Quick Answer
Ducted evaporative cooling installation in Melbourne costs $3,500–$8,500, including the rooftop unit, ductwork, ceiling vents, and wall controller. A single-room portable evaporative cooler costs $400–$1,200 and requires no installation. Ducted evaporative cooling is significantly cheaper to run than refrigerated air conditioning — $0.05–$0.15/hour vs $0.40–$1.00/hour.
Evaporative cooling is Melbourne’s most cost-effective summer cooling technology for the SE suburbs, where summer temperatures regularly hit 35–42°C and dry northerly winds are common. Unlike refrigerated air conditioning, evaporative cooling works best when you leave windows slightly open — the opposite of what most people expect. This guide covers installation costs, running costs, maintenance, and whether evaporative cooling suits your home in 2026.
Complete Evaporative Cooling Cost Breakdown
System Costs by Type
| System Type | Unit Cost | Installed Total | Best For |
|---|---|---|---|
| Single-zone ducted (small, up to 20 squares) | $1,800–$3,000 | $3,500–$5,500 | 3-bed homes, single level |
| Single-zone ducted (large, 20–30 squares) | $2,500–$4,500 | $5,000–$8,500 | 4-5 bed homes, open-plan |
| Twin-motor ducted (large or 2-storey) | $4,000–$7,000 | $7,500–$12,000 | Large homes or 2-storey properties |
| Portable evaporative (single room) | $400–$1,200 | No installation required | Renters, supplementary cooling |
| Add zone to existing system | $500–$1,500 | $800–$2,000 | Expanding existing ducted system |
Installation Cost Breakdown
| Component | Cost | Notes |
|---|---|---|
| Rooftop unit and crane/lift | $1,000–$2,500 | Larger units (20+ squares) may require crane |
| Main duct from unit to ceiling | $300–$800 | Depends on roof pitch and ceiling cavity access |
| Ceiling vent registers (per vent) | $80–$180 | Most homes need 4–8 vents for even distribution |
| Flexible ductwork (per run) | $100–$300 | Connects main duct to each ceiling register |
| Wall controller + wiring | $200–$500 | Digital controllers add $100–$200 vs basic switches |
| Electrical connection | $200–$400 | Licensed electrician required for power connection |
Running Cost Comparison
| Cooling System | Running Cost/Hour | Annual Summer Cost* | Energy Rating |
|---|---|---|---|
| Ducted evaporative cooler | $0.05–$0.15 | $60–$180 | Very low — water and fan motor only |
| Split system reverse-cycle (6kW) | $0.25–$0.50 | $300–$600 | Moderate |
| Ducted refrigerated AC (14kW) | $0.80–$1.50 | $960–$1,800 | High |
| Portable refrigerated AC (2.5kW) | $0.40–$0.70 | $480–$840 | Moderate-high |
*Based on 4 hours/day, 3 days/week, November–March Melbourne summer.
Limitations of Evaporative Cooling in Melbourne
Evaporative cooling works by evaporating water to cool air — which means it works best in dry conditions. Melbourne’s climate is well-suited, with summer relative humidity typically below 40% during hot northerlies. However, there are limitations:
- Humid days: On days above 30% relative humidity (common during summer storms), evaporative cooling effectiveness drops significantly. A split system backup for the bedroom is a common solution.
- Fully sealed homes: Evaporative cooling requires air to escape — leave windows open 5–10cm on the leeward side. Homes sealed for noise or allergen control don’t suit evaporative cooling.
- Ash Wednesday-type fire days: On days with CFA fire restrictions, you may need to close windows — negating evaporative cooling’s ability to function.
Maintenance Costs
| Maintenance Task | Frequency | Cost | Notes |
|---|---|---|---|
| Cooling pad replacement | Every 2–5 years | $200–$600 fitted | Cellulose pads degrade with hard water deposits |
| Annual service (clean, oil, inspect) | Every year | $150–$300 | Before summer — clean sump, check pump, oil bearings |
| Water distribution spider replacement | Every 3–5 years | $50–$150 DIY | Plastic water distribution arms can split or block |
| Sump drain and clean | Every month in use | DIY — 30 minutes | Prevents algae, mineral build-up, mosquito breeding |
| Fan belt replacement | Every 5–8 years | $80–$200 fitted | On belt-driven units — direct-drive units don’t have belts |
Ducted Evaporative vs Ducted Refrigerated: Which Suits Melbourne?
