Solar panels and tax deductions: what Australian homeowners and investors need to know

Solar panels save money on electricity bills — but they're not a tax deduction for personal use. The ATO treats solar panels as a capital asset, not an expense, which means they affect your tax position differently depending on how your property is used.

This article provides general information only. Your personal tax situation depends on your specific circumstances — consult a registered tax agent for advice.

Solar on your own home (private residential use)

No immediate deduction: Solar panels installed on your primary residence are not deductible. They're a capital asset used to reduce a personal expense (electricity), and the ATO does not allow deductions for personal capital expenditure.

Capital gains implications: When you sell your home, if it was your main residence for the entire ownership period, the main residence CGT exemption applies — the solar panels are part of the house value and excluded from CGT.

If you used part of your home for income-producing purposes (e.g. a home office, or renting out a room), a proportion of capital expenditure including solar panels may affect your CGT calculation. This proportion depends on the floor area and time used for income production.

The bottom line for homeowners: Solar panels reduce your electricity costs, which reduces your living expenses — valuable, but not a tax deduction. The financial benefit is the bill reduction itself.

Solar on an investment property

Investment property solar is tax deductible: If solar panels are installed on a rental property, the cost is deductible — but not all at once. Solar panels are a "depreciating asset" for tax purposes, subject to the capital works or depreciation provisions.

How depreciation works: The ATO has two relevant provisions:

Division 43 (Capital Works): Structural improvements to a building depreciate at 2.5% per year over 40 years. Solar panels are generally treated as a capital works item on a residential rental property.

Example: $8,000 solar system on a rental property → $200/year deduction (2.5% of $8,000).

Division 40 (Depreciating Assets): For small business or commercial use, solar systems can be claimed under Division 40 as depreciating assets, using the effective life (ATO Tax Ruling TR 2023/1 sets effective life for solar panels at 20 years, inverters at 12 years).

For residential rental properties, the lines between Division 40 and 43 are blurry for solar — a quantity surveyor or tax agent can advise the most advantageous treatment for your situation.

LMITO/LITO eligibility: Solar installation expenses on rental properties are included in net rental income/loss calculations, which affects your taxable income normally — there's no special solar credit.

When investment property solar makes sense from a tax perspective:

• The deduction is spread over 40 years (2.5%/year), so it's modest per year
• The electricity bill reduction benefits the tenant (or the landlord if included in a gross rent arrangement)
• The primary financial case for rental property solar is property value/rentability, not the tax deduction itself

Solar for small business (commercial or business premises)

Small Business Instant Asset Write-Off: Eligible small businesses (turnover under the relevant threshold — check ATO for current year thresholds) may be able to immediately write off the full cost of a solar system in the year of purchase under the Small Business Instant Asset Write-Off provisions.

For financial years where the instant asset write-off applies, an $8,000 solar system on a business premises can generate an $8,000 deduction in year one (rather than 2.5%/year under capital works).

The threshold and eligibility changes frequently: Instant asset write-off thresholds and eligibility have changed almost every year from 2014 to 2026. Always check the current ATO guidance or ask your tax agent before assuming the write-off applies to your situation.

Standard depreciation (for businesses not eligible for instant write-off): Business solar panels depreciate at 10%/year under the diminishing value method (effective life of 20 years for panels, 12 years for inverters per ATO effective life schedules). Over the first 5 years of the system's life, this provides meaningful annual deductions.

GST on business solar: If your business is registered for GST, you can claim input tax credits on the GST component of the solar installation cost. Solar installations by CEC-accredited installers include GST at 10%.

STCs (Small-scale Technology Certificates) and tax

STCs reduce the upfront cost of solar installation — installers typically apply them as a point-of-sale discount. For tax purposes:

Investment properties: The STC benefit reduces the cost base of the asset. If STCs reduced your $10,000 system to $8,500, the depreciable base is $8,500, not $10,000.

Businesses: The STC discount reduces the claimable cost for depreciation or instant asset write-off. The net cost after STCs is the tax-relevant figure.

Battery storage and tax

Battery storage follows the same rules as solar panels — it's a capital asset, not an immediately deductible expense for homeowners. For investment properties and businesses, the same depreciation rules apply. The ATO effective life for home battery systems is 10 years.

Key questions to ask your tax agent

• For investment property solar: is the system treated as Division 40 (depreciating asset) or Division 43 (capital works) for maximum benefit?
• For business solar: does my business qualify for the instant asset write-off this financial year?
• What is the correct tax cost base after deducting STC benefits?
• How do I apportion deductions if the property has mixed personal/income-producing use?

Solar panels are a financial asset that pays back through reduced electricity bills — the tax treatment is secondary for most Perth homeowners. Investment property and business owners have more meaningful tax benefits to capture, worth structuring with a qualified tax agent.