There’s a good reason why the federal government is giving $450 million to New England to help get electric heat pumps into homes and businesses: They’re great machines and not just for climate change reasons.

“I have been saving about $1,000 a year,” said Natch Greyes, who lives on Broad Cove Drive in Concord. Three years ago he and wife Therese replaced hot-water propane baseboard heat with electric heat pump mini-splits in their 20-year-old house, a move that gave him complete air conditioning for the first time.

They are saving money partly because these devices, which move heat rather than just create it, are extremely efficient: “I have a whole-house air conditioner for basically the same energy use as a bedroom AC.”

Saving money is good. So is being comfortable as our summers get toastier and winter weather gets more erratic.

 “We have two kids (ages 8 and 11). It’s nice to have a temperature where they can sleep, that’s a big difference,” said Oscar Gala Grano, who bought an 1890s home on Appleton Street in Concord in 2021 and changed the oil-fired boiler for a forced-air heat pump system.

These two folks were among a number of people who responded to my online request for experience with a heat pump. My query was spurred by the EPA’s $450 million grant to the New England Heat Pump Accelerator, a coalition enabling heat pump usage in our six-state region. The EPA also gave $38 million to shift homes from oil heat to electric heat pumps in southeast Alaska – yes, Alaska, for those of you who think they don’t work in the cold. Maine is also a heat pump hotbed, so to speak.

Electric heat pumps use the magic of phase-change physics to move heat from outdoors to indoors in winter and vice-versa in summer, which turns out to be a very efficient way of changing the temperature inside a building. The technology has improved enormously in recent years; I had a heat pump in the 1990s and it was crummy.

Electric heat pumps are one of the key devices we need to adopt to reduce our effect on global warming. At the very least, new housing or apartment construction should always have heat pumps.

Despite my physics metaphor, however, heat pumps are not actually magic (nothing is, sorry Hermione). So even as I celebrate this technology – I’m getting bids for replacing my home’s oil furnace with it, partly because the climate is eroding my “I don’t need air conditioning!” bravado – it’s fair to point out some shortcomings that were brought up by users.

A minor one: It takes a bigger generator to start up and run a heat pump than your standard home furnace. If you lose power a lot, you’ll need to upgrade the backup. You may also need to upgrade your home’s electric panel.

A less minor one: You probably can’t swap out an existing forced-hot-air boiler for a heat pump because the requirements for ductwork change. Many people need to put separate mini-splits in various rooms, all powered by an outdoor heat pump or two, which creates lots of decision-making.

“I ended up getting three different bids and every installer recommended putting them in different places,” said Greyes.

An even less minor shortcoming: The heating is different than that provided by machines which burn fossil fuels. Usually, this doesn’t matter but there are times when “different” means “not as good.” (They cool exactly as well as a standard air conditioner.)

Several comments noted that their heat pump doesn’t ramp up heating as quickly as oil or propane furnaces, and there are times in a cold snap when it feels like it’s not up to the job.

“With LP gas you feel heat immediately, it’s warm to the hand” but a heat pump takes longer to change temperature when it’s really cold outside, said Chris Essler of Deering.

Essler replaced the oil heat system in his Deering home with heat pumps seven years ago. His story is interesting because it reflects a basic truth that transcends heating and cooling technology: Insulation is vital.

He lives in a log house and he’s glad he bought it. But you can’t insulate walls made of logs.

“It’s very inefficient. In January and February, it tends to fall behind against the loss curve,” he said, meaning that heat leaks out of his house faster than the heat pump can bring it inside. “They work far better in a fully insulated home.”

Most people who retrofit with heat pumps leave their old system in place as a backup to help during the occasional polar vortex, although some commenters mentioned that they’ve never had to use it. Many units also have resistance heat built in, a less-efficient electric heating method that can boost output when it’s very cold.

Essler, who has had his system longer than many people, pointed out one other drawback: While there’s no problem finding somebody to sell and install a system, finding somebody to do maintenance is another matter, especially if you’re out in the country.

“They’re a pretty heavily technical system. I’ve made calls to six different heating and cooling companies (for maintenance) without getting a call back,” he said. “There’s a shortage of manpower and expertise.”

As for operating costs, there’s no guarantee that switching to heat pumps will save you $1,000 a year like the Greyes. Online comments about cost savings ranged from no savings at all to saving quite a lot, although comparison is difficult if other changes are made at the same time. Operation certainly won’t be more expensive than fossil fuels unless something really weird is happening.

As for installation costs, that’ll be five figures – at least 10 grand and perhaps much more. They’re usually more expensive than a comparable oil or propane furnace. Costs are falling as heat pumps become more common but overcoming this up-front cost is why the government is helping out.

The bottom line of my request is that nobody who actually has heat pumps told me they regretted getting them and most were enthusiastic fans. By next year I plan to be among their number.