Building a new home in Perth is one of the best opportunities to design solar and battery storage into your property from the start — rather than retrofitting it later. The decisions made during the build phase, particularly around roof design, switchboard capacity, and conduit pre-runs, determine what system you can install and how cleanly it integrates with your home.
This guide covers everything you need to discuss with your builder before lock-up, including recommended system sizes based on your expected electricity use, what your switchboard needs, backup power options, and the factors that affect final system cost.
Why New Builds Are Different to Retrofits
When solar is added to an existing home, it works around what is already there — roof obstructions, switchboard constraints, conduit runs through finished walls. On a new build, you get to plan around the solar system instead. That means a cleaner installation, fewer compromises on panel placement, and no cost for remedial electrical work after handover.
It also means the time to act is before your builder finalises the roof design and electrical plan — not after the slab is poured. The recommendations in this guide are most effective when communicated to your builder early in the design process.
Recommended System Sizes
The right system size depends on your expected electricity use. If you are building and do not yet have Synergy bills for the new property, current household bills are a reasonable starting point. Perth’s bimonthly Synergy bill cycle means you will receive a bill every two months.
System sizes are recommendations based on typical Perth household profiles. Final sizing should be confirmed once your builder provides the electrical plan and roof layout. All systems are solar + battery combined — Positive Energy Solutions does not install solar-only.
These sizes reflect real-world usage patterns across Perth homes. Higher bills typically indicate more daytime appliance use, larger homes, or existing or planned electric vehicles, heat pumps, and pool equipment. A Positive Energy Solutions consultant can discuss your specific situation and recommend the right configuration for your build.
What to Tell Your Builder: Roof Design
Before your builder finalises the roof plan, share the following recommendations. They cost nothing to implement at design stage and can significantly affect how much usable roof space you have for solar panels.
Keep north, east, and west faces clear
Antennas, roof vents, air-conditioning units, and other rooftop services should be positioned on the south-facing roof face wherever possible. The north, east, and west faces receive the most sunlight and should be reserved for solar panels. A south-facing location for these services is a smarter roof design at no extra build cost.
If south placement is not possible, ask your builder to position obstructions toward the edges of the relevant roof face. This keeps the centre of the face — where panels are most efficiently arranged — as clear as possible.
Limit the number of individual roof faces
Each additional roof face adds complexity to a solar array. Multiple hip lines, gables, and changes in pitch fragment the available panel area and increase installation time. Where your home design gives you a choice, a roof with fewer faces is a better solar foundation than one with many small sections.
What to Tell Your Builder: Electrical Pre-Runs
The single most important thing a builder can do to future-proof a new home for solar and battery is to install conduit runs before walls and ceilings are closed. Once the home is finished, running cables through finished surfaces is expensive and disruptive.
Single storey homes
For a single storey home, the conduit runs from the roof space to the switchboard are typically straightforward. If the inverter and battery will be located in the garage (the most common location in Perth), and there is no sub-board in the garage, your builder should install:
- 2 x 25mm AC conduit from the inverter location to the main switchboard
- 1 x CAT6 communications cable from the inverter location to the switchboard
Double storey homes
Double storey homes require conduit from the roof space to the switchboard, which is often located on the ground floor. Ask your builder to pre-install:
- 2 x 35mm heavy duty conduit from the roof space to the switchboard
This is significantly easier and lower-cost to install during the build than after. Without it, a double storey retrofit typically involves running cables through external walls or ceilings, which adds cost and can affect the finish of the home.
DC conduit from panels to inverter
In addition to the AC conduit from the inverter to the switchboard, DC cables run from the solar panels on the roof down to the inverter. The number and routing of these conduits depends on where the panels are located on the roof and how many strings the array is divided into. Positive Energy Solutions will confirm the DC conduit requirements once your roof layout and panel count are confirmed. These details become clearer when your builder provides plans.
Switchboard Requirements
Your switchboard needs to have sufficient spare capacity to accommodate the solar inverter and, where required, a consumption meter for export limiting. The requirements differ between single phase and three phase properties.