| Factor | Evaporative | Refrigerated |
|---|---|---|
| Installation cost | $3,500–$8,500 | $8,000–$20,000+ |
| Running cost (summer) | $60–$180/year | $900–$2,000+/year |
| Works on humid days | No — effectiveness drops | Yes — humidity doesn’t affect performance |
| Works with windows open | Required | Works better sealed |
| Can also heat in winter | No — cooling only | Yes — reverse-cycle heating included |
| Maintenance complexity | Low — DIY-friendly | Medium — refrigerant requires licensed tech |
| Best climate | Hot dry summers — perfect for Melbourne north/NW winds | All climates |
Top 10 Tips and Gotchas
- Book in winter or spring — installation demand peaks in October–November. Booking in winter (now) gets you earlier installation and sometimes better pricing from installers filling quiet periods.
- Leave windows slightly open — 5–10cm on the opposite side of the house from the airflow direction. Fully sealed homes get no benefit from evaporative cooling.
- Service before summer — pads that dried out over winter can have mineral deposits that restrict water flow. A pre-summer service ensures full efficiency from day one of hot weather.
- Water quality matters — in hard water areas of Cranbourne, Officer, and Pakenham, mineral scale builds up on pads and in the sump more quickly. Monthly sump draining is essential.
- Pad direction — CELdek pads are more efficient than older Chiller pads but cost more. Worth specifying when the system is installed or pads are replaced.
- Fan speed vs pad control — on hot dry days, run the pad pump AND fan on high. On milder days, fan-only mode (no water pump) works as a whole-house fan for much less electricity.
- Duct sealing matters — poorly sealed duct joins lose cooling before it reaches the vents. Insist on all duct joins being taped during installation.
- 2-storey homes need twin motors — a single motor rarely has the pressure to cool both floors effectively. A twin-motor system or separate unit per floor is recommended.
- Check the roof structure — evaporative cooler units weigh 60–180kg. Your roofing contractor or builder can confirm whether your roof structure can carry the load without reinforcement.
- Consider a split system backup — for Melbourne’s humid storm days (and for sleeping comfort), a bedroom split system alongside the ducted evaporative covers the cases when evaporative cooling underperforms.
Local Melbourne Resources
- Seeley International (Braemar, Bonaire, Coolair) — Leading Australian evaporative cooler brands
- Breezair — Premium Australian-made evaporative cooler brand
- Reece HVAC — Trade supply for evaporative cooler parts and pads
- Bunnings — Pads, water distribution spiders, pump parts for DIY servicing
Frequently Asked Questions
How long does evaporative cooler installation take?
A single-zone ducted system takes 4–8 hours for a standard single-storey home. Larger homes or 2-storey properties take 1–2 days. No internal walls need to be opened — all ductwork runs through the roof cavity.
How often should I replace evaporative cooling pads?
Every 2–5 years in Melbourne, depending on water hardness and usage hours. In hard water areas (Cranbourne, Pakenham), expect replacement every 2–3 years. Blocked or crumbling pads can reduce cooling by 30–50% and increase energy use. Annual servicing should include pad inspection.
Can I run my evaporative cooler in winter?
No — evaporative coolers are cooling-only systems. For winter heating, you need a separate system (ducted gas, split system, wood heater). Some Melbourne homeowners run the evaporative cooler in fan-only mode (no water) in early autumn for low-cost whole-house ventilation.
Does evaporative cooling work with double-glazed windows or sealed homes?
Poorly. Evaporative cooling requires fresh air to exit the home through windows or vents. Fully sealed, double-glazed homes designed to hold conditioned air don’t suit evaporative cooling — refrigerated reverse-cycle is better suited to modern, highly insulated homes.
What is the lifespan of a ducted evaporative cooler?
Quality brands like Breezair and Braemar last 15–25 years with annual servicing. The motor is typically the first major failure, usually at 12–18 years. Replacement motors cost $400–$900 fitted — often cheaper than a new unit if the rest of the system is in good condition.
Final Thoughts
For SE Melbourne homeowners in areas like Berwick, Narre Warren, Pakenham, and Officer, ducted evaporative cooling remains the most cost-effective whole-house cooling solution in 2026 — provided your home is suitable (cross-ventilation possible, single storey or two-motor system on two-storey). The gap in running costs versus refrigerated AC is significant over 10+ years of ownership.
- Book installation in winter or spring — summer demand creates delays and price pressure
- Choose CELdek pads and digital controls for best performance
- Service annually before summer — it’s cheap insurance against a failure on a 42°C day
- Consider a bedroom split system as backup for humid summer storm days
