Going green Home life

Greening my house, the next chapter

Not a transport post, though it does get a mention.

Previously in my quest for a greener house:

I’ve got two new house upgrades to report on.

Solar PV

This was originally meant to happen with the heat pump electric hot water: solar PV panels.

The current state government solar rebate (up to $1850) made it pretty compelling – even if the feed-in tariffs aren’t what they once were.

I got 14 panels: 6 on the front (north-facing), 8 on the back (south-facing, but tilted to be close to horizontal to pick up the sun) providing up to 4.62 kW.

Why so few mounted on the north side? Because there’s not much space up there. The western side of the roof would be the next best choice, but it gets a lot of shadow, and the eastern side probably will as well in the not-too-distant future, depending on development of the block next door.

What’s my power usage? Typically 10 to 12 kWh per day – so far the panels are generating 9 to 20 kWh per day, but it’s steadily dropping as we head into winter and there are more grey days.

Of course while the panels are generating more than I use, the only “free” power is what I use while they’re generating because I don’t have a battery. I can make use of that by using appliances such as the washing machine and dishwasher during the day.

Solar power generation

Heating and cooling

The other upgrade is I got three new reverse cycle split systems: for the two bedrooms and the kitchen.

I’d been thinking about doing this for a few years, but the impetus is that the old gas central heating broke down in spring last year. I could get it repaired but given it’s probably around 25 years old and I’d been thinking about changing over from gas to electricity anyway, it seemed like a good time to go for it. (Now I need to figure out if it can be removed from the roof.)

The older reverse cycle unit in the livingroom from 2017 is a Fujitsu. It’s been okay, but the remote control is a little fussy about receiving a signal. I’d also looked at the Choice reviews and reliability reports, and the energy efficiency scores, and this time went for Mitsubishi Heavy Industries.

(Trivia: Mitsubishi Heavy Industries is a different company from Mitsubishi Electric. They split 100 years ago.)

All the units have timers, so can be set on a program. But unlike the old central heating, you can’t easily switch them on all at once. I’m considering investing in Sensibo or similar controllers to enable unified control around the house via an app, including automatic timers, remote control and location detection (they can all switch off when nobody’s in the house).

Power consumption: Gas and electricity

Moving off gas

No surprise that my old daily average gas use has reduced markedly.

  • Was about 60 MJ in summer (cooking + hot water)
  • Was about 250 MJ in winter (cooking + hot water + heating)
  • Now less than 10 MJ (just cooking) – a huge drop

(I’ve rounded up the current figure to adjust for the reduced amount of cooking in the house now.)

To put it another way, in calendar year 2019 I used 52248 MJ of gas, which this calculator says generated 3657 Kg of GHG – roughly the same as driving 7500 Km in a petrol car. Very happy to have cut almost all of this.

Compared to winter gas bills of up to $500 in the past, my most recent gas bill was just $60 for two months: supply charge $47.62 + gas $3.10 + green gas surcharge $8.83.

I’m no doubt using more electricity – but it’s a bit hard to discern how much because 2020 brought other variables: more time at home, but then my sons moved out in August – as well as the new solar now offsetting it.

The beauty of switching is that gas is a non-renewable fossil fuel. It always will be. But electricity can be generated locally or elsewhere as renewables.

Making it affordable

The key to these changes has been doing them as various appliances needed replacement – which is why City of Yarra’s proposal to begin moving off domestic gas is important. You don’t rush it. It can be a long process.

Can I also change cooking to electric and get rid of my gas connection completely? Perhaps – my kitchen is overdue for renovation – and the reports of the health risks of gas cooking are notable.

I also have a barbecue using portable gas bottles.

Overall, cooking is a small proportion of the gas usage in most households. (In my house, even with my low level of driving, I would assume the car is now my top emitter.)

The Victorian Opposition has taken a somewhat ridiculous stance on the transition off domestic gas. Presumably channelling the NRA was an attempt at humour.

I think some people forget that the heavy use of natural gas in Australia is actually unique to Victoria.

Natural gas has burnt in Victorian homes for decades, not just for cooking but for hot water and heating too. With up to 3 million connections and 65 per cent of the nation’s total residential use, Victoria is unique in Australia for its reliance on gas as a fuel source.

