The Boldr Kelvin is an unusual space heater—a sleek, mirrored panel designed to hang on a wall. Marketed as a high-tech solution to cold rooms, the $400 device has garnered attention for its minimalist design and energy-saving claims. However, a closer look reveals that while the Kelvin offers a unique aesthetic, its performance and practicality don’t always live up to the hype.
The Promise of Smart Heat
Boldr positions the Kelvin as more than just a heater; it’s part of an energy management platform. The device connects to Wi-Fi and tracks usage via an app, integrating with smart thermostats for automated temperature control. The idea is to deliver heat efficiently while providing insights into energy consumption.
The Kelvin utilizes far-infrared heat, which proponents claim is more effective at warming people directly without heating entire rooms. Unlike traditional resistance heaters with fans, it’s silent. But the reality is that all non-heat-pump heaters are 100% efficient : all energy eventually turns into heat, so no heater is fundamentally “more efficient” than another. The Kelvin’s appeal lies in its direct heating approach, aiming to warm occupants rather than the air around them.
Performance and Practicality: A Mixed Bag
While the Kelvin delivers a gentle warmth, it takes significantly longer to heat up than conventional heaters. The glass panel radiates heat slowly, requiring up to an hour to reach full temperature. Radiant heat also warms surrounding objects, slowly raising room temperature over time—a process akin to how sunlight heats asphalt.
More concerning is that the device radiates heat backward, warming the wall it’s mounted on. Even the second-generation model can heat the wall to over 80 degrees Fahrenheit, potentially degrading paint or wallpaper over time. The metal mounting bars can reach 120 degrees, a temperature high enough to cause discomfort.
The Kelvin also requires a stable 2.4 GHz Wi-Fi connection and an app that collects usage data. While the app offers features like scheduling and energy tracking, it has been reported to be glitchy, with inaccurate cost estimates. Setting up the app can be more complex than with other smart-home devices.
The Verdict
The Boldr Kelvin is a visually striking heater that promises energy efficiency and smart features. However, its slow heating time, backward heat radiation, and app inconsistencies limit its practicality. The device is best suited for small spaces where direct radiant heat is desired. If you’re looking for a quick, reliable solution, other heaters may be more effective.
The Kelvin’s true value may lie in its potential as part of a broader energy management system. But for now, it remains an intriguing but imperfect product—a stylish addition to the market that doesn’t quite deliver on all its promises.
