How the Unassuming Heat Pump Can Stave Off Warming

California’s latest climate plan includes a goal to deploy 6 million heat pumps by the end of the decade — and with good reason. These unassuming boxes are at least twice as efficient as gas furnaces by conservative estimates, and can significantly cut down the carbon a home or commercial emits.

California’s Public Utilities Commission estimates that 12% of the state’s greenhouse gas pollution comes directly from commercial and residential buildings — that means gasses wafting from rooftop vents, or indoor stoves. That percentage is roughly the same for the U.S., and the majority of those emissions come from the heating and cooling of buildings. Considering shrinking the climate footprint of your home by swapping large gas guzzlers like your furnace for the humble and efficient heat pump? Read on.

What is a heat pump?

A heat pump can warm or cool a home, working by capturing heat and moving it from one place to another. If you’re heating your home, the heat pump will absorb heat from outside (either from the air or the ground, depending on the model) and transfer it indoors. If you’re cooling your home, a heat pump does the opposite, absorbing heat from inside and moving it outdoors.

“Heat pump technology has actually been around for many decades,” said Alejandra Mejia Cunningham, a building decarbonization advocate with the Natural Resources Defense Council.

It’s likely you already have a heat pump in your home, in the form of a refrigerator. That system absorbs heat swirling around your food and moves it outside — where you can feel it escaping from either behind or under your fridge.

A furnace, on the other hand, generates heat by burning natural gas or other fossil fuels, warming the air around it, like a bonfire.

Heat pumps are used both for space heating, to warm and cool the air in homes, and water heating. In this article, we’re largely discussing heat pumps that warm and cool the air.

What are the benefits of a heat pump?

Efficiency. Heat pumps are at least twice as efficient as gas furnaces, and frequently cited as far more efficient than that estimate. Engineer Sam Calisch of Rewiring America says the technology is improving rapidly.

Emissions. Residential heat pumps can cut a home’s carbon pollution by 40%–50% compared to gas furnaces, according to a study from researchers at UC Davis. And as California’s grid relies more on solar and wind, “the carbon footprint of your home will continue to fall over time,” said Mejia Cunningham.

Daniel Hamilton, sustainability and resilience director for the City of Oakland, estimates that “if all of the homes in Oakland were to switch to heat pump space heaters, it would eliminate half of the greenhouse gas emissions from the residential sector.”

What are the drawbacks of a heat pump?

In cold climates, heat pumps “are simply less efficient than they would be in a warmer climate,” said Duncan Callaway, associate professor of energy and resources at UC Berkeley. And heat pumps may not be able to adequately heat a home in places that get into double-negative digits.

“I’m thinking about places like the upper Midwest or Alaska, places that are quite cold in the wintertime,” Callaway said.

Researchers at the University of Texas, Austin analyzed residential heat pump adoption looking at a variety of factors, including energy prices, carbon emissions, health effects from emissions and demands on the electricity grid. The results showed that 32% of U.S. houses would benefit financially from installing a heat pump, and 70% could reduce emissions by installing a heat pump.

Researchers found that heat pumps are a powerful decarbonization tool in California and other places with mild climates, but aren’t the best financial option in colder climates. In a small minority of places, heat pumps can actually produce more emissions.

How much do they cost?

Heat pumps can be expensive upfront, but there are several state and federal programs to help defray the cost.

“Heat pumps come in all shapes and sizes, from window units that can be several hundred dollars to full central air-conditioning systems that cost $20,000 and more,” said Joel Rosenberg of Rewiring America.

The cost of a project ranges based on home size, the type of heat pump and whether other aspects of the electrical system need upgrading, such as the electrical panel.

In Oakland, heat pumps can set you back $15,000 to $20,000 dollars, but Hamilton, the city’s sustainability director, emphasizes the available discounts.

“Moderate-income residents can expect to get about a third of that cost covered by rebates and incentives, while lower-income residents can get about two-thirds of that covered,” he said.

How can I get incentives and rebates?

Californians can check the average costs of recently completed projects in their county by reviewing data gathered by the statewide incentive program TECH Clean California.

The heat-pump-curious can search for statewide incentives they may qualify for through The Switch Is On, a campaign led by the nonprofit Building Decarbonization Coalition. Rewiring America has a helpful cost-savings calculator to assist in navigating the money available through the Inflation Reduction Act, major federal legislation passed last year.

If you’re in the market for an air-conditioning unit and a new space heater, a heat pump does both, and will be less expensive than buying both.

Will monthly bills decrease?

This depends on many factors, such as the price of gas and electricity in your area, and how much you use your heat pump.

Rosenberg of Rewiring America said that for many, monthly bills go down. “Electrifying space and water heating would reduce energy bills for 12.9 million households in California across every county and fuel type, saving $414 per year on average,” he said.

Mark Hall, founder of energy-efficiency company Revalue.io in Oakland, said his customers see their bills decrease by roughly 40% after installing a heat pump, which he typically pairs with adding insulation to homes and sealing leaks in homes where outside air may come through.

When should I make the switch?

One of the challenges people encounter when making the swap to a heat pump is getting caught off guard. If a gas furnace goes kaput on a cold night, many will choose the contractor who can get a new appliance installed as soon as possible. And that person may not be able to install a heat pump in the time frame they want.

There is a shortage of electricians, technicians and other contractors, making it challenging to find companies that can squeeze you into their schedule. So, to electrify, Rewiring America’s Joel Rosenberg said, you need a plan.

“If you think you’re going to want to replace your furnace with a heat pump, it makes sense to start calling contractors, getting quotes and putting your ducks in a row,” Rosenberg said. He even wrote a how-to guide (PDF) for people making this kind of plan.

You’ll also be able to get a sense of cost and savings, too. Many of the federal incentives will likely go into effect in late 2023, so some people may want to wait for that.

Cheryl Ajirotutu recently installed a heat pump in her Oakland home, which she said increases her quality of life and saves her money. But beyond that, she is excited to take action on climate change in her hometown.

“We have a diverse community. We have an incredible housing stock. So there’s a great opportunity here to do these kinds of things and to show that it works,” she said.