Where can the battery actually go? The rules decide — not the brochure.
Every glossy battery photo shows a perfect wall. Australian standard AS/NZS 5139 has other ideas: no habitable rooms, hard clearances from windows and appliances, bollards where cars roam, fire barriers on shared walls. None of this should scare you off — but it decides which wall, and sometimes it decides the price. Here are the rules in plain language, and how to tell a quote that respected them from one that never asked.
Written by Juan Flinn, Content Editor · Reviewed by the Mission Green Energy Team · Published 5 September 2026
One standard picks the wall.
Every brand obeys it.
AS/NZS 5139 — updated by a 2025 amendment, mandatory since 19 December 2025.
The standard exists for one reason: home batteries are large lithium units, and if one ever fails, it must not be where people sleep, cook or escape. So placement is regulated the way switchboards and gas lines are — not left to taste. Tesla, GoodWe, Sigenergy, FoxESS: the logo changes, the rules don’t.
The practical consequence: the wall you imagined may not be the wall you get, and two identical systems on two identical-looking houses can carry different install costs, legitimately. The rules below are the reason — and knowing them is how you audit a quote.
Banned spots, clearances,
and the garage caveats.
The numbers that decide most homes.
Habitable rooms & hideaways
Bedrooms, living rooms, kitchens, studies — out. So are ceiling spaces, wall cavities, under stairs and under access walkways. No exceptions for slim batteries or nice cabinets.
600 mm sideways, 900 mm below
From openable windows and vents into habitable rooms, and from appliances — air con, hot water, EV chargers. Narrow exits (under 900 mm) need 600 mm; the 2025 amendment allows wide openings like garage doors closer, if about a metre of safe passage remains.
Friendliest spot, two catches
Non-habitable, so it usually complies. But in a car’s path a bollard or barrier is mandatory, and on a combustible wall backing a habitable room a fire barrier must run 600 mm each side, 900 mm above.
Why siting moves the price —
and when that’s honest.
Per-site costs are real. Surprise costs are a choice.
A failed clearance means a different wall, which can mean longer cable runs. A garage placement can mean a bollard. A shared wall can mean a fire barrier. None of these are padding — they’re what passing inspection looks like on your particular house. It’s exactly why our own proposals price the system and leave site compliance items to the inspection, quoted as named lines before any deposit — a flat “installation included” price across every house in the state is absorbing these somewhere, and it’s usually your somewhere.
The sequencing test is the whole game: inspection → named compliance lines → deposit. If money appears after the deposit for things a tape measure would have found earlier, that’s not the standard’s fault.
Four questions
before you sign.
Two minutes of asking beats a change order.
“Where exactly will it go?” A quote with no nominated location hasn’t engaged with the standard yet.
“What did the siting add?” Bollard, barrier, cable run — you want them as named lines, not folded into a round number.
“Send photos of my meter board and the intended wall with your quote notes.” Good installers already work this way; it forces the siting conversation before the deposit.
“Which standard governs placement?” The answer is AS/NZS 5139. Hesitation on that one tells you everything — and our install-safety checklist covers what to verify after the crew leaves.
Battery placement:
your questions, answered.
Usually yes — the garage is the compliance-friendliest spot in most homes because it isn’t a habitable room. Two conditions follow it in: if the battery sits where a car could hit it, a mechanical barrier or bollard is required; and if it mounts on a combustible wall shared with a habitable room on the other side, a non-combustible fire barrier must extend 600 mm each side and 900 mm above the unit. Both are real line items, which is why an honest quote prices the garage work at the site inspection rather than pretending every wall costs the same.
Habitable rooms: bedrooms, living rooms, kitchens, studies — anywhere people spend time. Also ceiling spaces, wall cavities, under stairways and under access walkways. This is the standard AS/NZS 5139, and it applies to the lithium batteries used in home storage regardless of brand. If a seller shrugs at putting a battery in a bedroom wall recess, the conversation should end there.
The working numbers: at least 600 mm sideways from windows that open into habitable rooms, from vents, and from appliances such as air conditioners, hot water units and EV chargers — and at least 900 mm below any of them. Exits narrower than 900 mm need 600 mm of clearance; a 2025 amendment added a sensible exception for wide openings like garage doors, provided about a metre of safe passage remains. Your installer measures this on the day — the point of knowing the numbers is spotting the quote that never asked where your windows are.
Often this exact standard. A longer cable run because the preferred wall failed a clearance, a bollard because the battery sits in the car’s path, a fire barrier because the garage wall backs onto a bedroom, a switchboard tidy-up the siting revealed. These aren’t padding — they’re the difference between an install that passes inspection and one that fails it. What matters is sequencing: a good installer inspects, then prices the compliance items as named lines before you pay a deposit — never as a surprise on install day.
Placement itself isn’t usually an insurance question, but compliance is. Home policies generally exclude loss caused by non-compliant work — so a battery installed against the standard hands your insurer a reason to look hard at a claim. Keep the compliance certificate and installer details with your policy papers, and tell your insurer the battery exists so your sum insured covers it. Our home insurance guide covers that side in full.
The licensed electrician certifies the work (your compliance certificate), and in some states independent inspectors audit battery installs — Victoria’s program inspections have caught and fined false certifications. Practical protection for you: photograph the finished install, keep the certificate, and if a wall placement ever looks odd against the clearances above, query it in writing. A compliant installer will happily show their measurements; the other kind gets defensive.
Where these figures come from.
Rules summarised from AS/NZS 5139:2019 including Amendment 1 (mandatory 19 December 2025) as published in industry guidance; your installer’s measurements on the day govern. We don’t publish system prices here — siting is exactly why.