Quick answer
A balance point temperature is the outdoor temperature at which a heat pump's heating output exactly equals the home's heat loss, so that below it the heat pump alone cannot keep up and backup heat must help.
Installers also speak of a building's thermal balance point, where free heat from sun and appliances covers the loss, and an economic balance point, where gas becomes cheaper than the heat pump.
Quick facts
The key facts about Balance Point Temperature, with sources:
- Type
- Design and control setting for heat pumps
- Found from
- Heat pump capacity vs temperature, and the Manual J heat loss line 2
- Cold-climate test points
- Capacity at 5°F ≥70% of capacity at 47°F; COP ≥1.75 at 5°F 1
- Building balance point
- Near 65°F for a typical home; the basis of degree days 4
- Below the balance point
- Backup heat (strips or a furnace) makes up the gap
- Related setting
- Thermostat aux-heat lockout and dual-fuel switchover
Key takeaways
- Above the balance point the heat pump does the job alone; below it, backup heat runs.
- A lower balance point means less backup heat and lower bills.
- Cold-climate heat pumps hold more capacity at 5°F, which pushes the balance point down 1.
- Tightening and insulating the house also lowers it.
- It sets the thermostat's aux-heat lockout and the dual-fuel switchover.
What the balance point is
A house loses more heat the colder it gets outside. A heat pump makes less heat the colder it gets outside. Plot both against outdoor temperature and the two lines cross. That crossing is the balance point.
Above it, the heat pump has spare capacity and cycles on and off. At it, the heat pump runs nonstop and just keeps up.
Below it, the house loses heat faster than the heat pump can add it, so backup heat, often electric strips in the air handler or a gas furnace, fills the gap.
The term has two cousins. The building balance point is the outdoor temperature at which the house needs no heat at all, because sun and appliances cover its loss; degree days use 65°F for that reason 4.
The economic balance point is where gas heat becomes cheaper than heat pump heat, used to set a dual-fuel switchover.
How to find a balance point
- Manual J → heat loss at the winter design temperature 2
- Draw the heat loss line from that point to zero at about 65°F
- Maker data → heat pump capacity at 47°F, 17°F and 5°F
- Draw the capacity line through those points
- Where the lines cross → thermal balance point
- Gap between the lines at design temperature → backup heat size
How it works in practice
Heat pump capacity falls with temperature because there is less heat in colder air and the compressor must lift it further. Capacity data at 47°F and 17°F is on the AHRI listing; good makers also publish 5°F and lower in extended data.
ENERGY STAR's cold-climate tier sets a floor: heating capacity at 5°F must be at least 70% of capacity at 47°F, and COP at 5°F must be at least 1.75 1.
A unit that meets that holds its output much better than an older single-speed model, so its capacity line stays higher and crosses the heat loss line at a colder temperature.
The thermostat uses the result. An outdoor-temperature lockout keeps the backup strips off above the balance point, so they cannot run just because the house is recovering from a setback.
Sources: [1]
Three kinds of balance point
| Kind | Where the lines cross | What it sets |
|---|---|---|
| Thermal (heat pump) balance point | Heat pump output = house heat loss | Backup heat need and aux lockout |
| Building balance point | Free internal and solar gains = house heat loss | When heating starts at all; degree-day base 4 |
| Economic balance point | Heat pump cost per BTU = fuel cost per BTU | Dual-fuel switchover temperature |
Worked example: two heat pumps, one house
Assume a house that loses 40,000 BTU/h at a 5°F design temperature and zero at 65°F (assumed Manual J result).
Both heat pumps deliver 36,000 BTU/h at 47°F. Unit A just meets ENERGY STAR's cold-climate capacity floor of 70% at 5°F 1; Unit B keeps an assumed 55%. Capacity is drawn as a straight line between 47°F and 5°F.
| Item | Unit A (cold-climate floor) | Unit B (assumed 55%) |
|---|---|---|
| Capacity at 47°F | 36,000 BTU/h | 36,000 BTU/h |
| Capacity at 5°F | 25,200 BTU/h (70%) | 19,800 BTU/h (55%) |
| House loss line | 40,000 × (65 − T) ÷ 60 | Same |
| Balance point (lines cross) | About 21°F | About 24°F |
| Shortfall at 5°F | 40,000 − 25,200 = 14,800 BTU/h | 40,000 − 19,800 = 20,200 BTU/h |
| Backup heat at 5°F (÷ 3,412 BTU per kWh) | About 4.3 kW | About 5.9 kW |
A few degrees of balance point sounds small, but every hour below it costs resistance heat at a COP of 1.0. A unit with better cold-weather capacity, or a tighter house that lowers the loss line, cuts those hours. Real capacity curves are not perfectly straight, so designers read the maker's table.
Where balance point shows up
- In a Manual S heat pump selection, as the backup heat check 3.
- In thermostat installer settings: aux heat lockout, compressor lockout, dual-fuel switchover.
- On an energy audit report, as the effect of air sealing and insulation.
- In maker data as capacity at 47°F, 17°F and 5°F.
Why a low balance point helps
What it does well
- Fewer hours of costly backup heat.
- Smaller backup heat strips or furnace runtime.
- More of the winter served at heat pump efficiency.
Where it falls short
- Pushing it lower may mean a bigger or pricier heat pump.
- An oversized heat pump can short-cycle and dry the air poorly in summer.
- Lab capacity data may not match real defrost-heavy weather.
Limits of the calculation
The house line is an estimate. It rests on a Manual J heat loss, which is only as good as its inputs 2. The capacity line leaves out defrost: in humid cold weather, the outdoor coil frosts and the unit spends time defrosting, which trims real output near 30°F to 40°F.
