High-performance heat pumps can operate in temperatures well below zero, so why do they have a reputation for being impractical in extreme cold?
Today, heat pumps serve as efficient, cost-effective heating systems everywhere from Maine to Alaska, but that wasn't always the case. Before the technological advances that we see implemented in current cold climate heat pumps, heat pumps simply weren't able to pull enough heat from outside when temperatures dropped to efficiently and effectively warm a home. But gone are the days of heat pumps being limited to mild and warm climates. In this article, we explain how heat pumps work in extreme cold when you should consider other technology, and where to find cold climate heat pumps.
Heat pumps are an efficient and effective source of heat even in extremely cold climates.
Not all heat pumps are designed for extreme cold – there are certain efficiency criteria cold climate heat pumps must meet.
Generally, cold climate heat pumps are an efficient heat source down to -15 degrees Fahrenheit.
A supplemental heat source might be necessary to back up a heat pump system when temperatures reach below its minimum operating temperature.
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Contrary to popular belief, heat pumps are absolutely capable of keeping your home warm in subzero temperatures – but not all heat pumps. More specifically, cold-climate heat pumps work well in cold climates. While New Englanders and Floridians alike are able to enjoy year-round comfort from heat pumps, a heat pump used in Florida probably won't cut it in a New England winter. Enhancements in heat pump technology, like variable compressors and cold climate refrigerants, expand the capabilities of heat pumps in cold weather.
Cold climate refrigerant
Refrigerant is what collects heat energy from the outside air in a heat pump system. The transfer of heat is contingent on the outside air warming the liquid refrigerant and, ultimately, vaporizing it. Cold climate heat pumps use refrigerants with a lower boiling point to allow for their continuous flow through the heat pump system even at low ambient temperatures.
Variable speed heating
Variable speed heating is an important contributor to the feasibility of heat pumps in extreme cold. Instead of blasting air into your home at full capacity and then off when the temperature reaches the thermostat setting, variable speed systems run continuously to maintain the desired temperature. This allows for the system to ramp up and down at a lower setting rather than repeatedly turning on and off.
Minimum operating temperature
Consider the temperature of your local climate during the coldest winter months: is the heat pump system you intend to install capable of performing then? Will you need a backup system to kick on when the temperature drops? Models designed for extreme cold will clearly state the minimum operating temperature on their website or directly on the packaging or unit.
The Heating Seasonal Performance Factor, or HSPF, rates the efficiency of a heating system. HSPF ratings help us to understand the amount of energy a specific system requires to heat a space effectively and comfortably. The higher the HSPF, the less electricity the system needs to keep a home at its desired temperature.
Once you're settled on the technology, make sure you work with a trusted installer. Up to 90 percent of air source heat pumps are performance-compromised due to installation or maintenance faults, according to the U.S. Department of Energy (DOE), and it's especially important to avoid efficiency-degrading installation errors for cold climate heat pumps. Luckily, contractors on the EnergySage Marketplace are pre-vetted, and our independent Energy Advisors are here to help you understand and compare heat pump quotes.
With the advanced technology available in cold climate heat pumps today, a backup heating system might not even be necessary. However, a functional source of heat – especially during extreme cold events – provides safety and security to a home. For this reason, some heat pump users maintain a backup heating system, like a furnace or a boiler, in the case of very low temperatures.
Fortunately, heat pumps easily sync with backup heating systems to provide users with peace of mind during the coldest months. Furthermore, an additional heat source doesn't always come with an additional price tag; removing your old heating system is not required when installing heat pumps. Work with a trusted installer to find the best-fit system or mix of systems for your home!
Even with recent technological advancements, there are still instances when heat pumps won't serve as effective heating systems. Generally, heat pumps remain an efficient source of heat down to approximately -15 degrees Fahrenheit. If you live in a climate that regularly dips below that temperature, you'll likely need a backup heating system for very cold days. Currently, the National Renewable Energy Laboratory (NREL) is studying the effect demand has on a heat pump's performance, how efficiency drops in colder temperatures, and how to appropriately size a heat pump for a home. As heat pump technology continues to evolve, the threshold is likely to reach lower and lower temperatures.
Between government-issued incentives and programs like the Department of Energy's Residential Cold Climate Heat Pump Challenge, the heat pump market is more efficient and affordable than ever. As demand grows and more manufacturers incorporate heat pumps into their HVAC offerings, the capabilities of cold-climate heat pumps are also likely to continue to expand. Below is a snapshot of some high-performance extreme cold heat pumps on the market today:
High-performing cold climate heat pumps
Cold Climate Technology Product Line
Minimum Operating Temperature
For a comprehensive list of air source heat pump options, check out the Northeast Energy Efficiency Partners (NEEP) Cold Climate Air Source Heat Pump List. You can filter by brand, model number, ducting configuration, and more! With over 800 products currently listed, it may be helpful to consult a trusted installer or an EnergySage Energy Advisor to better understand the credentials of the best-fit heat pump for you and narrow down your search on NEEP's list.
Heat pumps pair naturally with solar panels to offer energy efficiency, savings, and emission-free heating and cooling for your home. Connect with pre-screened installers in your area on the EnergySage Marketplace to receive solar quotes today! Just leave a note to let installers know you're interested in heat pumps. Still, have questions? When you sign up for the Marketplace, we'll connect you with an Energy Advisor from our team (free of charge) to help guide you through every step of the way.