Episode 3: A House of Cards
On average, we spend over 90% of our lives indoors. That’s more than most whales spend underwater over their entire life. Therefore, it comes as no surprise that we demand huge amounts of energy to heat and cool rooms, cook food, produce hot water, illuminate rooms, and power appliances.
In total, buildings use 30% of the world’s energy and spew out 9 billion tonnes of carbon dioxide every year. 3 billion tonnes are direct emissions from the burning of natural gas and traditional biomass (wood, crop waste and excrement) for heating and cooking — the rest are indirect emissions from electricity use. The vast majority of these emissions, close to 6 billion tonnes, come from homes, just like yours.
But the problem extends beyond climate change. The WHO estimates indoor air pollution (largely from the burning of biomass and natural gas in buildings) causes 3.8 million deaths per year, 6% of the global total. In low-income countries, air pollution is the number one risk factor for death.
Natural gas, often hailed for its blue flame (indicating complete clean combustion), produces harmful quantities of PM 2.5 (solid particles small enough to penetrate the lungs and travel into our bloodstream) as well as nitrogen oxides, carbon monoxide, and formaldehydes. The Environmental Protection Agency estimates homes with gas appliances have 50-400% higher nitrogen dioxide concentrations than comparable homes without. Children in homes with gas stoves are also 32% more likely to be asthmatic.
The burning of fossil fuels to produce the electricity used in buildings is even worse for air quality. The same WHO study estimates 4.2 million deaths are caused by outdoor air pollution every year. These effects are disproportionately felt by ethnic minorities and the poor in low-income countries.
There must be a better way of doing things. Not just for the long term reduction in greenhouse gas emissions, but also for the immediate health of ourselves and our children.
Thankfully, with the current rise of renewable energy, we have the opportunity to decarbonise buildings by switching to electrical appliances, which, combined with a drastic improvement in energy efficiency, will supercharge the transition to net zero and cut out harmful pollutants.
And this won’t mean we have to live a restricted life of short showers, cold winter nights and stinking hot summer days. In fact, by implementing a few easy technologies, we can clean up our buildings in a way that frees us from the guilt of energy use and saves money in the process.
But if it’s such a good deal, why aren’t we doing it? We spend far too much time bemoaning big corporations for contributing to the climate crisis, when really, there are many things we, as individuals, should be doing to help. The technologies listed in this article are all readily available and economical — there really is no excuse not to play our part in solving the climate crisis and implement them in our homes.
Heat Pumps: the future of heating and cooling
Electric heat pumps could provide the world’s entire heating and cooling needs at a drastically lower cost than conventional technologies, whilst simultaneously eliminating emissions and pollutants if powered by renewable energy.
You probably don’t know it, but you likely have heat pumps in your house right now. There’s a reason air conditioners are always half-in, half-out of buildings. They make a room cool by transferring heat from inside to outside, the result of which is a fan blowing cold air in and hot air out. Your fridge works like this as well — in fact, you may have noticed it’s quite warm standing beside it.
Now, a heat pump is the exact same thing, except this time the process is reversible. In summer, it works exactly like your fridge and the AC. In winter, it extracts even the smallest amounts of heat from the outside air, and transfers it inside. Plus, the heat doesn’t have to be sourced from the outside air — heat pumps can collect heat from geothermal resources or rivers as well.
They are also effective at boiling water for showers, baths, taps and other appliances. As space and water heating are the two biggest energy users in buildings, electric heat pumps (powered by renewable electricity) can dramatically reduce building emissions.
But the biggest advantage heat pumps have over gas isn’t actually lower emissions. Gas heaters are about 90% efficient, meaning 90% of the chemical energy contained in the gas is converted into useful heat. By contrast, heat pump efficiency is an astonishing 300-400%. Because electricity is not converted into heat, but rather used to move heat from one place to another, efficiency can go beyond 100%.
This translates into far lower power bills for users of electric heat pumps. Rewiring Australia says the average gas-heated home spends $1.98 per day on space heating and $0.66 per shower on water heating. Remarkably, with the current Australian electricity grid, a heat-pump powered house spends less than half that: $0.92 per day on space heating and $0.31 per shower on water heating. And, with rooftop solar as well as an electric heat pump, these numbers go down to $0.19 and $0.06 respectively, a mere 10% of the cost of gas-powered heating.
