A hot tub’s bill is mostly heat loss. The water is already hot; the heater replaces what the cover, the air, and jets steal. A good cover and a modest setpoint do more than almost any other habit. Jets and the circulation pump add motor watts on top when you actually soak.
An uncovered spa in wind is a heater working overtime. Dropping the setpoint a few degrees when you will not use it for days is a real cut. “Ready at 104 all winter” is the expensive setting, and it is honest — some people want that.
Fill water is a separate water card. This page is electricity to keep and stir the spa.
Set a typical average wattage if you know monthly kWh from a submeter, or heater watts × estimated hours of recovery plus pump hours.
If the heater averages 1,500 watts for 6 hours of recovery in cold weather, that is 9 kWh — about 1.69 that day at 18.8¢, plus jet time. Mild weather with a tight cover can be a fraction of that.
Cover
An uncovered spa in wind is a heater on overtime. Dropping the setpoint when you will not soak for days is the real cut, not a different jet button.
Related
Usage estimate only — not a utility bill, load calc, or advice.