It is the last day of the year, 2025.
The Weather Channel headline reads “Arctic Blast Grips Us.” The Old Farmer’s Almanac predicted colder-than-normal weather for our region this winter—and that forecast has proven accurate. As heat pump owners face their first real test of extreme cold, many are discovering that heat pump setbacks—the practice of lowering your thermostat overnight—don’t work the same way they did with traditional furnaces.
Today marks Day 365 of 2025, with 78 days remaining until spring. (I’m already flipping through the Whole Seed Catalog, dreaming of warmer days.)
This kind of weather tests heating systems to their limits. Understanding how your heat pump operates during extreme cold makes the difference between comfort and frustration.
I recently read that the Farmers’ Almanac would cease publication this year and rushed to Tractor Supply to grab what I thought might be a final copy. It turns out I learned something new in the process—there are actually two Farmer’s Almanacs: the Farmers’ Almanac (ending publication after 107 years) and the Old Farmer’s Almanac, founded in 1792 and still going strong after more than two centuries.
I’ve been enjoying my copy of the Old Farmer’s Almanac, diving into practical articles on gardening and household tips while dreaming of warmer weather and sunny days ahead. There’s something grounding about traditional knowledge, especially during the coldest stretch of winter.
When temperatures plummet like this, your heating system isn’t just a convenience—it’s essential for safety and comfort. Whether you’re running a modern heat pump, an old cast-iron boiler, or anything in between, now is the time to make sure everything is working properly.
This year didn’t feel particularly dramatic on a day-to-day basis, but when I take a step back and look at what changed at Shelter Air, I realize just how much growth happened.
In 2025, we:
We spent significant time this year learning new technologies, particularly air-to-water heat pump systems. These emerging solutions remain relatively uncommon in residential applications but offer remarkable efficiency and comfort when properly designed and installed.
We also refined our approach to whole-home comfort and building performance. Heating and cooling are just one piece of a larger puzzle that includes air quality, humidity control, ventilation, and building envelope performance.
Our deep cleaning process for mini-split heads has become increasingly popular as homeowners discover the difference proper maintenance makes. We discovered a lot of yucky stuff inside these systems! We’ve also expanded our fresh air ventilation services with ERV (Energy Recovery Ventilator) installations—solutions that are making a real difference for families dealing with persistent dust, cooking odors, smoke, pet dander, and general air quality concerns.
None of this happened overnight. It came from showing up every day, learning from challenges, and improving what we do one step at a time.
If you haven’t scheduled your seasonal maintenance yet, now is an excellent time. During extreme cold snaps like this one, we can catch small issues before they cascade into major problems—especially when you’re relying on your heating system around the clock.
While many people know us for modern heat pump installations and building science approaches, we also work on old crusty boilers, ancient furnaces, and everything in between. If it heats your house, we can take care of it.
Heat pumps have transformed home heating over the past decade, and modern cold-climate units are remarkably capable—but they operate fundamentally differently than traditional heating systems. This difference becomes especially important during weather like we’re experiencing now, particularly when it comes to heat pump setbacks and thermostat programming.
Traditional furnaces and boilers generate heat through combustion, creating very hot air or water that’s then distributed throughout your home. A gas furnace might produce air at 120-140°F, delivering a strong blast of warmth whenever the thermostat calls for heat. These systems typically operate in simple on/off cycles—either running at full capacity or not running at all.
Heat pumps, by contrast, move heat rather than create it through combustion. Even in cold weather, there’s heat energy in outdoor air. (Until you reach absolute zero at -459.67°F—so we’re nowhere close.) Modern cold-climate heat pumps extract this heat and concentrate it indoors.
However, the air coming from a heat pump typically ranges from 85-105°F—noticeably cooler than traditional furnace air. This isn’t a deficiency; it’s how the technology works. To compensate, heat pumps use modulating compressors and variable-speed fans that allow them to run continuously at lower speeds, maintaining steady comfort rather than cycling on and off.
Here’s where many heat pump owners run into trouble, especially during extreme cold: the traditional wisdom about heat pump setbacks doesn’t apply. It’s another thing from the ’90s that refuses to go away.
For decades, energy experts recommended setting your thermostat back at night or when you’re away. You’d let your home cool down by 5-10 degrees, then warm it back up when needed. This strategy made perfect sense with old single-stage furnaces that either ran at full blast or didn’t run at all.
Personally, I have an old oil boiler that makes a ton of noise when it operates. I turn it down at night so I don’t get woken up every 15 minutes or so—I get it. We have a new heat pump, thanks to Carrier, but have been so busy with our clients that we haven’t gotten the chance to commission the system. I can’t wait.
However, with heat pumps, especially during very cold weather, heat pump setbacks can backfire spectacularly.
