- Enter rated capacity. Use the unit's useful thermal output rating in kilowatts, not its electrical input.
- Set annual operating hours. Count the hours when the geothermal heat pump is expected to run during the year.
- Estimate average load. Enter the average percentage of rated capacity delivered during operating hours.
- Apply a seasonal adjustment. Use a factor below 100% for expected temperature, cycling, or distribution losses; use 100% when no adjustment is needed.
- Review annual output. Compare useful thermal energy, average delivered capacity, and equivalent full-load hours with the site's annual demand.
Geothermal Heat Pump Annual Output Calculator
This calculator estimates the annual useful thermal output of a geothermal heat pump system. It combines rated thermal capacity, annual operating hours, average load, and a seasonal performance adjustment to estimate delivered heating or cooling energy.
The tool is useful for early feasibility studies, energy models, and comparisons between ground-source equipment options. It can indicate how much of a building's yearly thermal demand may be served and provide a starting point for operating-cost or emissions estimates.
Ground-loop temperature, pump energy, part-load performance, controls, and building demand all affect actual production. Treat the result as a planning estimate and verify it with detailed design data.
Annual operating assumptions
kW
hr / yr
%
%
Result
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Estimated annual useful thermal output
Base operating output—
Average delivered capacity—
Equivalent full-load hours—
Annual output (kWh) = Rated capacity (kW) × Operating hours × Load factor × Seasonal adjustment
Load factor and seasonal adjustment are entered as percentages and converted to decimals. The model treats their annual averages as constant and estimates useful thermal energy rather than electrical consumption.
What the result means
The result is the estimated amount of useful heating or cooling energy delivered over one year.
Compare it with annual building thermal demand using the same energy units and service type.
Given: Rated thermal capacity = 12 kW; operating hours = 2,400 hr/year; average load = 65%; seasonal adjustment = 92%.
Calculation: Base output = 12 × 2,400 × 0.65 = 18,720 kWh. Adjusted annual output = 18,720 × 0.92 = 17,222.4 kWh.
Result: Estimated useful thermal output is 17,222 kWh per year, equivalent to about 1,435 full-load hours.
Is thermal output the same as electricity use?
No. Thermal output is the heating or cooling delivered. Electrical use depends on efficiency, typically represented by COP, EER, or seasonal performance metrics.
How should I estimate operating hours?
Use controls data, utility analysis, or an hourly building model when available. For a rough estimate, count only periods when the compressor is expected to operate.
Can the seasonal adjustment exceed 100%?
It can be used above 100% only when the rated reference condition is conservative relative to expected average operation. Manufacturer performance data should support that assumption.
Why use both load factor and seasonal adjustment?
Load factor describes how much of rated capacity is delivered while running. Seasonal adjustment captures broader effects such as temperature variation, cycling, or distribution performance.
Can I use this for cooling output from a geothermal heat pump?
Yes, if all inputs and the capacity rating refer consistently to cooling. Do not combine heating capacity with cooling operating assumptions.