But, what if you didn’t have to buy a heat pump?
Another method of decarbonising space and water heating is through centralised district heating. Used in large cities like Moscow, Seoul, New York, Copenhagen, Stockholm and Tokyo (among others, many of which are in China), district heating provides a highly efficient source of heat. Tokyo’s district heating network cuts energy use and carbon dioxide emissions in half when compared to individual building heating systems.
By transitioning the centralised heating process from fossil fuels (mainly natural gas) to cleaner sources such as renewable biomass, geothermal, solar thermal and nuclear power, city planners can dramatically reduce heating emissions at a relatively low cost.
A visual representation of a district heating system. Note, it’s very easy to switch out the fuel source for a cleaner one at any point in time.
District heating is predicted to increase to 10% of global heating demand by 2050, progressively decarbonising with clean energy sources, providing a cumulative reduction of 9.4 billion tonnes of carbon dioxide. More importantly, this transition is predicted to cost less than $500 billion worldwide and will provide more than $3.5 trillion in energy cost savings through improved efficiency.
If your local or regional government proposes a district heating network, hear them out. In the long term, it’ll probably save you a lot of money.
Insulation: one of the West’s big failures
Heat always moves from warmer areas to cooler ones. If a building cannot stop heat seeping through walls, windows and roofs, the energy required to maintain an appropriate temperature multiplies. The U.S. Green Building Council says air infiltration accounts for 25-60% of home energy use. This number is particularly high partly due to poor building standards during the oil boom of the mid 1900s when oil burners, the heating method of choice at the time, were incredibly cheap. By better insulating buildings, we can reduce this wastage, and avoid significant emissions, whether they be from electricity or natural gas.
There are many ways we can do this, including installing non-conducting material such as fibreglass, cellulose, rigid polystyrene boards, wool and straw into ceilings and walls. Double-glazed glass separated by vacuums or insulating film can dramatically reduce the conduction of heat through windows. Considered the success story of energy efficiency, the Empire State Building was retrofitted in the 2000s with better insulating glass (among other things), causing a 38% reduction in the building’s energy use.
It’s important to remember: insulation doesn’t just keep the heat inside during winter, it also keeps the heat outside during summer. India is currently experiencing a horrendous spring heatwave, with temperatures reaching close to 50˚C. Poorly-insulated, western-inspired, concrete architecture has only worsened the crisis. With global warming causing more frequent heatwaves in equatorial countries like India, better insulation will be essential.
Don’t leave the lights on when you go away!
Home and city lighting used to use a lot of energy. It was such a drain on energy supply, that at the height of World War I, Daylight Saving was introduced to save coal for essential industries. Since then, lights have become drastically more efficient, and as a result, they now account for a tiny fraction of electricity use. But there is still work to do. Currently, half of the global lightbulb sales are incandescent, halogen or fluorescent bulbs — all of which have efficacies (light per unit of energy) of less than 60 lumens per watt. The efficacies of LEDs are well over 100 lm/W.
The International Energy Agency (IEA)’s net-zero pathway has LEDs being 100% of lighting sales by 2025. We are well on track to meet that — the share of LED sales was only 1% back in 2010.
If your house is lit by anything other than LEDs, go buy some LED replacements. In almost all cases, it’ll just be a case of screwing the new bulb in.
What can AI and Machine Learning bring to the table?
Building Automation Systems (BAS) have a massive effect on energy efficiency. Using motion sensors, they can switch lights off when occupants leave the buildings and dim windows (much like Boeing 787 Dreamliners) to prevent overheating during the day. Currently installed in 34% of commercial buildings, BAS systems are tipped to be in 50% of commercial buildings by 2050. A transition of that pace is predicted to save building owners 10x the initial cost of the systems.
Thermostats control 9% of US energy consumption. Smart thermostats, powered by machine learning algorithms and sensors, can learn your routine, habits and preferences, whilst nudging you towards more efficient energy practices. They can also enact demand response techniques: using energy when there is an oversupply of variable renewables and refraining from doing so during periods of peak demand, all in exchange for cash from the energy retailer. Smart thermostats are currently installed in less than 1% of households with internet access. If that increases to 50% by 2050, we will have reduced carbon dioxide emissions by 2.6 billion tonnes and saved homeowners more than $600 billion worldwide.
