Explainer: What’s the cheapest way to heat my house if I get off gas?

If you are yet to push the “heat” button on your reverse-cycle air conditioner, this winter might be the time to start.

Heating with your air con has rapidly become a thing: the modern way to heat your Australian home. Why?

Because it is often far cheaper, cleaner, healthier, and safer than burning gas, LPG, or wood.

It’s cheaper because your reverse-cycle air conditioner (aka “heat pump”) collects free renewable heat from the air outside your house, and then transfers that free heat to inside your house.

Two good things about free renewable heat are that a) it’s renewable and b) no one can bill you for it!

Cleaner – because in addition to the free renewable heat it collects from outside your house, the fans and compressor of your heat pump can be powered by renewable electricity generated on your own rooftop or out on the electricity grid.

In this way, heating with your air con, in addition to being economical, can be 100% renewable. No fossil fuels nor even expensive hydrogen needed.

Healthier and safer – because your reverse-cycle air con can heat your house while producing no poisonous carbon monoxide gas, nor contributing to asthma, and posing no fire risk.

No fossil fuels were used in the heating of this home

Every summer more Australian homes are fitted with reverse-cycle air conditioners. With summers getting longer and hotter, some homeowners and landlords are saying “enough is enough, it’s time to have some summer cooling”.

But when summer is over, too often the air con remote control is packed away and is not thought of again until the heat of summer returns.

If packing away the remote control is what happens at your home, you’re missing a big opportunity. Studies (University of Melbourne, ATA/Renew, and more recently the Grattan Institute) have found modern reverse-cycle air conditioners can heat your living spaces for a fraction of the cost of burning gas, LPG, or even wood.

In our Melbourne home we have been heating with our air cons for a few years now at only one-third the cost of using the old ducted gas system. That’s a 67% savings.

But who else has done this?

Quickly growing to now 30,000 members, at the social media group My Efficient Electric Home thousands of people are discovering their air cons have a role to play outside of summer. Many of our members have enjoyed substantial savings on winter heating bills.

“We used our RCAC (reverse-cycle air con) this winter in Canberra, worked great and on track to save $1100 on heating costs compared to last year on gas. Very happy.” – Jacqui 

“We only heat with our aircon through the whole winter. It’s great!” – Jessica 

“I had my gas fire uninstalled a couple of months ago. Haven’t missed it. In Canberra!” – Paul

“Used our RCAC all this winter for heating in central Vic.” – Vaughan

These personal experiences align with our 2015 University of Melbourne research where we found that big savings are possible: $658/year for a large Melbourne home or $1,733/year for a large Canberra home (see table).

Push that button

Overall, our research identified that Australian householders could save billions of dollars each year – simply by pushing a button. This is about the biggest consumer win ever, yet not enough people know about it.

In Europe, northern Asia and across North America, heating homes and other buildings with heat pumps is recognised as a key part of solving the climate crisis. In a recent report, the International Energy Agency (IEA) declared that

“High efficiency electric heat pumps become the primary technology choice for space heating in the Net-Zero-Emissions-by-2050 scenario.”

Closer to home, for many years, people in New Zealand and Tasmania have been accustomed to heating their homes with “heat pumps”, as reverse-cycle air cons are referred to there.

But back on mainland Australia, who else has worked out we are better off heating with our air cons? Here are some examples:

1).  The consumer comparison body Choice Magazine recently described the benefits of the all-electric home.

2). The Australian Capital Territory (ACT), famous for being the first Australian state or territory to reach 100% renewable electricity, has moved on to the next goal: getting homes and businesses off gas. Recognising the advantages over gas heating, the ACT offers rebates for installing air cons.

3). In a recent state budget announcement, Victoria will support the installation of 250,000 reverse-cycle air cons, replacing gas-burning and other less efficient heaters. From the Victorian government body Solar Victoria:

“with gas prices having gone up, and the efficiency of electric appliances having improved markedly and with solar PV systems more affordable than ever before, it can now be cheaper and more environmentally friendly to go off-gas and run an all-electric solar home. ”

4). AGL, who over a century ago began life as the Australia Gas Light Company and is now among other things a retailer of both electricity and gas, has begun to advise their customers that they’d be better off not buying any gas at all.

“Switching to an all-electric household could save you money and help the environment.” – AGL

As we head to net-zero greenhouse gas emissions by 2050 if not sooner, most Australian homes that need to be heated in winter will eventually enjoy the benefits of using a reverse-cycle air con.

This winter, find that “heat” button on your remote control. Whilst you are collecting renewable heat from the air outside your home, you can collect some big savings.

To come in our next Explainer: If heating my house with an air con is so great, why can’t I use the same technology to heat my water?

Tim Forcey is an energy advisor, researcher and author.

See also:

Explainer: Why hot-water heat pumps are great for homes with or without solar PV

Explainer: How electric induction cookers work and why they clear the air

Explainer: How to cut home emissions and power bills by fixing leaks and insulation