How does add-on cooling work?
Seeley describes its add-on unit as a reverse cycle unit that runs in cooling mode only, moving heat from the indoor air to the outside. It says one can go in with a new heater, or be added later where the airflow and duct design suit.
Rinnai says its Brivis add-on works with a compatible ducted gas heating system and, in most cases, uses the existing ductwork and vents. It's a common setup in Victoria: in a 2021 JWS Research survey for the Victorian Government, 10% of home owners in gas areas mostly heated with gas ducted that had add-on cooling.
Will my heater take it?
Not every one will. Rinnai says compatibility depends on the age, model, capacity and condition of your heater and ductwork, and that a qualified technician is required to assess it. For its own brand, Rinnai says Brivis DualComfort works with the Buffalo and StarPro ranges.
Seeley says its add-on units can only go with specific Braemar ducted gas heater models, and that this Braemar product line has been officially retired. If you have a Braemar heater, ask what options are left for your model before anything else.
Why the ducts matter more for cooling
Rinnai says cooling performance depends on the size and condition of the ducting, and that existing ductwork may need modifications or upgrades. Ducts that were fine for winter heating can leave the far bedrooms warm in summer. Have the installer check every run, and see our page on ducts, vents and filters.
Add-on cooling or ducted reverse cycle?
| Add-on cooling | Ducted reverse cycle | |
|---|---|---|
| Heating | Your gas heater carries on | A heat pump does it, so gas heating goes |
| Ducts | The existing ones in most cases (Rinnai) | New ones: the ACT guide says gas ducts are too narrow |
| Servicing | The gas heater at least every two years (Energy Safe Victoria), plus the cooling unit | One system to service |
| Suits | A healthy, compatible heater with years left in it | A heater near the end, or a plan to get off gas |
Discounts and Victorian rentals
Don't assume a VEU discount. The VEU air conditioner categories, 6A to 6G, cover units that both heat and cool, and an add-on runs in cooling mode only, so check with an accredited provider before counting on anything.
Landlords: from 1 March 2027, a Victorian rental needs fixed cooling in the main living area when a new agreement starts or a lease goes month-to-month. For a ducted electric system, the standard is a Total Cooling Seasonal Performance Factor of 3.8 or above, so ask the installer for that figure.
Your homework, and the installer's
You can
- Find your heater's brand and model in its manual or on the controller.
- Note which rooms overheat in summer, and how long you plan to stay.
- Check the heater's last service date.
Leave to a licensed installer
- Checking compatibility with your heater model.
- Testing airflow and inspecting every duct run.
- Refrigerant work, which needs an ARC licence, plus the electrical connection.
- Siting the outdoor unit for access and noise.
What we'd do
Our take
If your gas heater is in good health, it's on the compatible list and the ducts check out, add-on cooling is a sensible way to get summer comfort through vents you already have. If the heater is old, the ducts are tired or you're planning to leave gas anyway, get a ducted reverse cycle quote alongside it. Either way, use someone who works on gas ducted heating and refrigerated cooling, because they have to judge both.
