An updated outside unit for a ducted heat pump system is shown in Troy. It’s more compact, and it generates heat well below zero outside temperatures. Photo by Dana Wilde

At our house in Troy, we ran a sort of Frankenstein monster to heat our house for many years.

The different parts sutured together over the years included the original oil burner from when the house was new in 1986; a backwoods-installation wood stove in the cellar; a kerosene space heater to help out the wood stove; a couple of limited-use electric space heaters upstairs; and, starting in 2009, a ducted heat pump system that had drawbacks. One of the drawbacks being that the first iteration of it never worked right and crashed permanently in 2011 (see Backyard Naturalist column, Oct. 24). Another being that the replacement unit only generated heat down to 25 degrees outside temperature, at which point we turned on the oil burner.

Still, this monstrosity of many pieces did save us some money over oil and somewhat reduced our carbon emissions.

In about 2020, I started thinking the heat pump technology must have improved vastly since the 25-degree-limit unit was installed in 2011. So I started making phone calls to try and find the upgrade I believed must exist. No dice. None of the heat pump people I called worked on ducted systems. It was wall-mounted mini-splits or nothing, apparently.

I had several runs at this from about 2020 to 2023. When the 2011 unit manufacturer’s agent told me no upgrade existed, I kind of gave up. We did not have enough money to put yet another piece in the form of a mini-split on the Frankenstein monster. It would be like solving worn tires by having more wheels installed on your car.

So we continued to heat the house by heat pump when it was above 25, and by oil, wood and kerosene supplement when it was below 25.

In 2022, our handyman neighbor installed a heat pump hot water heater for us. This meant we burned still less oil. This was great until the oil burner crashed in the spring of 2023. Now I had to figure out how to heat the house when the temperature dropped below 25.

All avenues of inquiry pointed to the wall-mounted mini-split heat pump, with quotes from five different installers, government grants and rebates, and unavailability of an upgrade for the old 2011 unit. One of the installers was skeptical of a plan to use a mini-split to heat the house. But the other four were enthusiastic — what could go wrong? We had one installed in the living room in June last year.

The “dry” setting on the mini-split worked great. It removed an edge of discomfort from some terrible suffering in my house during that summer’s heat waves.

On a few stray days when I asked it for heat, though, it was not so cooperative. I could not get an even temperature in any part of the house.

If I wanted the kitchen warm, I had to crank up the thermostat to about 75. The living room would then get near 80. If I ran it enough to keep the living room at about 70, the kitchen got cold.

It soon became clear that the unit did not really know what the temperature was in the living room, either. On consulting with the installer and reading the (somewhat sketchy) operating instructions, any problem did not appear to be operator error.

Eventually, I figured out what was happening. A basic fact of thermodynamics is that heat rises. So this heater is installed near the ceiling. The first place the heat it generates settles is along the ceiling. There’s a fan in the unit whose job is to push air down and around. But heat rises no matter where you push it, and collects up high before seeping down. Up high, the temperature would be 74. Down below, where I was sitting in my chair, it would be 66. Cold hands and fingers.

Another piece of the puzzle was the unit was mounted right next to a window. A fairly tight window, but a cold spot nonetheless. So the thermostat reading on the unit mostly had nothing to do with what was happening down near the floor.
Meanwhile, it was getting colder outside, and in the kitchen. Even though it’s more or less a straight shot from the living room through a wide doorway into the kitchen, not a lot of warm air wandered through. The bathroom and a bedroom were even colder because the warm air had to go around corners.

So guess what I did in October and November when the outside temperature was generally above 25. I ran the old ducted heat pump, warming up all the rooms. Unfortunately, when the temperature went below 25 I was going to have to turn the mini-split back up.

As it got colder in November, I did some experiments with oil-filled space heaters. I discovered that one each running in the kitchen and bedroom helped. The bathroom remained chilly. Chillier and chillier, to paraphrase Alice’s words in wonderland.

The fifth installer’s skepticism was borne out. The mini-split, which cost more than $5,000, was basically heating just one room. More or less exactly what one oil-filled space heater, which cost about $125, could do.

There was also the extremely annoying phenomenon of the mini-split’s fan basically never turning off. It background-hummed for hours and days at a time, like endless highway traffic heard from a distance. I could not get used to it.

To heat the house using the mini-split, I would need to run at least two space heaters; keep a fire going in the inefficient wood stove in the cellar (i.e., my old bones up and down the stairs about 10 times a day); listen to the fan; and on the coldest days, light the kerosene heater.

The installers’ proposed solution to the whole problem was to install more mini-splits and extra fans. It would be a humming labyrinth of carefully directed drafts.

This all looked to me like the Revenge of the Frankenstein Monster.

Feeling defeated, I got some quotes on a propane system — to be used only when the temperature went below 25. I was going to have to take out a second mortgage. So I decided to have one last, desperate run at trying to get an upgrade to the old 25-and-above ducted heat pump.

Long story short, on the very last call I made (“If these guys can’t do it, it’ll be propane”) an outfit in Holden said they work on ducted systems. They came right over, sized up the situation, and scheduled a time. It took one day’s work to replace the old components. When they switched on the system to test it, in less than five minutes all the rooms in the house were warmer than they had been for six weeks.

With government incentives, the upgrade cost about two-thirds of the propane system quotes. The contract for the mini-split had a money-back guarantee in it, and although it took some phone calls, the mini-split eventually got uninstalled. And, commendably on the installer’s part, cheerfully.

The ducted heat pump system works exceptionally well. It’s better than the baseboard heat driven by the oil burner. Quieter. And so far, much less expensive. (We’ll see how long this lasts, until we find out how much of our money the PUC feels belongs in the bank accounts of wealthy utility shareholders in Spain.)

This is a cautionary tale, not about heat pumps, but about new technology. We got badly burned on the original heat pump installed in 2009. Then, the mini-split did not heat the house as depicted.

Some friends speak highly of their mini-splits; others gripe about the fan and limitations on heat circulation. You just want to make sure how much heat will actually get pushed down from the ceiling, where most people do not spend much time, into the places where you usually live, before you hook up one. Or two. Or three.

Battling the human-induced warming of the planet has been a long, strange trip here in Troy. And this is apt to be just part of the first installment of a much longer story. The changing climate and the electric utilities have a lot more in store for us in coming years.

Dana Wilde lives in Troy. You can contact him at dwilde.naturalist@gmail.com. His book “Winter: Notes and Numina from the Maine Woods” is available from North Country Press. Backyard Naturalist appears the second and fourth Thursdays each month.