Solar and battery on a new build: getting it right
Solar is the most effective way to lift a new home energy score, and a battery takes it further. How to size it, where to put it, and why to itemise it in the contract.
If there is one upgrade that does the most for a new home energy score, it is solar, and increasingly a battery alongside it. Building is also the ideal time to do it, because the roof, the switchboard and the wiring are all still being set out, so everything can be designed to suit from the start rather than retrofitted later. The trick is getting the system sized sensibly for how you live, positioned on the right part of the roof, and written clearly into your contract so there are no surprises.
Why build time is the moment
Adding solar during the build means it is designed in, not bolted on. The roof pitch and the sections that catch the most sun can be planned around the array, the switchboard can be sized for it, and conduit for a battery or an EV charger can be run while the walls are open. Doing this up front avoids the compromises of a retrofit, where you take whatever roof and wiring you happen to have.
Sizing it for how you live
Bigger is not automatically better. The right system size depends on how much power you use and when, and whether you are an all-electric home running a heat pump hot water system and induction cooking, which lifts daytime and evening demand. A good installer sizes the array to your likely use and your roof, rather than selling you the largest system that fits. For the energy score, a well-matched system beats an oversized one.
Where the battery fits in
A battery stores the solar your panels make during the day so you can use it at night, which is when a lot of households draw the most power. That is why a battery lifts the Whole-of-Home score beyond solar alone. The federal Cheaper Home Batteries program supports the first portion of usable battery capacity, which makes build time an even better moment to include one. The battery needs a sensible, well-ventilated spot, so plan its location early rather than squeezing it in later.
Put it in the contract clearly
Solar and battery are exactly the kind of inclusion that gets fuzzy in a quote. Ask for the panel count and capacity, the inverter, the battery size if included, and who handles the grid connection, all itemised in the contract. Clear inclusions protect you from a vague allowance that turns into a variation later, and they let you compare what different builders are actually offering.
Designing solar and battery into a new home
- The strongest lever for your Whole-of-Home energy score
- Runs the home on power you generate yourself
- Roof, switchboard and wiring can be set up for it from day one
- A battery stores daytime solar for evening use
- Pairs perfectly with an all-electric home
- The roof layout and orientation need planning early
- A battery needs a sensible, well-ventilated location
- Panels on shaded or south-facing roof sections do little
- Worth itemising in the contract so inclusions are clear
Solar is the most effective lever for a strong new home energy score, and a battery extends it into the evening. Build time is the ideal moment because the roof, switchboard and wiring can all be designed to suit. Size the system to how you actually live, give the battery a proper home, and get every part itemised in the contract so the inclusions are crystal clear.
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Match me with 3 buildersCommon questions
Should I add solar during the build or later?
During the build is ideal. The roof layout, switchboard and wiring can all be designed for the system from the start, and conduit for a battery or EV charger can be run while the walls are open. Retrofitting later means working around whatever you already have.
Do I need a battery as well as solar?
A battery is not compulsory, but it stores daytime solar for evening use and lifts your Whole-of-Home score beyond solar alone. The Cheaper Home Batteries program supports part of the usable capacity, which makes including one at build time more attractive.
How big should my solar system be?
It depends on how much power you use and when, and whether the home is all-electric. A good installer sizes the array to your likely use and your roof rather than just fitting the largest system possible. A well-matched system does more for your energy score than an oversized one.
Why should solar be itemised in my contract?
Because it is easy for a quote to show a vague solar allowance that later becomes a variation. Ask for the panel count and capacity, the inverter, the battery size if included, and who handles the grid connection, all itemised, so you know exactly what you are getting.