The Age 9/5/2021: How Victoria got hooked on gas, and why the heat’s on to find new fuel

There is an opportunity here to start moving households to electricity with domestic solar power. It cuts emissions and reduces running costs, helping household budgets.

But rather than obsessing on cooking, based on actual usage the first priorities for existing homes should be heating and hot water. (Even the Opposition would concede that nobody cares how water is heated, as long as it’s reliable.)

I’m lucky enough to be able to push along the switch in my house. Hopefully governments can do more to help others make the transition too.

By Daniel Bowen

Transport blogger / campaigner and spokesperson for the Public Transport Users Association / professional geek.
Bunurong land, Melbourne, Australia.
Opinions on this blog are all mine.

12 replies on “Greening my house, the next chapter”

“my most recent gas bill was just $60 for two months: supply charge $47.62 + gas $3.10 + green gas surcharge $8.83”

So your fees are 95% of your gas bill ($340 extrapolated out over the year), might be worth looking into electric cooking?

@John S, yes, definitely considering that given I see a kitchen renovation in my not-too-distant future! Induction cooking looks pretty neat.

A gas connection for just cooking (I’d assume hotplates only, not many people have gas ovens) is overkill. Even without renovating the entire kitchen you could consider moving to bottled gas for the stove. It uses only a couple of bottles a year for a typical house. If you do have a gas oven too you’ll find replacing it is a no brainer, food cooks far more evenly in an electric oven. Don’t need to renovate the enitre kitchen to replace one appliance.

@Stirling – switching existing natural gas appliances to bottled gas is possible, but you need a gasfitter to do it – they need to install the pipes to the bottle, change over all of the gas jets to suit LPG, then adjust the pressure.

When I bought my gas stove a few years ago it came with the parts required, but for an existing stove already installed you’re probably better off just buying a new electric appliance instead.

@Marcus Good point. I’d actually been considering going the opposite way. My house doesn’t have a gas connection but our electric hotplates are terrible. It takes 18 minutes to boil 2 litres of water and then once you add the pasta it doesn’t return to the boil for another 10. Let alone trying to do a stirfry or anything that requires high heat. My partner has had terrible experiences with induction in the past (plus need all new pots and pans) so I was considering adding a gas stovetop running from bottles. Obviously going to incur plumbing costs but they’d be far less than connecting the supply from the street or paying ~$250-300 per year in supply charge for a small appliance.

@Daniel Ah, yes with a stove like that I’d probably be looking at a renovation too. Doesn’t look like there’s the standard 600mm gap to put a new appliance in anyway.

@Stirling. “It takes 18 minutes to boil 2 litres of water”
Uber Eats never looked so good!

For those having difficulty cooking with electricity and wondering how to use gas just for their cooking, may I recommend a gas barbecue. While our house does have mains gas and a gas cooktop, we use the side burner on our new BBQ when we want serious heat. It is more powerful than even the wok burner in the kitchen, and it could be just the ticket for people who want to have the ability to do high-power gas cooking for some tasks, but can mange other cooking with induction indoors. It also means the gas emissions are outside and can’t poison people in the house.
Without serious electrical power available, an electric stove will always struggle to boil a large quantity of water (and oil will be even harder, if you like deep-frying as I do). A proper, wired-in induction cooktop will manage it, but a single induction hob that plugs into a power point simply cannot do more than you can achieve with a kettle.

@Phiup Thanks for the useful information. I was also considering one of those singles induction hobs but you raise a great point about the power supply. Will certainly try the BBQ in the future for stirfry. Sounds like a simple solution to my immediate needs.

Yes, it’s quite funny that the government wastes money expanding the gas network when it would be cheap to supply those residents with free spli systems and heap pump hot water.

It’s worth clarifying that solar electricity is not “free” when you have a feed-in tariff. Opportunity cost means that any solar electricity you use costs you the same as the feed-in tariff, because the power is no longer available to be sold.

It may seem pedantic, but it’s useful to keep in mind when assessing the economic viability of changing appliances and tariffs.

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