Recovery Takes Significant Time and Energy
When you ask a heat pump to raise your home’s temperature by 5-10 degrees during a cold snap, it may struggle to keep up. If outdoor temperatures are in the single digits or below zero, the system will run at maximum capacity for extended periods. It consumes more energy than it would have used to simply maintain temperature.
Emergency Heat Kicks In
Many heat pump systems have backup resistance heat (electric strips) that automatically engage when the system can’t meet demand quickly enough. This emergency heat is essentially a giant toaster. It costs 2-3 times more to operate than the heat pump itself. A deep setback during extreme cold almost guarantees you’ll trigger this expensive backup heat.
Comfort Suffers
Because heat pumps produce lower-temperature air, the recovery period feels uncomfortable. You might have lukewarm air blowing for hours while your home slowly warms up—not the quick blast of hot air you’d get from a furnace. This is when people become concerned about their system.
The System Works Harder in the Coldest Conditions
Heat pump efficiency decreases as outdoor temperature drops. During an arctic blast, outdoor temps are at their lowest. You’re asking the system to work at its least efficient operating point and do extra work to recover from a setback. It’s the worst possible combination.
Let’s say you set your heat pump back from 68°F to 62°F overnight, and outdoor temps drop to 5°F. At 6 AM, you want your home back to 68°F for breakfast.
Your heat pump is now fighting a 6-degree indoor recovery demand while extracting heat from 5°F air outside—near the limit of its capacity. It runs at maximum output for 2-3 hours, possibly triggering backup heat, consuming significant electricity, and still leaving you chilly during your morning routine.
If instead you’d maintained 68°F all night, the system would have run steadily at low speed. It would sip electricity efficiently, keep you comfortable, and likely use less total energy. It’s like a car—it takes less fuel to maintain a speed than it does to accelerate quickly.
The simplest and most effective approach? Use a smart thermostat and rely on its “away” and “sleep” modes with minimal setbacks—perhaps just 1-2 degrees.
Quality smart thermostats like Ecobee can learn your heat pump’s characteristics and adjust strategically. They might:
During extreme cold like we’re experiencing now, many heat pump owners find that the best strategy is no heat pump setback at all. Just let the system maintain temperature continuously.
Beyond heat pump setbacks, heat pump owners should be aware of other potential challenges during arctic blasts:
Heat pumps must periodically defrost their outdoor coils when frost builds up. During these 5-15 minute cycles, the system temporarily reverses. It actually blows cool air inside while warming the outdoor coil. In extreme cold, defrost cycles become more frequent. This is normal, but it can feel disconcerting. Some systems will use the resistant heat coils during this mode to offset any discomfort.
All heat pumps lose capacity as outdoor temperature drops. A conventional unit rated for 36,000 BTU at 47°F might only deliver 20,000 BTU at 5°F. Most of the cold climate heat pumps we use from manufacturers like Carrier, Mitsubishi, and Bosch operate at 100% down to -15°F or even lower!
Heat pumps excel at maintaining temperature but struggle to overcome massive heat loss. During extreme cold, air leakage that barely mattered in milder weather becomes a serious problem. This is why we emphasize building performance. Proper air sealing and insulation make heat pumps far more effective. Building Science is core to everything we do.
Outdoor units need clear airflow. Heavy snow, ice buildup, or blocked drainage can reduce performance or cause shutdowns. Regular clearing around the outdoor unit matters during weather like this. In New York we place units 6″ to 18″ off the ground, depending on the region, to avoid problems with snow.
Heat pumps are incredibly efficient, increasingly capable in cold climates, and represent the future of home heating. However, they require understanding and different operating strategies than traditional systems. The old practice of deep heat pump setbacks simply doesn’t work with modern modulating technology.
If you’re struggling with your heat pump during this arctic blast, or if you’re concerned about high heating bills, let’s talk. Sometimes the solution is as simple as adjusting your thermostat strategy. Other times, we may identify maintenance needs, sizing issues, or building performance problems that should be addressed.
at Shelter Air.
The New Year is an excellent time to revisit home comfort projects you’ve been considering but haven’t quite tackled yet.
Because of the relationships we’ve built and the volume of work we’ve been doing, some of our suppliers have sharpened their pencils. We can pass savings along to homeowners.
Combined with NYSERDA’s rebate programs, homeowners can save thousands of dollars when installing heat pump systems. The economics are often far more attractive than many people realize.
If you’re curious about what a properly designed heat pump system could look like for your home—or if you want to understand whether your existing system is performing as it should—let’s talk.
It’s cold and windy as we say goodbye to 2025—and honestly, it’s been quite an adventure.
Stay warm. And if a friend or neighbor is struggling with their heat, let them know Shelter Air has them covered.
We’re here for maintenance, heat pump installations, and service on everything from old boilers and furnaces to modern mini-splits.
Happy New Year from all of us at Shelter Air.