Single phase
In Western Australia, single phase connections are limited to a maximum 15 kW inverter capacity. Panel capacity can be increased up to 15 kW DC when DC-coupling a battery. A typical 15 kW single phase array uses 34 x 440W panels. Each panel is approximately 1.8m x 1.2m, so the roof needs to have sufficient contiguous space to accommodate an array of that size.
Three phase
Three phase connections can support up to 30 kW inverter capacity, making them well suited to larger homes with higher energy loads, EV charging, and pool or air-conditioning equipment. A consumption meter is required for any system with an inverter above 5 kW, and for any system that includes a battery — regardless of phase or inverter size. This is an export limiting requirement in WA.
Backup Power Options
New builds are an ideal time to consider what level of backup power you want from your solar and battery system. There are two options — essentials backup and full backup — and the right choice depends on your system size and priorities during a grid outage.
Backup Gateways are located next to the switchboard, not next to the battery. This is important for your builder to know when planning the switchboard location.
Essentials backup
Essentials backup keeps selected circuits running during a grid outage — typically the fridge, lights, modem, and a few power points. It does not power the whole home. This is available on 5 kW inverters (up to 2 circuits) and 10 kW three phase inverters (up to 3 circuits). It is the most common backup configuration for average-sized Perth homes.
Full backup
Full backup keeps the entire home powered during a grid outage. It is available on 10 kW single phase inverters (maximum 10 kW output during an outage) and 15 kW three phase inverters (maximum 5 kW per phase during an outage). Full backup is best suited to larger homes where a single backup circuit would not cover essential load, or where a medical device or home office makes whole-home continuity important.
Additional Cost Factors
Standard system pricing applies to straightforward installations on single storey homes with tile or metal roofs, short cable runs, and direct switchboard access. The following factors can affect the final installation cost and are worth flagging to your Positive Energy Solutions consultant early:
- Roof type: Tile, Klip-Lok, and concrete (Monier) roofs have different mounting requirements and affect installation time.
- Double storey: Higher access requirements and longer cable runs add to installation cost.
- Inverter to switchboard distance: Longer AC cable runs from the inverter to the switchboard increase labour and materials. Installing a sub-board in the garage during the build is the most cost-effective way to manage this.
- Three phase: Three phase installations involve more complex switchboard work than single phase.
- Multiple roof orientations: Arrays split across more than one roof face require additional design and mounting work.
- Panel tilts: Flat or low-pitch roofs may require tilt frames to achieve optimal panel angle.
- Roof access: Limited access situations — such as high rooflines or restricted site access — may require scaffold or elevated work platforms.
None of these factors are problems — they are just variables that affect the scope of the installation. The earlier they are identified, the more accurately Positive Energy Solutions can quote and plan your system.
Get a Quote for Your New Build
Positive Energy Solutions works with new build clients from the design phase through to installation and commissioning. The best time to reach out for an indicative quote is when you have your plans. This gives us the opportunity to provide roof design input, confirm conduit and switchboard requirements with your builder, and size the system around your expected energy use. Reach out again 3 to 6 months before lock-up for a confirmed quote tied to your handover timeline.
Visit the Positive Energy Solutions showroom or request a no-obligation quote online. Every system includes SunPower P-Series panels, a 10-year workmanship warranty, and Omnidian monitoring from day one.
What Positive Energy Solutions needs to install
When you are ready to proceed with installation, Positive Energy Solutions requires the following before work can begin:
- Synergy account details — your welcome home letter will include your NMI (National Meter Identifier), which Positive Energy Solutions needs for the grid connection application
- Permanent Western Power meter connected — the installation cannot proceed on a temporary construction meter
- Active internet connection at the property — required for inverter and battery monitoring setup
Having these in place before your scheduled installation date avoids delays and ensures commissioning can be completed on the day.
