Total Dynamic Head (TDH) Calculator
Calculate Total Dynamic Head to appropriately size a replacement pool pump so you avoid cavitation, excess energy bills, and plumbing blowouts.
Technical Comparison
| TDH Range | Plumbing Type | Recommended Pump Type |
|---|---|---|
| 20 - 40 ft | Simple, short 2" pipe runs, no heater | Medium Head / Variable Speed (Low RPM) |
| 40 - 65 ft | Average 1.5" to 2" plumbing, heater, standard filter | High Head / Standard Variable Speed |
| 65+ ft | Long runs, in-floor cleaners, solar heaters on roof | Ultra-High Head (3.0+ HP) |
Frequently Asked Questions
Why do I need to know TDH?
Every pump has a 'Flow Curve' chart. A 1.5 HP pump might move 100 GPM at 30 feet of head, but only 40 GPM at 60 feet of head. You cannot size a pump without knowing your plumbing resistance (TDH).
How do I measure vacuum suction?
You need a vacuum gauge installed on the pump drain plug. If you don't have one, assume roughly 10-15 inHg for standard 2-inch plumbing setups.
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