How heat pumps work

Just as its name implies, a heat pump “pumps heat” from where it’s hot to where it’s cold.
Air-source heat pumps pull heat out of the ambient air and use the refrigeration cycle to efficiently transfer it to where it’s needed (i.e., into your house during the cool months) or from where it’s not needed (from your house during the hot months).

Your refrigerator is actually a heat pump, removing heat from inside the refrigerator and contents to outside.

Why air-source heat pumps traditionally don’t work in New Jersey?

As the temperature of the air outside falls, so does the amount of heat it contains – That’s why it feels cold!
As the amount of heat in the air decreases, the heat pump has to work harder to compensate in order to maintain the amount of heat the thermostat demands be brought into the building.

This is because:
1) The heat pump’s compressor must work harder to elevate the refrigerant from its initially lower temperature and
2) More less-dense (due to lower temperature) refrigerant is required to transfer same amount of heat.

With the exception of the Hallowell all temperature air-source heat pump, heat pumps reach their limit to extract heat from the air as they reach 32° Fahrenheit. Once these heat pumps meet their limits, then their “back-up” heating systems (normally electric strip-heat) kick in.

This implies that at lower temperatures, you’re using extremely expensive and inefficient electric heat (i.e., Coefficient of Performance = 1) to heat your house. This is why, despite all their hype, heat pumps received a bad reputation in New Jersey

Why is the Hallowell International air-source heat pump different?

Hallowell’s heat pump, with its unique patented Opti-Cycle™ process, is optimized for “mixed climates” like New Jersey with cold winters and hot summers.

As temperatures get colder, the second cylinder on the primary compressor is engaged to provide more capacity to the refrigeration process thus enabling the Hallowell unit to better extract heat from the air. If the two cylinders of the primary compressor are deemed inadequate by the advanced electronics incorporated in the heat pump, then the larger volume “booster compressor” kicks in to help pump more (lower density, due to the colder temperatures) refrigerant through the system. An additional heat exchanger (called “the economizer”) is also engaged to “squeeze” as much heat from the pump’s refrigerant as possible.

This implied that at 32°F, the Hallowell unit will produce $2.80 in heating performance per $1.00 used to run it (while other heat pumps max out at $1.00).

At 0°F, the unit will produce $2.21, and $1.93 at 30° below zero.