Some of the stations in Antarctica use heat pumps. They have been proven to work effectively at -53°C (-64°F) and do so reliably.
Are they more efficient at more reasonable temperatures? Yes. But they still work even when it’s very cold outside.
How well a heat pump works in cold temperatures obviously depends what temperatures it was designed to operate at. Don’t waste your money on a model that is designed to operate in a different climate. In fact a lot of heat pumps aren’t even capable of heating at all - they can only output cold air (which they can do even if it’s stinking hot outside by the way).
Some of the stations in Antarctica use heat pumps. They have been proven to work effectively at -53°C (-64°F) and do so reliably.
Are they more efficient at more reasonable temperatures? Yes. But they still work even when it’s very cold outside.
How well a heat pump works in cold temperatures obviously depends what temperatures it was designed to operate at. Don’t waste your money on a model that is designed to operate in a different climate. In fact a lot of heat pumps aren’t even capable of heating at all - they can only output cold air (which they can do even if it’s stinking hot outside by the way).