The Google Nest, created by a bunch of ex-Apple engineers, is a fantastic product on the market now. Check it out, it may be a great investment.
Harnessing the sun from your own roof
With the war in Ukraine and COVID-19 related supply chain issues causing surging coal and gas prices around the world, the ability to generate cheap solar power onsite is now more valuable than ever. Because rooftop solar is at such a small scale, installation represents a significant proportion of the total cost, meaning it is overall far more expensive per megawatt-hour than solar farms. However, because rooftop solar bypasses transmission lines and the mark-up of energy retailers, it is actually significantly cheaper than grid-supplied electricity in most parts of the world. In Australia, the cost savings are so large, around 30% of homes have rooftop solar.
Combined with an electrified house, it is the surest way to reduce your personal carbon footprint.
But rooftop solar arguably has an even more impactful use: in low-income countries without an extensive electricity grid, rooftop solar provides clean, affordable electricity to regional homes and businesses, making it a powerful method of reducing poverty. In Bangladesh, close to 4 million rooftop solar systems have been installed, creating more than 100,000 jobs.
Solar Thermal Hot Water (SHW), different to solar photovoltaic solar panels, can provide efficient and renewable hot water to houses. Israel and Cyprus have mandated all houses have SHW since the 1980s. Globally, these systems account for 15% of the heating market worldwide. According to the IEA’s net-zero pathway, that share will need to increase to 31% by 2030.
If heat pumps aren’t your best option for water heating, solar thermal probably is.
Cooking with Faraday’s Law
Electromagnetic induction (changing magnetic fields inducing an electric current in certain metals) was discovered by British scientist Michael Faraday back in 1832. Little did he know, this discovery would be vital in decarbonising and improving cooking.
As per Faraday’s discovery, induction stoves produce an oscillating magnetic field, inducing an electric current in your iron or steel pots and pans, heating them up. These electrical induction stoves are far safer, more efficient, and more effective than gas alternatives, plus they don’t emit carbon dioxide and other harmful pollutants.
But in low-income countries, many people don’t have access to either natural gas nor electricity, and therefore often use solid fuels biomass like wood to cook food — the IEA says this number is as big as 2.3 billion people. The World Bank has found:
“Residential solid fuel burning accounts for up to 58 percent of global black carbon emissions and a gigaton of carbon dioxide per year—approximately 2 percent of global emissions”
The world needs sustainable biofuels to replace solid biomass in these developing nations. This will take huge cooperation from governments, international organisations, and consumers.
So, what does this mean for us?
The big problem with all of these technologies is their up-front cost: a significant barrier, especially for lower-income households and poorer nations. But they’re still fantastic investments. In fact, the cost savings of heat pumps, LED lights, rooftop solar and solar heating mean you’ll make your money back in as short as a few years, after which you’ll start saving money.
Banks and suppliers need to do their bit in breaking down this barrier to entry by offering cheap financing, just like they do with rooftop solar. Governments should require new buildings meet strict emissions requirements. In New York and Los Angeles, gas heating is now banned in new buildings. Other jurisdictions should follow their lead.
If financially able households (trust me, that’s almost certainly you) and building managers purchase these cleaner technologies, not only will they reap the benefits of massive cost savings, but they will also support the market to achieve the scale needed for prices to go down such that poorer consumers can reap those same benefits too.
We need to take responsibility for our own carbon footprint. I agree natural gas companies are causing irreversible damage to the world. But if you’re sitting in a house with gas heating, gas water heating, a gas stove and a gas oven, do you really have the right to deflect blame onto them?
In light of that, go search “heat pumps near me” on google and visit a store. Talk to your parents, your partner, your landlord or your housemates about the options laid out in this article. Be proactive about reducing your home’s carbon emissions. Not only will you save a lot of money, but you will have done your bit to prevent a climate crisis, and improve the air you and your family breathe as well.
Just like renewables, cleaning up buildings is the low-hanging fruit of the net-zero transition. But this time, it’s on you to make the change.
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