Impulse Cooktop 1-Year Product Reliability Update

We’ve been shipping the Impulse Cooktop for over a year now and wanted to share an update about where we are at in terms of hardware reliability with real customer units in the field.  The short answer: over our first few builds, we have iterated on our design and manufacturing process to the point where we now have best-in-class first-year reliability for induction cooktops. 

The Initial Numbers

In our very first production run, which included some Production Validation Test units, we saw a 6.71% service call rate. For context, the industry average for induction ranges is around 5%, and best-in-class brands like Bosch sit at 1.9%. These figures come from Yale Appliance, which services a wide range of the industry and has the data to back comparisons across brands.

So out of the gate, with zero fixes applied, we were in the ballpark of the industry average. It was higher than we would like, but better than some premium brands. And since then, we have dramatically improved reliability. The table below reproduces data from Yale Appliance and adds in the first Impulse Cooktop production run and subsequent runs for comparison.

Note: The 36” Impulse Cooktop has only been shipping for about six months, so while we expect the service rate to creep up a bit, it won’t move too much since the vast majority of issues show up in the first few weeks of ownership rather than later in life.

What Went Wrong, and How We Fixed It

Here are the three main categories of issues we've seen in the field and what we did about each.

1. The reset button (this one was kind of dumb). Our display sits on top of a board with a physical RESET button positioned close to the display cable. During transportation, vibrations can cause that cable to become lodged against the reset button, constantly pressing it and preventing the screen from turning on. This was an annoying error. Customers would open the box, see a black screen, and assume the unit was dead. Some customers were able to dislodge the cable by tapping the top of the cooktop, but for others we had to replace the unit. The good news is this was an extremely easy design fix: We removed the button entirely from subsequent builds. There's no longer a hidden reset button for a cable to press.

2. The "bad" pan. Some pans' magnetic properties shift with temperature and power. On most induction stoves, this doesn’t matter since the pan remains usable under standard induction power ranges (0-3.7 kW). But with the Impulse Cooktops' power, a small subset of pans became unstable and caused electrical issues in our power electronics at high power levels. Fortunately (or perhaps unfortunately) for us, the specific set of pans that caused this issue were widely distributed as promotional items to many appliance showrooms. After a few high-profile issues, we were able to identify the issue and update our firmware to fix it. Previously, we would only check for power spikes at the start of cooking. Now we continuously monitor for power spikes at the micro-second interval. This prevents hardware issues and makes this specific set of pans usable at normal induction power levels. And the good news is, we are able to deploy this fix across the entire fleet of Powered-by-Impulse cooktops. So whether you’re an Impulse customer or a Zephyr customer, this issue has been solved via software.

3. The temperature sensor. No one else does through-glass temperature sensing on an installed induction stove, and it's the one part of our design nobody asks about. We treated it like consumer electronics, not a traditional appliance part: building and stress testing over a thousand units before we shipped the first one. Nevertheless, we saw a small number of issues in the field and have subsequently updated on production line testing to catch and eliminate the issues we encountered during production.

More Reliable Due to OTA Updates

Here’s a table showing our first year service call rate if you back out the three big issues that we have addressed. All production runs get more reliable as we exclude failures such as “Bad Pan” that have been fixed. We’ve also worked hard on improving our testing and QA processes at the assembly line to improve reliability across the board. The Impulse team is made up of consumer electronics veterans, and we built the cooktop to very high standards that people expect for their phones and other devices.

The Bigger Picture

Most of what we've described are new-in-box issues, not failures that show up over a product's lifetime. The underlying reliability testing was conducted on several hundred units over nearly three years of development, long before these units reached customers' kitchens.

And the number we're proudest of: zero remorse returns on the Impulse Cooktop to date. Have questions about your Impulse Cooktop, or want to talk to our team? Contact us; we'd love to hear from you.