Calculator Inputs
Example Data Table
| Area | Cooling Factor | Heating Factor | Climate | Insulation | Occupancy | Recommended Tons | Loop Length |
|---|---|---|---|---|---|---|---|
| 2,500 sq ft | 22 BTU/hr/sq ft | 30 BTU/hr/sq ft | 1.10 | 0.95 | 5% | 7.00 tons | 1,197.00 ft |
This example matches the default inputs in the form.
Formula Used
Cooling Load = Area × Cooling Load Factor × Climate Factor × Insulation Factor × Occupancy Multiplier × Diversity Factor
Heating Load = Area × Heating Load Factor × Climate Factor × Insulation Factor × Occupancy Multiplier × Diversity Factor
Required Tons = Max(Adjusted Cooling Load, Adjusted Heating Load) ÷ 12,000
Recommended Tons = Rounded up to nearest 0.5 ton
Airflow = Recommended Tons × CFM per Ton
Loop Length = Recommended Tons × Bore Depth per Ton × Soil Factor
Electrical Demand kW = [(Recommended Tons × Compressor W/Ton) + (Recommended Tons × Pump W/Ton) + (Airflow × Blower W/CFM)] ÷ 1,000
These formulas support planning estimates. Final design should still use project-specific load calculations, local geology, and equipment data.
How to Use This Calculator
- Enter the conditioned floor area served by the geothermal system.
- Add your cooling and heating load factors from design assumptions.
- Adjust climate, insulation, occupancy, and diversity multipliers.
- Enter airflow, bore depth, soil factor, and electrical allowances.
- Click calculate to view tonnage, loop length, airflow, and demand.
FAQs
1) What does geothermal tonnage mean?
Geothermal tonnage describes the heating or cooling capacity needed from the ground-source system. One ton equals 12,000 BTU per hour of thermal capacity.
2) Why does the calculator compare heating and cooling loads?
A geothermal system should be sized for the larger demand. The calculator selects the controlling load, then converts it into required tons and a rounded recommendation.
3) Why is the result rounded up to the next 0.5 ton?
Half-ton steps are common during early sizing. Rounding upward adds a practical planning margin while keeping the recommendation easy to compare with available equipment sizes.
4) What is the bore depth per ton input?
This value estimates how much vertical drilling is needed for each ton of capacity. Local geology, grout, pipe layout, and ground conductivity strongly influence the final number.
5) How does soil factor affect loop length?
The soil factor adjusts loop length for thermal transfer quality. Better heat transfer usually reduces total drilling depth, while weaker ground conditions may increase it.
6) Why is airflow included in a geothermal calculator?
Airflow helps estimate indoor air-side delivery and fan power. It also gives a quick check that ductwork assumptions stay aligned with the selected system tonnage.
7) Is the electrical demand value the exact equipment consumption?
No. It is a planning estimate using compressor, pump, and blower assumptions. Actual demand changes with equipment ratings, entering water temperature, and operating conditions.
8) Can this replace a full professional geothermal design?
No. Use it for screening, budgeting, and concept comparison. Final sizing should use detailed load studies, manufacturer data, and site-specific ground loop design.