Questions to ask your builder

A builder hammering on a house frame against a blue sky

Whether you're planning a renovation or a new build, we've put together a guide to help you select a builder and ask the right questions to ensure you have an energy efficient home that works for you and the planet.

Questions to ask your builder

Air sealing and ventilation

• Should you consider a blower door test?

A blower door test is the most accurate way to measure the current air leakage of your home. If you are undertaking a renovation, this test can also be conducted after the renovation to measure the improvement.

• Can your builder guarantee appropriate air sealing levels?

Efficient air sealing will require your builder to oversee the installation of air sealing products to ensure that they are installed correctly. Ask your builder whether they can guarantee quality air sealing.

• Can trades work together to seal the vapour barrier?

Your builder will install your vapour barrier before electricians and plumbers finish their final installation. The builder should ensure that the trades work together and seal any gaps and cracks with tape and glue to maintain a strong seal.

More about air sealing and ventilation
Hot water

• What energy sources are available to me?

There are three main energy sources for your hot water – electric, gas and solar.

• Do I need to replace 'like with like' or can I get a different system?

It is possible, and often wise, to replace your hot water system with a different, more energy efficient system. If you currently have an electric hot water heater, you could replace it with:

  • a high-efficiency natural gas/LPG continuous flow hot water heater
  • a high-efficiency natural gas/LPG storage hot water heater 
  • a natural gas/LPG-boosted solar hot water heater 
  • an electric-boosted solar water heater 
  • a heat pump hot water heater.

If you currently have a gas hot water heater, you could replace it with:

  • a high-efficiency gas continuous flow water heater 
  • a high-efficiency gas storage water heater 
  • a gas-boosted solar hot water heater. 

• Which systems will suit my climate?

Solar hot water systems work best in the warmer, northern parts of Victoria, but will still perform well in the cooler, southern regions. A solar hot water system is more expensive to buy and install, but the running costs will be significantly lower. Gas hot water systems and electric hot water systems are suited to all climates, but gas systems are the most economical.

• How much hot water does my household require?

A typical household uses around 40–50 litres of hot water per person per day. Our hot water running costs table compares the annual running costs for various types of hot water systems for a range of households.

Hot water running costs

• What are the purchase costs and running costs of different system types?

A solar hot water system is more expensive to buy and install, but the running costs will be significantly lower. Gas systems are generally more economical to run than electric systems, but electric systems are generally cheapest to buy.

• What are the costs and benefits of storage or continuous flow systems?

A storage heater that is too small will continually run out of hot water, while one that is too large will be more expensive to run because it will maintain the water temperature even when it is not being used. Similarly, a continuous flow system that is too small may not be able to keep up with your hot water demands when multiple hot water outlets are being used at the same time. Our hot water running costs table compares the annual running costs for various types of hot water systems for a range of households.

Learn more about hot water

Insulation - ceiling

• Will your installer take appropriate safety precautions?

Some types of insulation require specialised equipment and fire prevention measures. Your installer should be able to advise you of the appropriate safety precautions for your walls when you obtain a quote.

• Is it possible to install the insulation in my home?

It may not always be possible to install insulation into all roof spaces with even coverage. The pitch of the roof may be too shallow, with heating or cooling systems and ducts blocking easy access. Ask your builder or installer if they think it will be possible to get access to your existing roof space.

• Can your installer guarantee good coverage?

Ask the installation company whether or not all sections of your ceiling will be insulated and whether or not they can guarantee good coverage. Some companies will undertake surveys with infrared cameras before and after installation to check that it has been properly installed, or may provide this service as an optional extra. To be effective, the thermal imaging needs to be undertaken when there is a reasonable temperature difference between the inside and outside of the house – either on a hot summer day or a cold winter day when heating is operating.

More about ceiling insulation
Insulation - floor

• Will your installer take appropriate safety precautions?

Some types of insulation require specialised equipment and fire prevention measures. Your installer should be able to advise you of the appropriate safety precautions for your walls when you obtain a quote.

