Buy evidence, not labels
Before ordering anything, make sure you can answer the chiller flow, pump curve, plumbing and environmental-rating questions below.
1. Tub
- Actual fill volume.
- Dimensions or shape.
- Insulation construction.
- Cover plan.
- Bulkhead locations/wall thickness.
2. Chiller
- Published BTU/h.
- Rating/performance-test note if available.
- Min/max flow.
- Operating temperature range.
- Indoor/outdoor rating.
- Connections, watts/amps/voltage.
- Manual, warranty, parts/support.
3. Pump
- Head-flow curve, not only max GPH.
- Wattage.
- Connection size.
- Inline/submersible suitability.
4. Filter
- Housing size and connections.
- Rated flow.
- Cartridge/micron type.
- Pressure-drop data if available.
- Replacement media availability.
5. Plumbing
- Internal diameter.
- Total length.
- Elbows/valves/reducers.
- Bulkhead compatibility.
- Service unions/valves where useful.
6. Site/electrical
Verify voltage, circuit capacity, GFCI/RCD requirements, outdoor exposure, condensate management and condenser clearance. Use a qualified electrician where required.
7. Red flags
No BTU/h
Only HP and marketing adjectives.
No flow requirement
You cannot verify pump compatibility.
No pump curve
Max GPH is weak design data.
Huge “up to gallons” claim
Without ambient/target conditions it is incomplete.
Indoor unit shown outside
Photography is not an environmental rating.
No manual/support
Harder to install and troubleshoot responsibly.
Run your exact setup
Use your real tub, temperature, ambient, exposure, pump, filter and plumbing. ChillSizer checks thermal capacity and real operating flow together.
Open the System Designer