Wind, sun and internal gains also shift the real crossing from day to day. Treat the balance point as a design number, not a fixed physical constant.
How the balance point affects running cost
Below the balance point, every BTU the heat pump cannot supply comes from backup heat. Electric strips run at a COP of 1.0, so they use two to three times the electricity per BTU of a heat pump running at a seasonal COP of 2 to 3.
For dual fuel, the switchover is often set at the economic balance point, which depends on your local electric and gas prices. Our electric vs gas price ratio research shows how that varies by state. The heat pump savings calculator estimates the effect on bills.
How a contractor sets it
- Get the Manual J heating load at the design temperature.
- Pull the heat pump's capacity at 47°F, 17°F and 5°F from maker data.
- Plot both and find the crossing.
- Size backup heat for the shortfall at design temperature.
- Set the thermostat's aux heat lockout near the balance point, and any dual-fuel switchover near the economic balance point.
- Review settings after air sealing or insulation work.
Keeping the balance point low
- Keep filters clean; low airflow cuts heat pump output.
- Keep snow and ice clear of the outdoor unit.
- Seal air leaks and add attic insulation; that lowers the house loss line.
- Avoid big setbacks that call aux heat on recovery, unless your thermostat manages it.
Warning signs
- Aux heat runs on days well above your balance point.
- Heat pump never runs below a high lockout temperature, so gas or strips do all the work.
- Bills jump in mild weather.
- The outdoor unit is buried in ice and never defrosts; call for service.
Standards that bear on it
No code sets a balance point. The standards that shape it are the ratings and sizing rules.
ENERGY STAR's cold-climate tier requires 5°F capacity of at least 70% of the 47°F figure and a COP of at least 1.75 at 5°F 1.
DOE sets heat pump HSPF2 floors: 7.5 for split systems made from 1 January 2023 5.
Manual S checks heat pump heating capacity and backup heat as part of equipment selection, which the IRC requires through M1401.3 3.
Balance point vs related terms
| Term | What it is | Relation |
|---|---|---|
| Balance point | Where output meets heat loss | Sets backup heat use |
| COP | Heat out per unit of energy in | Falls with temperature |
| HSPF2 | Seasonal heating efficiency | Averages over a test climate |
| Design temperature | Near-coldest local condition | Sets the heat loss endpoint |
| Heating degree days | Season-long heating need | Based on a 65°F building balance point |
Common misconceptions
- Myth The balance point is fixed by the heat pump.
- Reality It depends on the house too; air sealing lowers it.
- Myth Below the balance point the heat pump shuts off.
- Reality It keeps running and supplies most of the heat; backup only fills the gap.
- Myth Thermal and economic balance points are the same.
- Reality One is about capacity, the other about fuel prices.
Why climate decides how much it matters
In Georgia or Texas, winter design temperatures are mild, so many homes rarely drop below the balance point. In Ohio or eastern Washington, many hours fall below it, so a cold-climate unit or dual fuel pays off. Heating degree days give a quick sense of how much of your winter is cold.
When it matters to you
Ask for the balance point when you buy a heat pump in a place with real winters, and when you set up dual fuel. A good installer can show the crossing on a simple chart.
Next step: compare models on our best cold-climate heat pumps page and check the switchover with the heat pump vs furnace tool.
Questions about Balance Point Temperature
What is a heat pump balance point?
It is the outdoor temperature where the heat pump's heating output equals the house's heat loss. Above it the heat pump keeps up alone; below it, backup heat such as electric strips or a furnace helps.
What is a typical balance point?
It varies widely with the house and the heat pump, so there is no single figure. A tight house with a cold-climate heat pump can have a balance point well below 20°F; a leaky house with an older single-speed unit may be near or above freezing.
How do I lower my heat pump's balance point?
Reduce the home's heat loss with air sealing and insulation, or choose a heat pump that holds more capacity in the cold. ENERGY STAR cold-climate units must keep at least 70% of their 47°F capacity at 5°F.
What is the economic balance point?
It is the outdoor temperature where heat from a gas furnace becomes cheaper than heat from the heat pump, based on local fuel prices and efficiencies. It is used to set the switchover on dual-fuel systems.
Should aux heat be locked out above the balance point?
Usually yes. An outdoor-temperature lockout stops costly strip heat from running when the heat pump can keep up. Many installers set it near the thermal balance point, with care for defrost and recovery.
Does the heat pump stop below the balance point?
No, unless a compressor lockout is set. It keeps running and supplies most of the heat. Backup heat only covers the shortfall.
How is the balance point calculated?
Plot the home's heat loss against outdoor temperature from a Manual J, and plot the heat pump's capacity from maker data. The temperature where the lines cross is the balance point.
What is a building balance point?
It is the outdoor temperature at which a house needs no heating, because sun, people and appliances cover its losses. Degree-day calculations use 65°F as a standard stand-in for it.
Sources
- ENERGY STAR, Air Source Heat Pumps Key Product Criteria, retrieved .
- ACCA, Manual J Residential Load Calculation (8th Edition), retrieved .
- ICC / ACCA, An Overview on ACCA's Residential HVAC System Design Process (PMG educational program), retrieved .
- U.S. EIA, Energy Explained: Degree days, retrieved .
- eCFR, 10 CFR 430.32, Energy and water conservation standards (version of 1 September 2026), retrieved .
Expert review
Written by the HyreHVAC Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Cold-climate capacity and COP floors from ENERGY STAR; HSPF2 floor from 10 CFR 430.32; method from ACCA and ICC material, read 10 October 2026. The worked example solves two straight lines with assumed loads and an assumed 55% unit, labelled; Unit A uses the ENERGY STAR floor.
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