The formula is easy; runtime is the real variable. Insulation, cover, ambient and target temperature determine how often the compressor has to run.
1. Basic formula
2. Pump base load
A 58 W pump running continuously for a 30-day month uses about 41.8 kWh. Continuous operation may or may not be appropriate for your exact system; follow equipment/water-management requirements.
3. Compressor runtime
The chiller runs heavily during pull-down and then cycles to replace ongoing heat gain. A better-insulated tub spends less time running once cold.
4. Example
A 450 W chiller averaging five compressor-hours per day uses ~67.5 kWh/month. Add a 58 W continuous pump (~41.8 kWh) and the system is ~109 kWh/month before accessories. Multiply by your local tariff.
5. Reduce operating cost
- Insulate the tub and use a fitted cover.
- Shade outdoor systems.
- Keep condenser airflow clean.
- Keep filters from choking flow.
- Avoid unnecessary plumbing heat gain.
- Choose the target temperature you actually need rather than automatically using the lowest possible setting.
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