Electrify me (a little less) - Part 2

The key to a lower carbon emissions household? Energy efficiency and renewable generation

Going back to our greenhouse gas emissions baseline, our top 3 household emissions came from food🍗, transport🚗 and then household energy use🔌. For the average household though, its energy, energy, energy, at around 65% of total household emissions.

I am not sure what this says about how frugal I am on the heating and cooling or about our food bills🤷‍♀️?

After dabbling in sustainable choices late last year, we made our first round of long-term changes in January, introducing food swaps and composting. I got seriously excited when my first bucket of homemade soil goodness was ready to go!!! For all you other composters out there, the eggshells though!?

I decided not to tackle transport until June. A few reasonable but slightly avoidant reasons for waiting until then -

1. I know its going to be super hard to change up our day-to-day car rides just now, with kids too young for the bus, and,

2. because I've just started a new job, I'm tempering the spending until I've settled in as I suspect the only way we can get serious about cutting emissions here will be an electric vehicle.

So yep, our March theme is tackling energy usage. I got a big headstart on this theme back before Christmas when I installed solar panels. I also wrote about the impact heating and cooling has on our electricity usage in my post Electrify me (a little less) - Part 1.

Since then, I've tracked down some average electricity consumption by category for Western Australians. It's not too dissimilar to the Australian averages, with heating and cooling by far the biggest category followed by water heating (for dishwashers, showering and washing machines).

Breakdown of average electricity consumption by category, WA

"According to the Australian Government's Department of Industry, Science, Energy and Resources, in 2018-19, the average Australian household's direct emissions from energy use* were around 7.6 tonnes of carbon dioxide equivalent per year. This accounted for around 65% of the average household's total emissions."

*This energy use is more than electricity, it includes energy in all forms - gas, fuel use in lawnmowers, combusting wood for fires and more.

We've talked before in Part 1 on tips to cut down electricity for cooling, but let's recap then get to heating:

1. Manage your cooling in summer:

• Set the reverse cycle air-con to 25-27degrees celsius in the heart of summer, each degree of extra cooling will increase energy consumption by ¬5-10%.

• Aim to keep the house at a steady temp all day by starting the aircon earlier in the day before the house heats up (start earlier, keep it around 25-27deg C.).

• Don't have aircon? Same principle applies, to prevent the house from heating up invest in some good block-out curtains and keep the heat out.

• Finally - as soon as you feel that breeze, release the dungeon vibes, open up the curtains and windows and cool the place down for the evening, prepared to do it all again the next day.

• If its not too warm then don't put the aircon on, seems pretty simple but its amazing how many people get use to the temperature being steady and use their aircon too long past the heart of summer. Other low to no cost things you can do before you turn the aircon on include: put on a singlet, take off your shoes, have an iced water, sit in the shade, open the windows for a breeze, add tall plants near windows to shade rooms, or install some awnings (you can get relatively cheap ones from Bunnings).

• I had the magical AI run me some numbers comparing the energy saving and carbon emissions saving you would get from running a reverse cycle aircon at 22 degrees compared to 27 degrees over the mid December to mid-March period in Perth. It thinks you would save around 0.1 to 0.2tCO2e for the summer, which is a decent emission saving from dealing with slightly warmer weather. I also acknowledge our privilege in that there is no-one in our household that would have any adverse impacts to their health from dealing with the heat.

2. Manage your heating in winter:

• Tricky one for me, because we don't actually use the heater a lot in winter. Thats probably a habit born out of not having any installed ducted heating (our aircon is evaporative). If there's a cold snap or for about a month of the year to warm up the air in the morning and evening in our family / kitchen room, we use a Dyson Hot & Cool reverse fan. Other than that, we are serious dressing gown people from late June through to August or early September. House socks, slippers, oversized jumpers, throw rugs on the couches and dressing gowns keep us warm!!

• If we want to talk heating more generally though, here's the lowdown -

1. (New addition) Heat pumps: Heat pumps are the most energy-efficient way to heat a home (just not yet very common in WA). They work by extracting heat from the air or ground and using it to warm the home. They can be up to three times more energy-efficient than conventional electric heaters.

2. Reverse cycle air conditioners: are generally the most energy efficient choice - but follow some of the similar guidance for cooling above. Keep to a steady temperature of around 18-20 degrees Celsius when warming the house (same logic still applies, every additional degree will increase energy consumption by around 10%). For heating, also watch for drafts that will let the warm air out.

3. Gas heaters: Although gas heaters are efficient at heating your home, they emit carbon dioxide when burned. Natural gas produces around 55kg of CO2 per gigajoule (GJ) of energy consumed, while LPG produces around 63kg of CO2 per GJ. Do not recommend for emissions saving!

4. Wood heaters can be quite efficient if you have access to free or cheap firewood. However, wood heaters are quite polluting and can release particulate matter or carbon monoxide if not properly ventilated in indoor areas.

5. Electric heaters: Electric heaters can be energy efficient, but generally less than the old reverse cycle. These can be good for only heating up one space (like our family room) and it's good to make sure its set to a reasonable temp on its thermostat similar to what you would do in point 1 (i.e. keep it set at around 20 degrees).

6. Portable heaters: Other portable heaters are generally less energy-efficient than the other options, and they also emit carbon dioxide when using electricity or burning fuel (depending on what they are).

It's worth noting that there are ways to reduce the carbon footprint of any heating option, such as using renewable energy sources like solar or wind power to generate electricity or using natural gas sourced from renewable sources like biogas. Improving the insulation in your home and reducing heat loss can help reduce the amount of energy required to heat your home, regardless of the heating source you use. And like we do, just put on a dressing gown and socks! I totally get this is a Perth winter solution as we are rarely getting below an average low of 9 degrees celsius in Winter.

3. Manage your water heating:

• The biggest water heating saving for many of us is actually from dishwasher use. I have a Bosch series 6 dishwasher (4 star energy rating and 5 star water rating) and if I run it every 2nd day for a year on the eco cycle (45deg) versus the max cycle (65-75deg) then it will save around 0.13tCO2e a year which is not bad for just changing the habit of which button to press. They run for around the same time and I haven't noticed a difference in cleaning quality. I also try and wait until its pretty full before turning on and add lunchbox containers and the like after discovering that it was more energy efficient to fully utilise the dishwasher than to handwash.

• There's a lot of studies out there comparing handwashing to dishwashers and finding that dishwashers can generate half the emissions and water use of handwashing. However, it does require a few things to be true - you're using an energy efficient dishwasher, you scrape plates (don't rinse - you don't need to!) and wait until it's pretty full before using. If you haven't got a dishwasher, then again scraping not rinsing, and not leaving the tap running can save the energy and water use.

• I can't believe I am writing this - but obviously shorter showers ok? Winter is coming and I will be aiming to set the timer and encourage better habits here. However, don't get too excited - its great to save the water, but the carbon emission savings from halving your shower time from say 8 minutes to 4 minutes, across three of us in the household would save only about 20kg CO2e a year. Again, you can save that by simply changing one family meal that was red meat based to chicken or plant-based and get the same saving.

• Wash your laundry in cold water (ok it's going to save you maybe $10 a year to swap from warm to cold and save emissions equivalent to eating one less family dinner of spaghetti bolognaise in the whole year - but still, its an easy change to make).

The key to the biggest saving on carbon or carbon equivalent emissions for households is going to come from -

1. Managing or lowering your energy use overall, and

2. Using renewable sources of energy generation and storage (let's talk storage another time).