Today, we’re announcing Cala’s integration with Home Assistant, the leading open-source software for home automation.  Used by roughly 600,000 active households, it connects solar, batteries and other major home systems into a single, locally controlled platform.

As is typical with Home Assistant, the Cala integration will allow homeowners to view many of Cala’s key metrics — such as available hot water, energy usage, and water consumption — directly within Home Assistant. That data can then be used to create automations.

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What makes this integration fundamentally different is that it’s  bi-directional. Cala won’t just send data to Home Assistant. It will also receive information from it.

Through Home Assistant, Cala can take in real-time information about your home’s solar production, battery state, and other connected systems — and adjust its behavior automatically. If solar output drops due to cloud cover, Cala can delay reheating. If you want Cala to wait until your home battery reaches 60% before running the heat pump, it can do that too.

This communication happens locally over your home network, which means decisions are made instantly, even if your internet connection is down.

Cala can do this because it was designed from the start as a fully integrated system — hardware, sensors, predictive controls, and app — making it uniquely ready to integrate with external energy systems.

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Why This Matters

Heat pump water heaters like Cala already reduce water heating energy use dramatically – for example, by 60-70% versus electric resistance water heaters. The next opportunity isn’t just efficiency, it’s timing.

By combining Cala’s thermal storage with Home Assistant data, water heating becomes a flexible part of your home’s energy system—shifting energy use to cheaper, cleaner moments without requiring constant manual control.

The result is lower energy costs, ample hot water, and a system that responds to the state of your home, not just the temperature in the tank.

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Timeline

The Home assistant integration is currently in BETA, with early access available now and a production rollout scheduled for the spring. Interested in early access? Email us at beta@calasystems.com to join the beta. 

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What Comes Next

This integration is the first step in Cala’s broader integration strategy.

We chose to start with Home Assistant because it provides the fastest path to enabling Cala’s integration with solar, battery and other home systems for as many customers as possible. We also know Home Assistant isn’t used by everyone. From here, Cala will continue building additional integrations—including solar inverters, home batteries, other automation platforms, and demand response/VPP programs—as we continue our integration roadmap. The ultimate goal is for Cala to join a common standard and, by doing that, to help accelerate its widespread adoption.

The goal is simple: your home’s major energy systems should talk to each other and the world beyond your home, all to benefit you.

This integration is just the beginning.

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