Home ventilation dilemmas in the era of COVID, climate change and renewable energy

We’ve long been advised to “seal up” or “draught-proof” our homes – to save energy, exclude allergens, and more recently to keep out bushfire smoke. Now, health authorities tell us to “ventilate”, to reduce the risk of COVID-19 transmission.

Anyone confused? And what about electricity use if we cool (or heat) the home with open windows and doors?

Unwanted home ventilation

Australia’s houses are typically draughty. There are gaps around doors and windows, and unused chimneys suck heat out of the room in winter. Downlights and exhaust fans let undesirably cold or hot air straight into our homes – regardless of how much insulation was installed.

Our historical lack of attention to building energy-efficient, well-sealed homes is rooted in Australia’s past abundance of cheap, fossil-fuelled energy. Ramping up the heating or installing an air conditioner for summer trumped building and renovating better.

While people affected by thunderstorm asthma and other allergies are often familiar with the benefits of keeping outdoor air out of the home, the overall case for minimising home air leakage strengthened as energy price and carbon emissions concerns increased.

Then, the 2019-20 bushfire crisis showed us just how little control we had over the flow of air into and out of our homes. We were told to stay indoors, close windows and doors, and only use air conditioning that recirculates indoor air. People with respiratory conditions still felt the health impacts as smoke seeped in through the gaps and cracks.

The science of climate change tells us to expect more bushfire smoke and thunderstorm asthma conditions in the future.

New pandemic ventilation needs

Health authorities such as the US Environmental Protection Authority, Centers for Disease Control and NSW government now advise keeping windows open to reduce the risk of airborne COVID transmission.

Opening up will let hot summer and cold winter air into our homes, and undo much of the benefit of home insulation. Air conditioners will have to work even harder this summer, further increasing home energy use at a time when 40% of households have already noticed an uptick in heating and cooling use since the pandemic.

There’s a massive gap between energy advice and health advice, and even the health authorities don’t seem to grapple with the contradictions of closing up to keep out allergens and smoke, and opening up to let out COVID-19 out. A pandemic and bushfire crisis double-whammy is possible this summer or beyond.

The rise of air purifiers

Air quality is a growing concern for Australian households. In response to bushfire crises in Australia and around the world, air purifiers with HEPA filters were recommended to filter smoke from the home. Air purifiers sold out, even as some health authorities remained sceptical about their effectiveness.

Health authorities have started recommending air purifiers to reduce COVID-19 transmission, and the Victorian government has publicly endorsed air purifiers via the rollout to improve ventilation and COVID safety in schools.

The recent Energy Consumers Behaviour Survey found that 11% of households across Australia already had one or more air purifier or dehumidifier, but ownership was higher in places that were inundated by bushfire for an extended period, such as the ACT (23%).

Many households are on the cusp of adopting air purifiers, uncertain which devices really work, or waiting to see if bushfire smoke inundation of densely populated areas was a “one off”.

Unprecedented bushfire crises in the recent northern hemisphere summer indicate we’re likely to see more bushfires, health impacts and normalisation of home air purification in Australia.

Emerging ‘healthy air’ trends, electricity use, and clean energy

The Digital Energy Futures project at Monash University looks at how emerging lifestyle and technology trends might impact electricity demand.

For planning a future clean electricity system that can meet the highs and lows of consumer electricity demand, these new air quality trends are quite sudden.

About 80% of homes in Australia now have air conditioning, and the electricity grid can struggle to cope with sudden spikes in demand for electricity during hot weather. “Rolling blackouts” – essentially switching off electricity supply in some areas – are occasionally used to stabilise the grid, especially during heatwaves. Using more air conditioners and air purifiers in more homes, more often increases the likelihood of power outages in hot weather.

People often think that generating more power is the obvious solution. But more power doesn’t help if the local electricity infrastructure can’t distribute it to where it’s needed, and that power comes from fossil fuels that contribute to climate change.

Inevitably, ever-higher spikes in demand increase the cost of electricity all year round as electricity infrastructure is upgraded to cope. This means higher electricity bills even for households that can’t afford air conditioning, or renters who can’t get air conditioning in the homes.

Essentially, uncomfortably hot people in non-air-conditioned homes end up subsidising more thermally and financially comfortable households.

Increasing solar electricity – both from home rooftops and solar farms – helps to some extent. There’s still a short “peak demand” problem after sunset in solar generation when households are still busy cooling, cooking, working and relaxing. This period still mostly relies on fossil fuel-generated electricity.

More battery storage can help cover this period with renewably generated electricity, as can easing off on non-essential electricity use for this one to two-hour period around sunset.

Cooling and cleaning the air in our homes earlier in the day or later in the evening, instead of right around sunset, could reduce the costs and carbon emissions of our electricity use.

Do we trust the electricity sector enough to help?

We can expect to see incentives and appeals from the electricity sector to shift the timing of some of our home activities. Networks with high solar generation, such as South Australia, are now grappling with what to do with grid-destabilising surplus electricity from solar in the middle of the day.

Switching off solar panels bumps against household investments and commitments to generate clean energy. Activities that act as a “solar sponge” to soak up surplus clean energy can help balance electricity supply and demand.

In addition to cooling and air purification, daytime heating of hot water and charging of electric vehicles will help the path to an affordable and clean electricity system.

We’ll also be asked if our home or electric car batteries can be used to put energy into stabilising the grid when demand exceeds supply, and whether we’re willing to let some of our appliances be automatically powered down at these critical times.

Read more: The climate crisis and the electricity grid: AI to the rescue

Being a bit flexible in our energy use and storage is a more cost-efficient and carbon-efficient approach – for the system and our energy use.

It’s a big ask though, given the way most people feel about electricity companies. Trust is low. Our disjointed, semi-privatised electricity sector has delivered rapid price rises, poor and conflicting communication, and variable reliability.

On top of that, households are juggling new concerns, including COVID, allergen and bushfire smoke health advice about the need for home ventilation or air purification.

All of the sector cogs – the retailers, networks, regulators, grid operators and governments that shape electricity policy – will need to work hard to gain our trust to assist them as they seek to deliver the future, clean energy-powered energy system.