Related guides
- Before Your Solar Is Installed in Perth: What to Expect From Sign-Off to Installation Day
- How Much Solar Battery Storage Do I Need? Perth 2026 Guide
- How to Choose a Solar Installer in Perth: What to Look For (and What to Watch Out For)
- How to Read a Solar Quote in Perth: What Should Be There, What to Question, and Why Two Quotes Are Never the Same
Frequently Asked Questions
When should I contact Positive Energy Solutions during my new build?
The best time to reach out is when you have your house plans. At that stage Positive Energy Solutions can review the roof layout, confirm conduit and switchboard requirements with your builder, and provide an indicative quote based on the design. Plans give us everything needed to size the system accurately and brief your builder before construction begins.
To get an updated final quote ahead of installation, contact Positive Energy Solutions again approximately 3 to 6 months before lock-up. This is when construction timelines become clearer and we can lock in pricing and schedule the installation around your handover date.
Can I get solar without a battery on a new build?
Positive Energy Solutions installs solar and battery together as a combined system. A battery-only or solar-only installation is not part of our offering. This is a deliberate position: a solar and battery system together gives you the best return on your investment, and new builds are the ideal opportunity to include battery storage from the start rather than retrofitting it later at higher cost.
Does the builder need to do anything specific?
Yes — the two most important things are roof service placement and conduit pre-runs. Keep antennas, vents, and air-conditioning units off the north, east, and west roof faces. And install conduit from the roof space to the switchboard (and from the garage to the switchboard if there is no sub-board in the garage) before the home is closed up. Positive Energy Solutions can provide a simple briefing document for your builder if that helps.
What if my new home is three phase?
Three phase is common in larger Perth homes and is well suited to higher solar and battery capacity. The main differences are switchboard pole requirements (4 poles minimum, 6 with a consumption meter) and the mandatory consumption meter for inverters above 5 kW. Three phase systems also unlock higher system sizes — up to 30 kW inverter capacity — which is relevant for high-energy homes with EVs, pools, and heavy air-conditioning loads.
What backup power option should I choose?
For most Perth homes, essentials backup is sufficient. It covers the appliances that matter most during an outage (fridge, lights, modem, a few power points) at a lower system cost than full backup. Full backup is worth considering if your household has a medical device that requires continuous power, a home office where a power interruption causes serious disruption, or if you want the peace of mind that the whole home stays on regardless of grid status. Positive Energy Solutions can walk through both options during your quote consultation.
Can I add more panels or battery later?
It is possible within the constraints of your inverter capacity and available roof space, but Positive Energy Solutions recommends designing and installing the full system you need from the start. Adding panels or battery capacity later involves a second mobilisation, additional electrical work, and grid connection administration — all of which add cost that would have been avoided if included in the original installation. The most cost-effective approach is to size the system correctly upfront, particularly on a new build where the roof, switchboard, and conduit are all being set up from scratch. We will discuss your long-term energy plans as part of the initial quote so the system is designed for what you actually need — not the minimum that gets the job done today.
About the Author
Jason Wiktorowicz
Sales Manager, Positive Energy Solutions | Perth, WA
Jason has been at the centre of Western Australia’s energy transition for over a decade. As Orchestration Lead on Project Symphony — WA’s largest virtual power plant pilot — and Stream Lead on Project Encore, he worked directly with AEMO, Western Power and Energy Policy WA to shape how distributed energy resources connect and operate on the SWIS. That work included developing and rolling out CSIP-AUS, now mandatory for all new WA grid connections. He also led Emergency Solar Management (ESM), the first program of its kind in WA, VPP for Schools (VPP4S), which provided direct market benefits through Supplementary Reserve Capacity, and REBAR, the WA Residential Battery Rebate scheme.
His earlier career spanned Synergy, Infinite Energy and Curtin University’s Sustainability Policy Institute, where he co-authored peer-reviewed research on net-zero urban precincts, solar integration and peer-to-peer energy trading, published in the journal Urban Planning in 2018.
At Positive Energy Solutions, Jason leads sales with a focus on system design accuracy and long-term performance. Positive Energy Solutions installs solar and battery systems, EV chargers and heat pumps, and holds partner accreditations with Fronius, SigEnergy, iStore and SunPower. Connect with him on LinkedIn.
