AIR CONDITIONING COSTS IN WA

2.5kW split (small room)

$1,200–$2,000

Supply and install

3.5kW split (medium room)

$1,400–$2,400

Supply and install

5–6kW split (large room)

$1,800–$3,200

Supply and install

7–8kW split (open plan)

$2,200–$4,000

Supply and install

Multi-head system (3 zones)

$5,500–$9,000

Supply and install

Ducted system (4br home)

$8,000–$18,000

Reverse cycle, supply and install

Installation only (split)

$400–$800

Electrician labour, unit supplied

Switchboard upgrade (if needed)

$600–$1,500

Additional circuit required

Sizing for Perth's climate — the most critical decision

Perth has extreme summer heat — days above 40°C are not unusual in January and February — combined with cool winters. This temperature range (often -5°C to +45°C effective temperature including radiant heat) is larger than most of Australia, and it drives hard on undersized air conditioners. A 2.5kW unit that might cool a bedroom in Sydney will struggle in a west-facing Perth bedroom in summer. Always ask for a heat load calculation for Perth conditions before accepting a sizing recommendation.

Installation complexity in older homes

Perth's post-war housing stock — brick and tile homes built from the 1950s to 1980s in suburbs like Balga, Mirrabooka, Westminster, Gosnells — often have limited roof space, no internal wall cavities suitable for pipe runs, and aging switchboards that need circuit additions. Installation in these homes costs more than in a modern brick veneer home with accessible roof space. Always get a site inspection before accepting a quote.

Coastal corrosion — the hidden warranty issue

Standard split system units installed within 1–2km of the coast in Perth will corrode faster than their warranty period unless specifically protected. Ask about "coastal" or "marine" grade units and fin coating treatments. This is particularly relevant for properties in Cottesloe, Swanbourne, Scarborough, City Beach, Trigg, Hillarys and South Fremantle. A corroded outdoor unit three years into a five-year warranty is a common dispute.

Brand and efficiency — the long-term cost

Perth homes run air conditioning heavily — 4–5 months of cooling plus heating year-round is common. A 1-star energy rating difference in a 5kW unit translates to roughly $150–$250 per year in electricity in Perth's hot climate. Over a 10-year lifespan, a higher-efficiency unit (Daikin, Mitsubishi Heavy, Fujitsu premium range) can save $1,500–$2,500 in electricity versus a budget brand, even accounting for higher purchase price.

Can you provide a heat load calculation for Perth conditions for this room?

Is this unit rated for coastal/marine environments (if near the coast)?

What is the energy star rating and estimated annual running cost in Perth?

Does my switchboard need a new circuit — is this included in the quote?

Do you hold both an ARCtick licence and an Electrical Contractor Licence?

Will a Certificate of Electrical Compliance be issued?

What warranty do you offer on workmanship, separate from the manufacturer warranty?

What is the pipe run length and are there any access issues that affect price?