Boldr Kelvin Review

About the Kelvin Smart Electric Infrared Wall Heater

• Weight: 20 lbs (29 lbs for large size)
• Heating area: 100 square feet (200 square feet for large size), depending on ceiling height and insulation
• Power input: 450W (700W for large size)
• Rated voltage: 220/110V (220-230V/110-120V for large size)
• Wall mount: Included
• Wireless sensor: Included
• Power cord length: 69.7 inches
• Certifications: UL, CE, FCC
• Dimensions: 37.80 inches x 19.69 inches x 0.47 inches (W x H x D)

The Kelvin Heater is available in two sizes: regular and large. It also has a variety of potential power outlet types, which are determined based on your delivery address. With a heater like this capable of drawing up to 700W for the large model (450W for the regular one), it is essential to ensure the power cable is safe and rated for your installation. Therefore, be sure to provide the correct information regarding the heater's installation location when ordering.

How we tested

To properly test the Kelvin’s ability to manage a small room, I used it in my ~250 square-foot basement office with the unit facing my desk. I have an existing 1500W convection wall heater that was already mounted, so I mounted the Kelvin directly next to it and compared the Kelvin’s performance to that of the unit, as well as a smaller, portable ceramic 1500W heater from Lasko.

Temperature performance was tracked using the Kelvin’s included smart thermostat, with power consumption tracked across all three units using a SwitchBot smart plug.

What we like

It gives off plenty of heat without fans and nearly no noise

Standalone convection and infrared wall heaters are not as common in the United States as they are in Europe, but they’re used in many places that lack full-home HVAC systems. Convection wall heaters work similarly to other heating sources in your home, utilizing heating elements that sit along the wall and warm up cold air as it passes. This naturally fills the space with warm air over time.

Infrared heaters, such as the Kelvin, are also wall-mounted, but their infrared heat is more directional. This allows it to heat an area—still warming the room up over time—but splitting the difference between convection heaters and forced hot air.

These units are ideal for rooms that are consistently colder than the rest of your home, particularly when you spend most of your time in one area, such as a couch, bed, or desk. Wall-mounting a heater can allow you to conveniently and regularly manage the temperature in those rooms without resorting to clunky (and often unsafe) oil or electric space heaters that take up floor space and can be a tripping hazard.

The Kelvin does take up space on your wall, but it’s fairly unobtrusive, and the natural infrared heat process means it doesn’t need any fans to direct air. That means it clicks on, heats up, and starts generating heat without you hearing more than a few clicks as it powers up. Both sizes can also be used with a standard 110-120V outlet in the U.S., meaning you don’t need to worry about hiring an electrician or wiring the heater directly into your panel—saving you both hassle and money.

The heat feels comfortable and fills the room quickly

During our testing, the temperature in my basement initially read 64 degrees. The room in question is finished with drop ceiling tiles and foam insulation under the drywall on all sides. It typically retains heat very well, with no drafts and minimal heat loss due to its windows.

My existing convection heater can produce 1500W of heat, but I found the Kelvin’s 700W more than adequate for the task. The use of infrared heat didn’t distribute the heat as quickly, but I felt the heat right away, whereas I often have to walk over and check that my convection heater is actually on and hasn’t shut off. When the Kelvin was on, I could feel it.

In terms of performance, the Kelvin was able to raise my basement temperature to 72 degrees and maintain it without issue, similar to the overall performance of my 1500W heaters. While the heat stayed more directional and didn’t spread as fast as the others, it worked just fine at less than half the energy cost. If you run each of these three hours a day for three months a year at an average cost of 16 cents per kWh, the Kelvin will cost you about $30/year to operate, compared to about $65 for a 1500W heater for similar performance.

The installation is a breeze

Hanging the Kelvin on my wall took all of 10 minutes. All I needed to do was use the included drywall anchors and paper template, drill a few holes in the wall, and hang it. You do want to be selective about where you place it—the heat is most directed right in front of the unit, and it shouldn’t face a window—but once you have that down, just hang it, plug it in, and you’re on your way.

