Ducted gas changeover to reverse-cycle in Pakenham.

The first big housing estates on the eastern fringe of Pakenham — Cardinia Lakes, Lakeside, Heritage Springs and the early Officer release areas — went up in a tight 2002–2008 window. The standard spec at the time was a 3 or 4-star gas ducted furnace (mostly Brivis, Braemar and Bonaire), and most of those units have just rolled past their 18th birthday. Heat exchangers crack, igniters fail, gas valves stick. We’re getting two or three end-of-life ducted calls a week now out of that one corridor.

At the same time, the Victorian Energy Upgrades (VEU) scheme has shifted hard against new gas. Replacing a dead gas furnace with another gas furnace gets you no rebate. Replacing it with a high-efficiency ducted reverse-cycle inverter, and decommissioning the gas connection, attracts a point-of-sale discount in the $1,000–$3,500 range for a typical 4-bedroom Cardinia home (the exact figure depends on the climate-zone multiplier, the COP of the new unit, and the star rating of the dead unit being removed). That’s why so many Pakenham households are landing at the same decision point at the same time — the furnace dies, and the maths on changeover suddenly works.

The honest changeover process.

A real ducted-gas-to-reverse-cycle changeover is not a one-day swap, and any quote that says it is should worry you. Done properly, this is the sequence we run on every Cardinia changeover:

• Heat-load survey: room-by-room kW calculation (orientation, glazing, insulation, ceiling height) — not floor area times a multiplier. A 4-bed Cardinia Lakes home typically lands at 12–16 kW total.
• Duct audit: physical crawl through the roof cavity, measuring duct diameters, checking flex condition, insulation R-value (R1.0 minimum, R1.5 preferred), and joins. Old ducts undersized for cooling get flagged here.
• Switchboard check: a ducted RC inverter draws 25–40 amps on start, so we check breaker capacity, supply main, and any solar-inverter interaction under AS/NZS 4777 before committing.
• Gas cap-off: a VBA-licensed gas-fitter caps the line to AS/NZS 5601, pressure-tests the cap, and issues the gas compliance certificate.
• Refrigerant install: ARC-licensed installer brazes the line set (R32 refrigerant on most 2026 units), pressure-tests to 4.15 MPa, vacuums to under 500 microns, then commissions.
• VEU paperwork: we lodge the certificate with the accredited provider so the rebate is netted on your invoice — you don’t chase the money later.

What we install and why.

For ducted reverse-cycle changeovers in Pakenham we mostly fit Daikin Premium Inverter, Mitsubishi Heavy Industries Bronte, and Fujitsu SET series. All three run R32 refrigerant (lower global-warming-potential than the old R410A), all three modulate down to 25–30% of rated capacity (so they cycle less and run quieter), and all three have a published COP of 4.0 or better in heating mode — meaning $1 of electricity buys roughly $4 of heat. That’s the figure that makes the running-cost comparison against gas finally win in Victorian winters.

VEU rebate — what you actually get.

We see a lot of confusion about the rebate, so here is how it really works in 2026 for a Pakenham ducted changeover. The VEU scheme issues Victorian Energy Efficiency Certificates (VEECs) for each installation, and an accredited provider buys those certificates from the installer. The installer then passes that value through as a discount on the invoice. For a 12 kW ducted RC replacing a 4-star gas ducted unit in a 4-bed home, that discount typically sits between $1,000 and $3,500. Bigger gas unit being decommissioned, higher-COP replacement, and a colder climate-zone multiplier all push it toward the top of the range. We confirm the exact figure on your quote before you commit — not after install.

Solar PV interaction — AS/NZS 4777.

A lot of Pakenham homes built since 2015 already have a 6.6 kW or larger rooftop solar array, and a ducted reverse-cycle inverter pairs well with that — running the system on solar surplus in the middle of a hot day is essentially free cooling. But the interaction has to be checked under AS/NZS 4777.2, which governs how the solar inverter behaves under load and voltage shifts. We check the existing solar inverter’s rated capacity, your main switchboard rating, and the network operator’s export limit (5 kW single-phase is common in Cardinia Shire) before we sign off on a ducted RC sizing. On older 4 kW solar installs we sometimes recommend a smaller 10 kW RC rather than a 14 kW — the electricity bill works out the same because more of the load lands on solar.

2026 changeover pricing — Pakenham.

10–12 kW ducted RC, reusing serviceable ducts: $13,500–$15,500 before rebate. 14–16 kW for a larger home: $16,000–$19,500. Full new ductwork (where the gas ducts are unusable): add $3,500–$5,500. Most customers in Cardinia Lakes and Lakeside land between $12,000 and $15,500 net of rebate. Worked example: a 4-bed Lakeside home, 12 kW Daikin Premium Inverter, 18-year-old Brivis decommissioned, 80% duct reuse — $14,200 list, $2,400 VEU rebate, $11,800 invoiced.