It was a long, blistering summer, but many of us will soon be turning the heat back on. That means a lot of greenhouse gas emissions.
In the United States, heating homes and businesses produces about 560 million tons of carbon dioxide per year, or about a 10th of the country's emissions. But there's something that might drastically cut down on both your heating bills and your carbon footprint, no matter where you live: a heat pump.
A heat pump is an all-in-one heating and cooling unit. There are a few different kinds, but the most common ones extract warmth from the air. Then, they move it inside (to heat the home) or outside (for cooling). That requires a lot less energy than traditional heating systems — like boilers, furnaces and electric radiators — that work by warming up the air inside your house.
"There's a fair amount of heat even in the cold air," said Vijay Modi, a professor of mechanical engineering at Columbia University. He estimated that a home heat pump could cut electricity use by as much as two-thirds compared with more traditional heating systems.
The Northeast Energy Efficiency Partnerships, a nonprofit group focused on energy efficiency, found that replacing a traditional indoor heating system with a heat pump could save as much as $948 a year.
But switching to a heat pump also requires a significant investment, often thousands of dollars. That's why Dr. Modi recommended making the switch when it's time to replace to your old heating and air-conditioning system.
Much of that upfront investment will be installation costs, but many states offer rebates to help offset that expense. The Database of State Incentives for Renewables and Efficiency is one place to search for programs in your area. Manufacturers and local contractors should be good sources of up-to-date information as well.
It's also possible to get a heat pump in an apartment or in just a few rooms of your house, even if your place doesn't have air ducts. In that case, you could go with window-mounted units or, more likely, a split-unit system, where the heat pump compressor is mounted on your roof or balcony, with lines that run heat into the house.
It's worth noting, however, that heat pumps become less efficient as the temperature drops.
"In extremely cold temperatures they will not operate as efficiently," said Eileen Wysocki, an administrator at Holy Cross Energy, a rural electric utility in Colorado. She said heat pumps optimized for cold climates normally operate at 100 percent efficiency all the way down to 0 degrees Fahrenheit, or minus 18 Celsius, and at 80 percent efficiency down to minus 13 Fahrenheit. They generally shut down when the mercury sinks to minus 18 Fahrenheit.
So, if you live in a place that frequently experiences deep freezes, you'll probably want to keep a traditional heating system in place alongside your heat pump.
The precise gains from a heat pump will depend on a variety of factors like your insulation, your electricity source and local energy rates. But, Dr. Modi said, the share of people installing them is rising quickly.
"To me, it's a no-brainer," he said.
Transportation is the largest source of planet-warming greenhouse gases in the United States today, and the bulk of those emissions comes from our cars and trucks.
Last week, we published a detailed map of driving-related emissions, showing the otherwise invisible trails of carbon dioxide along America's roads. The project, based on new data from Boston University, allows you to see carbon dioxide emissions from passenger and freight traffic across the country and in your own area.
Nationally, driving-related emissions have been on the rise in recent years, despite federal and state efforts to bring them down. Boston University's data reveals that much of that growth has occurred in and around America's cities.
Using the university's local estimates, we identified the 100 metropolitan areas with the highest total emissions from driving and found that CO₂ is increasing both in total and per person in nearly every metro region. (Even the denser areas with big public transit networks, like New York City, have seen automotive emissions per resident tick up in recent years.)
But here's a bit of good news: More and more cities are looking to drive down these stubborn emissions as part of broader local efforts to avert the worst effects of climate change. And, our project was picked up by local news outlets around the country, including in Dallas, Des Moines, Boston, Tampa and Seattle. So, while emissions are rising, at least we know awareness is growing, too.
You can explore the interactive feature here.
We got tons of email in response to our item last week about children and climate anxiety. One of the most thoughtful messages was from Nirali Shah of Redmond, Wash. She had additional suggestions about kids and climate change. Here they are, lightly edited and condensed for space:
Start young — If you talk about sustainable living early, it becomes a part of how children live. That eliminates the need for behavioral changes. With smaller children, you don't need to explain why the environment is important.
Connect with nature — Help your kids develop an emotional connection with nature at a young age. Talk about local plants and animals. We hear about the importance of having children empathize with other people, but extend that to nature by taking care of plants, discussing how animals live and picking up litter. If they have that connection, they're more likely to become the environmental stewards of tomorrow.
Talk about science — Show your own respect for science. Read and discuss space, explorers, weather and more. Encourage young people to ask questions and look up information together. Talk about how to identify valid sources.
Thanks, Nirali! And have a great week.
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