The app setup was actually the most time-consuming part of the installation, as the app requires you to hold it near where the cord plugs in to connect to your Wi-Fi. Be sure to check on the back if you have a classic or Gen 2 Kelvin (there’s a sticker on the back, though the front would make more sense) before you start. Once it’s connected, you’re good to go.

The smart features and monitoring are excellent

While we tested all our heaters using a power line monitor, the Kelvin does come with its own smart monitoring built in. That helps you control when the heater turns on and off, what temperature it should heat to (using an included wireless smart sensor to ensure the right areas are warm enough), and how much energy you’re using. You can even input your energy cost and see how much your bill will be for operating it—a nice extra that helps you avoid being surprised.

In terms of efficiency, it’s no surprise the Kelvin used the least amount of power of the heaters we compared it to; its infrared heaters can only draw 450W or 700W at a time, compared to 1500W for both of the other heaters. Turning electricity into heat is mostly the same, no matter which tech you use; it’s more about the kind of heat and how much it spreads.

There’s a place for all three types of heaters, depending on your needs, but being able to keep track of the costs is a huge advantage.

What we don’t like

You can’t easily move it around like some space heaters

This isn’t an issue with this design so much as it is par for the course with convection heaters, but the Kelvin is not something you can simply pick up and move to different rooms like a small, portable heater. You have to wall-mount it, and it’s not the kind of thing you’ll be able to figure out by trial and error.

As someone who has used a convection heater on my office wall for 5 years now, I actually prefer this setup because I don’t have to think about it. I keep a smaller, portable Lasko unit nearby for when I need to quickly add some heat to a different room or area—given the energy savings you’ll get with the Kelvin over a bigger space heater, that will pay for itself in no time.

You may need more than one for a large room

The Kelvin is designed to provide direct heat to the area in front of it, and a large room will likely be too spacious for this to be effective. In my basement, it did enough to take the edge off—and provided excellent heat right in front of it—but it would struggle to handle a 400-square-foot room by itself.

It gets hot to the touch

This is a minor point, but worth noting for safety: like most space heaters, the front of the device gets quite hot. The model we tested also resembles a glass-front whiteboard, so be cautious when placing it around children who may mistake it for something they can interact with. Touching it for more than a few seconds will hurt.

Warranty

The Boldr Kelvin comes with a 2-year warranty that includes full replacement cost. You can purchase an additional 2-year warranty on Boldr’s website.

Should you buy the Boldr Kelvin wall heater?

Yes, but only if you can install it where it will do the most good

All electric heaters work on the same basic principle: electricity passes through resistance, heats up, and the heat goes into your room. Some of them blow that heat around with fans, some let cold air draw naturally through them, and some use infrared heaters to direct the heat towards a specific area. The Kelvin (available at Boldr) is the third kind, driving direct heat without a fan by radiating it—much like being in the sun on a warm day. Leave the area and you’ll get some heat, but it works best if it’s right next to you. That makes it ideal for use in an office, living room, or bedroom, where you can position it to point directly at the place where you spend the most time.

In our testing, the Kelvin got a bit hot to the touch, but it directed that heat nicely in an area about 10 feet right in front of it and 5-6 feet to either side. If you went to the far side or corner of a room, it was less effective. But if you’re installing this in an area where you know you want heat in one spot, it’s ideal. In those areas, it used less energy to keep an area just as toasty as either of the 1500W heaters we compared it to—meaning you get the same comfort for less money.

Design-wise, it’s a very nice wall heater that is less industrial-looking than the competition. It looks a bit like a minimalist statement piece. The app is also well-designed and easy to use, and the general operation was a breeze once you get through the somewhat clunky app-based installation process. I had it installed in 10 minutes and the room heated in less than half an hour. Overall, this is a great heater if you have a very specific area you want to install it in and heat directly, you like the design, and you don’t mind paying a bit extra upfront to get a heater that looks like it was designed this century.