Boldr Kelvin Review (2026): Heats Your Body, Heats the Wall

Company cofounder and CEO Madi Ablyazov told WIRED in a video interview last April that he views the heater as just one part of an energy management platform that would allow homeowners to track energy usage and costs across devices as diverse as heat pumps and solar panels. Boldr is, at heart, a tech startup that happens to have a space heater.

The Wi-Fi– and Bluetooth-connected Boldr app tracks energy usage over time, potentially on multiple devices and in multiple rooms. Temperature and humidity are measured by one of multiple external thermostats, including a Klima smart controller ($165) that could ideally sync with your home’s other heat pumps or AC units.

Boldr app via Matthew Korfhage

The app is still a work in progress, however, and has changed dramatically over the past year. As with most smart-home devices I’ve tested, there’s a bit of trial and error before Boldr’s devices decided to play nice with my router. This is a known difficulty with all 2.4-GHz smart-home devices, whether meat probes or security cameras. Still, the Boldr app required more work than some.

Some of Boldr’s tools are glitchy, including an AI-guided feature designed to track and estimate energy costs. Boldr’s app quoted a downright nostalgic 10 cents per kilowatt-hour for my Portland, Oregon, residence—a rate my city hasn’t seen since 2020. Adjusting Boldr’s app to the current rate was also not as easy as simply typing in the rate that appears on my energy bill. I had to jury-rig a solution that involved math instead. Booooooo, math.

Other tools work more felicitously. I can set Boldr’s thermostat to drop its temperature at local sunset each day and raise it at sunrise—or at specific times of my choosing. I can also set the Kelvin to turn on when the temperature in a given room drops below a specific temperature or when the humidity reaches a prescribed level. Alexa and Siri can likewise be integrated for those who prefer to chat with their devices.

If I want to give the device (and Boldr) access to my location, I can also set the desired temperature based on whether I’m home or not. I verified that this worked, then turned location tracking off. Trust what you trust, I guess.

I do expect Boldr’s energy management system to continue to evolve. And there’s reason for optimism: It’ll be a useful tool with other heating devices. But the caveats do add up. And I doubt I’ll be using it with the Kelvin.

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