As concerns over climate change grow, individuals are increasingly looking for ways to reduce their carbon footprint without breaking the bank. Enter the era of hybrid home heating.
By Tony Pan
In 2000, the market for gas-electric hybrid vehicles in the U.S. was in its infancy, with fewer than 10,000 hybrid car sales. In 2020, this number was over 500,000; adoption has skyrocketed. On average, a hybrid car emits about 50% less greenhouse gas emissions than an internal combustion engine vehicle.
For the many Americans who can’t afford an all-electric car, driving hybrid cars has helped them make a huge sustainability impact and also save money – less fuel used and less wear on brakes equals lower operating costs. Electric cars are indeed the most sustainable and climate-friendly vehicle option, on average reducing 7,661 pounds of CO2 annually compared to a gasoline car — but, the humble hybrid car realizes 70% of that reduction. So, while there’s a lot of talk about “electrifying everything,” given the high cost and long timeline of full electrification, we also need to adopt the hybrid approach to decarbonizing other products and systems to make significant impacts as quickly as possible.
Heating and cooling for buildings is one of those key systems, comprising about 50% of home energy demand in the U.S. and a whopping 80% in Europe. Electric heat pumps, the gold standard for HVAC in a new eco-friendly home (if paired with renewables), are not currently taking off at full speed because they are expensive. Generally, electric heat pumps pay for themselves quickly when they’re built into a new home with no retrofit cost, when they’re used in southern regions of the country to provide both cooling and heating, or when they’re replacing an oil furnace. However, in many other parts of the U.S. it does not make economic sense to replace a natural gas-powered system with a heat pump. Over 50% of U.S. homes — about 60 million total — use natural gas for heating. Where and when is the highest consumption of that gas? Unsurprisingly it is in the northern, colder states, where heat pumps are less efficient and more costly to operate. And most of that gas for heat is needed during nights and winters, when we lack solar power to fully realize the sustainability benefit of electric heat pumps.
While we should fully electrify as many cars and heaters as we can and connect them to renewable energy sources, what can we do about the rest? Similar to the hybrid car, we can deploy hybrid solutions for home heating, too. First, there is the simple ‘hybrid’ of having both a heat pump and a gas furnace, respectively covering mild and cold days, but that requires doubling up on equipment and upfront investment. Hybrid furnaces — or hybrid boilers for steam radiator systems — are a relatively new option that provide the electric-gas hybrid benefits in a single piece of equipment. A gas-fueled furnace works by burning fuel to produce heat, and then distributing the heat throughout a building. But conventional furnaces are incredibly wasteful because they let their high-grade heat degrade and cool down before that energy is used; this squanders most of the useful energy content in the fuel.
Fortunately, advances in technology have made it possible to “hybridize” this process at the scale of a home appliance and generate both heat and power from fuel. This is done either by converting the high-grade heat inside furnaces into useful electricity, or by using fuel cells to directly convert the chemical energy of the fuel into heat and power. This gives homes and buildings the power to generate electricity on site, from a fuel they’re already using. Due to the low cost of natural gas, this self-generated electricity is 3 to 5 times cheaper than grid electricity. Depending on the climate, a hybrid home furnace can reduce carbon emission by about 1 ton per year. As an added benefit, in the event of a grid outage, the electricity produced can keep the heating system and other household essentials running. All this can be accomplished via a drop-in appliance that fits with the infrastructure and space of existing homes. And it will be compatible with ambitious efforts to replace fossil gas with low- or zero-carbon fuels such as renewable natural gas and hydrogen, already being piloted by major utilities in Europe.
Much like the push to make vehicles more efficient and reduce emissions that started with hybrids twenty years ago, the push for next-generation home heating is just getting started. All new homes should be built with renewable electrification in mind. But for homeowners who can’t go all-electric at any price, there are still ways to do some good for the planet while saving money. Hybrid furnaces that deliver combined heat and power should be a tool in our climate action toolbox, one that delivers cost savings and resiliency along with carbon reductions. No driver’s license needed.
About the Author
Tony Pan, CEO and Co-Founder of Modern Electron, is an inventor on 250+ patents pending in energy & climate, nanotechnology, and biomedical devices. Past experiences include: Member of Global Future Councils of the World Economic Forum, in Energy & Entrepreneurship. Pro bono consultant on global health, Bill & Melinda Gates Foundation, and Global Good Fund. Term Member, Council on Foreign Relations. National fellowships: Hertz, Soros, and National Science Foundations. Formerly with Goldman Sachs. Graduate, Stanford; Ph.D. in Physics, Harvard University. Named to Forbes 30 under 30, MIT Technology Review Innovators under 35, Business Journal 40 under 40.