Solar Air Conditioning in Perth — Can You Run AC on Solar?

Perth has the highest solar irradiance of any Australian capital city — and peak air conditioning demand coincides almost perfectly with peak solar generation hours. This makes Perth an ideal location to offset AC running costs with rooftop solar.

How Solar Reduces AC Running Costs

When your solar panels generate electricity during the day, that power is used directly in your home before any excess is exported to the grid. Running your air conditioner during solar generation hours (roughly 9am–4pm in summer) means you're cooling your home at close to zero cost — rather than paying the grid rate of $0.30–$0.35 per kWh in WA.

The key is load shifting: run your AC during peak generation hours and pre-cool your home before evening, when solar production drops. A home with good insulation holds cool air for several hours, meaning you may not need to run the AC much in the evening at all.

Sizing Your Solar System for Air Conditioning

A 6.6kW solar system (the most popular size in Perth) generates enough electricity on a clear summer day to run a 5–6kW split system and still export excess power. If air conditioning is a primary motivation for adding solar, a 10kW system provides a larger buffer and better offsets larger ducted systems.

Battery Storage

Adding a home battery allows you to store solar energy generated during the day for use in the evening when you might want to continue running the AC. Perth's Synergy network has specific rules about battery export, so consult a licensed solar installer before purchasing. The payback period for batteries is longer than for panels alone — typically 8–12 years — but prices are falling.

Real Savings in Perth

Perth homeowners with a 6.6kW solar system commonly report summer electricity bills of $50–$150 per quarter despite running split systems extensively — compared to $400–$600+ without solar. Results vary depending on system size, shading, roof orientation, and usage patterns.