Keep gas ducted heating and add splits, or go ducted reverse-cycle?

Many Melbourne homes have a gas ducted heater that still works and no cooling at all. After a run of hot northerly days in January, cooling goes on the list, and the question becomes whether to add to what is there or replace it with one system that heats and cools.

There is no single right answer, but there is a pattern. The heater's age and condition, how many rooms you want cooled and what is in the roof decide most cases. Victoria's direction on gas matters too, though less than many owner-occupiers expect.

If the heater is reasonably young, has been serviced and heats the house well, replacing it just to add cooling throws away a working system. A reverse-cycle split in the living area, and perhaps the main bedroom, gives you cooling where it counts with far less disruption than a full ducted change.

Those splits heat too, and efficiently. Many households end up using the living room split on mild winter evenings and saving the gas ducted heater for the coldest nights. That spreads the load and can stretch the heater's life until you are ready to change.

The catch is upkeep. Energy Safe Victoria recommends servicing ducted gas heaters every two years, with a carbon monoxide test at the vents in every room, and the splits need their own care. Two systems mean two sets of servicing, and the gas supply charge stays on your bill.

If the heater is getting old, has needed several repairs or has a major part failing, put the money into ducted reverse-cycle rather than another round of gas repairs. The same applies if you want cooling in most rooms. By the time you are looking at four or five splits, one zoned ducted system is usually the tidier answer.

Running costs favour the change as well. Reverse-cycle systems move heat rather than make it, and federal energy guidance says ducted reverse-cycle, while less efficient than wall units, is still more cost-efficient than gas heating. If the gas heater comes out, a licensed gasfitter disconnects and caps the gas.

This is where quotes often differ. Many older gas systems push warm air up through floor vents from ducts under the house. Warm air rises, so that works for heating, but cool air falls, and floor vents are poorly placed for cooling. Most reverse-cycle ducted systems go in the roof with ceiling outlets.

Roof ducts from a gas system can sometimes stay if they are intact, sized for the new unit and insulated to at least R1.5 with sealed joints. Crushed, torn or thinly insulated ducts cost comfort every day, so have every run inspected before comparing a reuse quote with a new-duct quote.

In an owner-occupied home, you aren't required to switch gas space heating to electric, although the government encourages it. The firm change from 1 March 2027 is for gas hot water that breaks and can't be repaired. So the heating decision can follow the heater's condition rather than a deadline.

Rentals are different. From 1 March 2027, when a rental's fixed heating fails and can't be repaired, it must be replaced with an energy-efficient fixed electric heating system with an outlet in the main living area. Landlords with an ageing gas ducted heater may prefer to plan that change rather than make it in a hurry in July.

Either way, have the switchboard and supply checked once, for the system you will end up with, so splits added now don't crowd out ducted later.