Heat Pumps - Efficiency, Costs, Risks and Feasibility

I was wrong in thinking they were no good in freezing weather, but still...

“Wired” writes in “Don’t Believe the Biggest Myth About Heat Pumps” that heat pumps are much more efficient than gas furnaces, and are replacing them even in the coldest countries. The article was a surprise to me.

“If heat pumps don’t actually work in frigid weather, no one told the Nordic nations, which endure Europe’s coldest climates, with average winter temperatures around 0 degrees Celsius (32 degrees F). As of 2021, Norway had heat pumps in 60 percent of households. In 2022, Finland installed more of the appliances per capita than any other country in Europe, while Sweden has similarly gone all-in on the technology. In the United States, heat pumps are selling like hotcakes in Alaska, and last year Maine announced it had reached its goal of installing 100,000 of the devices way ahead of schedule.”

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I learned that heat pumps are indeed capable of heating homes in very cold weather, with the right refrigerant and of course with enough backup electric heating strips.

“Even in extra-cold places, heat pumps can use additional electric elements—space heaters, basically—to provide backup heat for a home.”

“Manufacturers make heat pumps specifically designed for cold climates, which can operate continuously as temperatures plunge into the negative.”

“Over the years, the appliances have gotten ever more efficient as their various components and refrigerants have improved. “It’s really all about the refrigerant,”

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But let’s not get carried away - heat pumps have become more efficient than gas furnaces? See if you can spot the flaw in this argument:

“When scientists are working out the efficiency of different heating techniques, they’re considering the “coefficient of performance,” or COP, which is the ratio of the energy consumed to the heat produced. If a technique is 100 percent efficient, it has a COP of 1, meaning one unit of energy going in, one unit of heat coming out. A gas furnace, for example, produces heat that blows into a home, but some of that heat is also lost during combustion, so even the most efficient models have a COP of less than 1…Overall, it’s way more efficient for a heat pump to move heat than it is to generate it, like a gas furnace does. By running on electricity instead of fossil fuels, a heat pump can manage a COP of 3, meaning three units of heat for every one unit of energy, but in extreme cases they can get up to a COP of 6, depending on the conditions and the model.” From this glowing paragraph in the same Wired piece, you’d think the “science” proves heat pumps are more efficient than gas furnaces, right? But wait…

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What is being overlooked? I knew something smelled fishy, because if heat pumps are so much more efficient, then why is it so much cheaper to heat a house with gas?

The COP described above is using the energy of the electricity as the measuring stick after it’s been delivered to the home . But what about the energy it took to convert something else, whether it be coal, oil, gas, solar, nuclear, wind, or whatever, into electricity in the first place? What about the energy it took to transmit the electricity to the home? Why do you think electricity is so much more expensive than gas?* The answer is that the gas doesn’t have to be converted into anything else. It’s used directly. The 2nd Law of Thermodynamics says that some of the useful part of energy is always lost every time it’s converted into a different form. That’s a fundamental Law; not a theory. *Gas prices are subject to the laws of supply and demand, of course, but we have plenty of supply. “The U.S. now has 227 years of oil supply, 130 years of natural gas supply, and 485 years of coal supply.” source - Energy Security and Freedom

I don’t know about you, but the efficiency I’m interested in is in my budget. The way I look at it, the most efficient way of heating my home is whatever way is cheapest. In my case, a wood stove is cheapest, because I have my own woodlot. The labor that I put into cutting up the trees and branches that get blown down every winter doubles as good outdoor exercise and at the same time keeps my little woodlot looking neater and well managed.

But back to the discussion about switching to heat pumps. If this is really such a great idea, why does it have to be subsidized? Why would it be necessary to tax fossil fuels to ‘level the playing field’? Without detailing the extra costs of switching to heat pumps, only referring to them obliquely, Wired goes on:

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“To offset such costs for the consumer, governments might implement higher taxes on fossil fuels and use the revenue to lower utility bills. They can also roll out tax rebates or grants for installing heat pumps. The US Inflation Reduction Act, for instance, provides thousands of dollars for people to switch to a heat pump and do additional electric work that may be required to run them. The bill also covers weatherization—means of weatherproofing a building, like insulation and windows—that would help a home retain heat”.

The “additional electric work” is probably referring to the need to upgrade the electric service panel to handle the increased load, besides the actual wiring of the heat pump.

Note: In Sweden's case, it had introduced a carbon tax in 1990 that pushed up the price of heating oil. Sweden also has abundant hydroelectric power plants, which generally keeps the cost of electricity under control. Canada, on the other hand, has abundant natural gas. Gas furnaces are much cleaner than oil furnaces. So heat pumps are not likely to become popular in Canada without even more subsidies. CBC News reported: “When asked in an interview if the current carbon tax and heat pump subsidies in Canada were enough for us to move past the introduction stage, Forsén [a Swedish heat pump veteran] said, "No, I think you need more." A good lessen for central planners - one size does not fit all. I didn’t take the time to dig deeper into the cases of Finland and Norway - they might be similar to Sweden.

One of the biggest HVAC manufacturers, Trane, posts this on their website: “Discover ways to save through rebates, special offers, and tax credits, including benefits from the Inflation Reduction Act (IRA).”

Consumer Reports wrote about federal and state tax credits:                            “So if you spend $10,000 on a heat pump and a heat pump water heater, you could get $9,750 back, depending on the specifics of your state's rebate program.”                No wonder lots of heat pumps are being installed!

In the case of retrofitting an old house, the ductwork may also have to be installed or replaced, and the older the house, the harder it can be to install more insulation. If you want to install a heat pump, the ideal, and of course the most efficient way, is to do it when the house is being built.

But in the casual mention of “tax rebates or grants” we find the answer to why so many heat pumps are being installed. Without subsidies, the idea would not be nearly as popular.

Now one more thing. The extra demand on the electric power grid. As if we didn’t already have enough demand to sink the ship, this is just one more huge load. With heat pumps added to EV battery charging and AI and crypto mining data centers, simultaneously with the shutting down of coal and nuclear plants and the removal of hydroelectric dams, we’re heading for catastrophic blackouts sooner or later. If it’s during a bout of extreme cold weather, watch out, Norway, Finland, Sweden, Alaska, and Maine.