For Jason’s family, switching from a conventional 80-gallon electric water heater to a Cala system has delivered dramatic early results.

Water heating cost more than cooling

According to Jason’s Duke Energy Home Energy Report, water heating cost an estimated $708 from June 9, 2025, through June 8, 2026. It was his home’s largest energy-cost category for the year, even exceeding cooling.

The rate that makes timing matter

Jason’s power provider is Duke Energy Carolinas. Under his Time-of-Use plan, electricity costs $0.122 per kWh from 5:00 a.m. to 11:00 p.m. and drops to $0.061 per kWh from 11:00 p.m. to 5:00 a.m.

What changed after Cala

Since installing Cala in June, Jason says his household’s energy consumption has dropped so significantly that Duke Energy can no longer isolate the water heater’s usage. According to the Cala app, the system has used 119 kWh so far—an average of approximately 45 kWh per month.

At that rate, Jason projects that Cala will use approximately 540 kWh annually. At Duke Energy’s standard electricity rate, that would cost around $66 per year—and potentially even less with Time-of-Use optimization.

Jason expects his household’s hot-water consumption to decrease further now that his son has returned to college.

“To go from over $700 per year with our old 80-gallon standard electric water heater to these current projections is incredible.”
— Jason

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For Jason and his family, the early results show what’s possible with a more efficient and intelligent approach to water heating: substantially lower energy use and dramatically lower projected costs.

“Cala has saved our house power bill soooo much money. I love the system and they keep innovating by adding things like Home Assistant compatibility. Their customer service is the best. Every time I have called (only twice) they are super fast at responding. Get this for a great way to save on your bill.”

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This story reflects one household’s experience and projections. Duke Energy’s category estimate excludes taxes, riders, and service fees. Actual energy use and savings will vary.

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