• Will the insulation be correctly installed?

You builder or installer should take care to ensure that the installation does not compromise the quality of your underfloor ducted heating system (if you have one). They should also make you aware of any possible condensation issues in the underfloor space.

• Can your installer guarantee good coverage?

Ask the installation company whether or not all sections of your ceiling will be insulated and whether or not they can guarantee good coverage. Some companies will undertake surveys with infrared cameras before and after installation to check that it has been properly installed, or may provide this service as an optional extra. To be effective, the thermal imaging needs to be undertaken when there is a reasonable temperature difference between the inside and outside of the house – either on a hot summer day or a cold winter day when heating is operating.

More about floor insulation
Insulation - wall

• Will your installer take appropriate safety precautions?

Some types of insulation require specialised equipment and fire prevention measures. Your installer should be able to advise you of the appropriate safety precautions for your walls when you obtain a quote.

• Is it possible to install the insulation in your home?

It may not always be possible to install pump-in insulation in double brick walls. In some cases there is not sufficient space between the bricks, or the space may be too cluttered to allow suitable insulation. Installation companies should be able to advise you of the suitability of your walls when you obtain a quote.

• Will the insulation be correctly installed?

Your builder or installer should take care to ensure that the insulation product supplied is less than 90mm high, so that the insulation is not compressed when installed. For weatherboard houses they should also recommend a type of building paper, house wrap or reflective foil, to separate the insulation from the weatherboard in order to avoid condensation.

• Can your installer guarantee good coverage?

Ask the installation company whether or not all sections of your external walls will be insulated and whether or not they can guarantee good coverage. Some companies will undertake surveys with infrared cameras before and after installation to check that it has been properly installed, or may provide this service as an optional extra. To be effective, the thermal imaging needs to be undertaken when there is a reasonable temperature difference between the inside and outside of the house – either on a hot summer day or a cold winter day when heating is operating.

More about wall insulation
Passive solar design

• Is your architect, designer or builder integrating passive solar design principles into your home?

Passive design principles (PSD) principles harness the movement of the sun to create homes that are sunny, bright and comfortable all year round. Using these design principles will make your new home or renovation more energy efficient and reduce your running costs.

Plan your new home or renovation to save energy and money.

Recommendations

• Do your architect, designer and builder all come with good recommendations?

Before designing your new home or renovation, ask your architect ,designer or builder to provide you with at least two recent projects, and clients that you can contact as referees. If saving money, improving your comfort and well-being are important to you, ask the referee whether your nominated professional integrates Passive Solar Design principles into their services.

Find the right renovation advice or, if you are undertaking a new build, read our guide on building for energy efficiency to save energy and money.

Sourcing materials

• Ask your builder about sourcing materials

Does your builder:

  • buy local materials to reduce carbon footprint
  • select materials that don't have toxic elements and can be recycled and reused
  • source timber from sustainable plantations and buy local materials to reduce carbon footprint. 
Waste minimisation

• Does your builder plan for waste minimisation?

Ask your builder about waste minimisation strategy and documentation. Victoria has 'towards zero' waste strategy documents which set state-wide targets for waste reduction, resource recovery and littering.

Windows

• What is the specified U-value of the windows?

If you're renovating or building, your windows may require an energy rating. Your supplier should ensure that the U-value supplied matches the required U-value stated on the energy rating. The lower the U-value, the better.

• How will the windows be shaded in summer?

External shading is vital to stop the hot summer sun from entering your home through your windows. This will keep your home significantly cooler during the summer months and may reduce your energy costs.

• What is the material of the window frame?

Your supplier should ensure that the window frame meets your specifications. If aluminium is selected, check that the window has a thermally broken aluminium frame.

• What is the frame-to-glass ratio of the windows?

The frame-to-glass ratio of a window will affect its energy efficiency. Choose a thin aluminium or metal frame, and thicker timber or uPVC frames.

Learn more about windows
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