recommended projects being implemented (including a 1.5kW PV and solar hot water system), we estimated Kim would save more than 60% on their total energy bills. The thermal shell projects (including weather sealing, insulation and Magnetite glazing) would cost a total of $11,883, saving $806 every year and paying for themselves in 15 years. It would increase the home’s energy rating to 4 stars and cut greenhouse gas emissions by 28%.

The impact to the family’s comfort would be substantial (see figure below) – during a cold winter day, the inside of the house would be up to 5 degrees C warmer. Furthermore, with the introduction of residential mandatory disclosure of energy ratings in May 2011, the value of the property is expected to increase by 4.5% or $105,525 in this case.

Kim was delighted that the Energy Makeovers Green Button, requested with the report, had quotes and offers from our trusted installers for the recommended projects, counting all government incentives available. She contacted their architect straight away to include these projects to their overall renovation plan.

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