Home electrification in one chart

There are a lot of ways to transition from a fully-gasified home to an all-electric, energy-exporting home.

As recently as 2008 with regard to energy-efficiency, our more than 100 year old weatherboard home wasn’t much to brag about. 

Here is our story, illustrated in one chart. But let’s start this story even further back.

Extending a glorified tent

In 1994 when we migrated from the winter ice and cold of North America, we bought a creaky old weatherboard in Bayside Melbourne. We later had a few questions. 

When adding two bedrooms we asked: “Do we need double-glazed windows in this Melbourne climate?”

To which we heard: “Nah, you don’t need double-glazed windows!” 

Fine. 

Back then I don’t know where we would’ve found such exotic windows anyway. When I was a kid in the 1970s my folks overseas had triple-glazed windows, but if single-glazed is what we do here in Melbourne, we were happy to go along.

“Do we need insulation in the walls?” 

“Nah, you don’t need insulation in the walls.” 

In this case, this advice seemed crazy, so we lashed out and put insulation in the walls. 

“And how should we heat the place?” 

“Well, a lot of folks these days are going with ducted gas heating…” 

That was fine, because in 1994 climate change was not much on the radar and because I had migrated to Australia to work as an engineer in the oil and gas industry, I knew Victoria would enjoy cheap gas for the next 20 years.

For summer cooling, the house came with a clunky old through-the-wall cooling-only air conditioner that was already past its use-by date. But we continued to use that on super-hot days for another two decades! 

And so on.

Fast forward to 2008, as it became clear we’d be staying in this house for a while, we decided to make some comfort and energy upgrades.

The chart shows in red how in 2008 we bought 13,000 kilowatt hours of gas (equivalent to 47 gigajoules, for those that prefer gas industry units). Along with that, shown in blue, we bought 6000 kilowatt hours of electricity.

By today’s prices that would be nearly $2000 a year for energy. That ignores supply charges that add around another $600 a year for a total of $2600 a year.

So what happened next?

Six solar photo-voltaic panels – it’s a start!

Some folks will remember back in a 2007 pre-election ploy, the Howard government offered a $5000 rebate for one kilowatt (six panel) solar PV systems. Catching governments by surprise at the same time, the price of solar panels began its quick descent. We joined a neighbourhood bulk-buy program that saw us install those panels for only $499 out of pocket. Favourable state feed-in tariffs made it an even better deal, and we achieved a one-year payback! 

Even still, some of the neighbours stayed away from the bulk buy. They didn’t see the value.

As that old saying goes: “You can lead a horse to water…”

With this first small change, the chart shows that by 2009 our electricity purchases (net, imports minus exports) began to fall.

Late 2009 and again in 2012 found us renovating the front and then the back of the house, with full insulation (except for underfloor where there is inadequate clearance from the ground), double-glazed windows, good interior window treatments and draught proofing. 

But the equipment with which we heated and cooled the house remained unchanged. 

Looking at the chart, it’s hard to see the benefits of the improvements to our home’s thermal envelope (windows, insulation), because at the same time, other things would happen in and around a home. 

Older children went and then came back and then went again. Some years might see the house vacated for a mid-winter overseas trip. Some winters were colder or warmer than others. And then in more recent years, we’d see the phenomena of working from home. 

Homes are difficult places in which to perform science experiments because the variables keep changing!

The big heating switch

And now for the big space-heating switch. In 2015 at the University of Melbourne, we were starting to work out that reverse-cycle air conditioners (heat pumps) had improved so much, and gas prices had increased so much, that the point had been reached where a Melbourne house could now heat with aircons for only one third of the cost of heating with gas. This was amazing news, and we published a report.

But I couldn’t just publish a report. Being active in the climate solutions community, I also had to walk the talk. And why not save some money in our own home? And why not finally get some modern and efficient summer cooling happening?

So in went two very efficient Daikin US7 split-system reverse-cycle air conditioners: one in a main living area (TV room, eating area, kitchen), and one in the master bedroom.

The chart shows the impact where by 2017, we used only 14 per cent of the volume of gas we had consumed just two years before in 2015.

Heat pumps can heat water too

Also in 2017 we ditched the 23 year old gas hot water heater and replaced it with a heat pump. By 2018, we were using only 3 per cent of the volume of gas compared to what we used to use back at the start of the chart in 2008.

Gas goes down, electricity doesn’t go up… much

Here’s a key point. The gas industry says we can’t electrify our homes because it will crash
the electricity supply system. I debunked that last year, but what does the chart say?

Compare 2016 with 2017: gas use at our house collapsed but electricity use didn’t go up
that much. The gas industry says this impossible. So how did we do it?

People forget that ducted gas heating uses a lot of electricity – to blow air throughout the house. Instead, apply the same amount of electricity to a not-ducted reverse-cycle air conditioner and you can get quite a bit of heat while using no gas. And then as you are yet to see, with an expanded solar PV system coming along in 2018, our net electricity demand then also collapses.

The fossil gas distribution businesses are fighting for their survival as electrification proceeds, so don’t be surprised when they engage in some straw grasping.

More solar PV and kitchen renovation 

Also by 2018, I had founded and was administering the fabulously successful Facebook group My Efficient Electric Home (MEEH, now with 65,000 members), where we began to see dozens, then hundreds, and then thousands of homes fully switching their homes off gas.

So it was a little embarrassing, and I would from time to time have to endure ribbing from MEEH members reminding me of two things: 

• “Tim, your one kilowatt solar PV system is pretty small.”

• “Tim, you started this group and you are still using gas!”

So later that year we abandoned the high feed-in tariff that our six panel solar PV system was still earning when we added 22 panels more (or another 6.6 kilowatt of panel capacity).

And then nearing the end of this story, in mid 2021, our kitchen range-hood fan died. This spurred us to embark on a long-overdue kitchen renovation which brought with it a permanently installed induction cooktop. Prior to that, we were using a portable induction hot plate from time to time.

Now the house was 100 per cent off gas, fully-electrified. I rang up our gas supplier and they hauled the gas meter away.

The chart shows in 2019 the household had become a net energy exporter. Now it is 2022 and we are enjoying our first fully-electrified calendar year!

Comfortable on the cheap

For the past 12 months our total energy bill (electricity only, no gas, includes supply charges), was $526, down from where we could have been spending $2600 a year had we made no changes.

If we look at only the electricity we need for heating and cooling, we spend less than $150 a year. And we are comfortable. 

Worryingly, as a practicing home comfort and energy advisor, I know there are Victorian homes out there spending $5, $10, $15, and even $20 a day to heat with gas. They will spend as much on heating in two weeks as we will spend for an entire year.

I know every home and its occupants are different. But that’s our story.

Oh, a few more details in case you want to try to compare your home’s figures with ours. We have no electric car/vehicle yet. So though I can say that our house is electrified, our transport is not. We have, through the whole period shown on the chart, operated a luxury item: an electrically-heated spa. 

And our $499 kilowatt PV system continues to tick along in its 14th year.