Balance point
Heat pump balance point calculator
“Balance point” gets used for two different things: whether your heat pump can physically keep up (thermal), and whether it is still the cheaper choice (economic). Calculate both below.
Two balance points, not one
Thermal balance point
A capacity question. Your heat pump’s heating capacity falls as it gets colder outside; your house’s heat loss rises. The thermal balance point is where those two lines cross — below it, the heat pump alone can’t hold your setpoint, whatever it costs.
Economic balance point
A cost question. Your heat pump’s efficiency (COP) falls as it gets colder; at some outdoor temperature, its cost per unit of heat rises above your furnace fuel’s. That crossing point is the economic balance point, and it can sit well above or below the thermal one.
Calculate your own
Capacity and COP at 47°F, 17°F and 5°F outdoor are published for most AHRI-rated heat pumps (check your model’s AHRI certificate or NEEP cold-climate listing). Design heat loss and design temperature come from a Manual J load calculation; 70°F indoor is a reasonable default.
Thermal balance point
The outdoor temperature where your heat pump’s capacity exactly meets your home’s heat loss. A comfort number, not a cost one.
Thermal balance point
28 °F
Economic balance point
The outdoor temperature where your heat pump and your furnace or other heat cost the same per BTU. A single-COP-curve estimate — the main tool weighs your whole winter’s hours instead.
Economic balance point
39 °F
Get the one number that minimizes cost all winter
Enter your ZIP, your heat pump model and your rates, and get the lockout temperature that costs you least, with the range it is sensitive to.
Questions
- What is a heat pump balance point?
- The outdoor temperature where two things cross. The thermal balance point is where your heat pump's capacity exactly meets your home's heat loss — a comfort fact. The economic balance point is where your heat pump and your furnace or other heat cost the same per BTU — a cost fact. They are rarely the same temperature.
- What is the economic balance point of a heat pump?
- The outdoor temperature below which your furnace or boiler costs less than running the heat pump for the same amount of heat, given your prices and your heat pump's efficiency at that temperature.
- Is the balance point the same as the lockout temperature?
- Not necessarily. Many thermostats let you set the compressor lockout anywhere, including well below the balance point, if you are willing to trade some efficiency for simplicity, or above it for comfort margin. heatpump.blue's main tool recommends the lockout that minimizes your annual cost across your whole winter, which uses the economic balance point idea but is not limited to a single COP snapshot.
- What is thermal balance point in heat pump operation?
- The outdoor temperature where your heat pump, running flat out, produces exactly as much heat as your house loses. Below it, the heat pump alone cannot keep the house at setpoint and needs help from the furnace or other heat to stay comfortable — regardless of what the setting costs.